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  1. #1
    Light freak
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    Pond Scum - Homebrew bike light instructions (not dial up friendly)

    Here are some quick instructions for DIY construction of a handlebar mounted bike light. Not a bunch of information on batteries, bulbs, bulb wattage and angle types as I figure there is already a whole bunch of information out there (search function).

























    Pond light $8.00
    Handlebar mount $10.00
    MR16 bulb $4.00
    14.4V Battery/Charger $70.00

    Total $92.00


    ****WARNING****
    Do not leave this light running unattended or for extended periods of time indoors. These MR16 bulbs overvolted to 14.4 volts produce a generous amount of heat and need some air flow to help pull the heat from the housing and bulb.
    Last edited by scar; 12-05-2006 at 05:56 AM. Reason: found out non-members can view pictures

  2. #2
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    For some reason, I'm not seeing the instructions... What format are they? I saw your idea in the other thread, and I'm planning on doing something similar. If you can't get the file to work, could you e-mail it to me? I'll PM you my e-mail...

    Maybe it was a work thing, cause I see them now at home.
    Last edited by dnlwthrn; 11-16-2006 at 08:07 PM.

  3. #3
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    Nice build I think I'll be stopping off at Harbor Freight on my way home from work.

  4. #4
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    Can you post a link to your bar mount? This is one of the slickest homebrews I've seen. good job!
    What, me hurry?

  5. #5
    Light freak
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    Miscellaneous parts

    Last edited by scar; 12-05-2006 at 06:02 AM.

  6. #6
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    clean, tasty little design...i'm gonna buy one fo those trick bar mounts.
    "He can make even a global summit meeting seem like a kegger." M. Dowd, NY Times, 19 July 2006

  7. #7
    Just Joshin' ya!
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    Scar,

    Were did you get your replacement battery? Would you recommend the 14.4 volt 5000 mah battery from battery space?
    Getting a dropper post is like getting a bidet. I didn't know I needed one until I get one and boy, does my ass thank me.

  8. #8
    Light freak
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    NMPhi767 - My original Jet battery pack was 13.2V. I went with the 14.4V 5ah C cell pack with charger from batterypace.com for brighter light output and longer run time at the price of bulb life. Build quality is great. I will be buying the 14.4V 5ah water bottle version to run the Pond Scum light. Be aware - these 14.4V 5ah batteries are not the lightest (12 C cells). I just consider them a training aid!

    The battery/charger combo came with the an extra male waterproof cable that matches up to the battery for splicing into your current set-up or if you are building one. I am sure the water bottle version is the same.

    All said for the entire light system - battery with charger, Pond Scum light head ~ $100


    14.4V battery pack and charger combo
    http://www.batteryspace.com/index.as...OD&ProdID=2302

    14.4V water bottle and charger combo
    http://www.batteryspace.com/index.as...OD&ProdID=2462

  9. #9
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    What kind of epoxy did you use?

  10. #10
    Light freak
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    kokothemonkey - I used JB Weld, but I am kind of disappointed with the result. The JB Weld did not attack the surface of the light fixture, but rather just hardened on the surface. I can already see it seperating from the fixture slightly. This weekend, I am going to chip off the JB Weld and try again with some Devcon Plastic Welder. Supposedly it has a solvent in it that helps it "melt" to the bond surface.

    It helps to keep a screw threaded in the nut during the epoxy stage to keep epoxy out of the threads. I just turned the screw by hand during the drying stage to insure that I wasn't gluing the screw to the nut.

    Final screw length is critical as well. If your screw length is too long, it will bottom out against the light fixture and "jack" the nut and epoxy away from the light fixture.

    I am also going to not only rely on the mechanical joint of the screw and nut, but I am also going to apply epoxy between the adapter and the light fixture and between the adapter and the bar mount. Should be rock solid. Just make sure you have everything fitting the way you want before epoxying everything together.

  11. #11
    Light freak
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    A couple of photos of light mounted....

    PHOTO #1




    PHOTO #2


  12. #12
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    Thanks for all that info Scar.... Have my parts on the way....

    BTW, for those of you who want a helmet mounted version, you can also get that mount on the batterspace.com website as well.

  13. #13
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    did you use the MR16/C 12V 35w or the MR16/C 12V 20W? and pics at night with the coverage of the light?

  14. #14
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    Don't see the switch.....bulb choice

    does the lite have a switch...
    do you plan on incoproartating one....
    is the lite dimmable...
    are the bulbs from batteryspace decent quality compared to the ones from JET

    newbie so all apologies if the above questions are ignorant

  15. #15
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    If you want a switch with dimming function, you'll need to get some sort of controller. You could build one yourself, or get something like the "Light Brain." http://www.trailheadlights.com

    I'm thinking of adding one of these to a 2 headlight setup similar to scar's. I'll probably fab a mount to hold both lights, using a spot bulb in one and a flood bulb in the other. Estimated total cost, not including the fabbed mount is $140 with battery... At the same time, I've been pondering switching to 6V bulbs so I can run a single light mounted to my helmet powered by RC car batteries (I have a pack or two at home that are in the 3000mAh range). So it may be an interesting project... But its definitely a score on the housing setup. Thanks scar!

  16. #16
    Light freak
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    ladracer –
    My next one will have the switch listed in the links above.
    Not dimmable – On or Off
    Don’t know about the quality of BatterySpace bulbs. Have a couple on order.


    Merkyworks –
    I am currently using a MR16/C 12V 20W (36 degree Flood). I went with 20W for light output, run time and temperature control. But I do have a MR16/C 12V 35w (12 degree spot) on order to play around with. Haven’t thought about or had time to do any nighttime “beam” shots. Maybe later.

  17. #17
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    Quote Originally Posted by dnlwthrn
    I've been pondering switching to 6V bulbs so I can run a single light mounted to my helmet powered by RC car batteries (I have a pack or two at home that are in the 3000mAh range). So it may be an interesting project... But its definitely a score on the housing setup. Thanks scar!
    I've got a bunch of these around, was trying to figure out how to use them in lights but they are the flat kind that match with contacts in the car. Baffled by how to make them work in the light without soldering wires to the battery -- this would make it impossible to recharge. Any ideas here or do you have different batteries?
    What, me hurry?

  18. #18
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    Go to your local hobby shop, you can pick up the mating connectors for cheap. Make up a loom to connect them to your lights: either use one pack for 6V system, or wire two in series for a 12V system (7.2V packs). You should be able to get a connector to plug into your light system (is the one available on batteryspace.com the same as some of the major light co's connectors?). Then you can swap out packs as they die... I was thinking real simple for a homebrew setup: single pack, 6V light, switch. Put pack in camelback, light on helmet, switch built into light housing.
    Make sense?

    Another option if you don't have a hobby shop nearby would be:
    Tower Hobbies

  19. #19
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    Please post some night photos that show this light in action. thanks
    2006 Specialized Hardrock Pro

  20. #20
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    Quote Originally Posted by scar
    NMPhi767 - My original Jet battery pack was 13.2V. I went with the 14.4V 5ah C cell pack with charger from batterypace.com for brighter light output and longer run time at the price of bulb life. Build quality is great. I will be buying the 14.4V 5ah water bottle version to run the Pond Scum light. Be aware - these 14.4V 5ah batteries are not the lightest (12 C cells). I just consider them a training aid!

    The battery/charger combo came with the an extra male waterproof cable that matches up to the battery for splicing into your current set-up or if you are building one. I am sure the water bottle version is the same.

    All said for the entire light system - battery with charger, Pond Scum light head ~ $100


    14.4V battery pack and charger combo
    http://www.batteryspace.com/index.as...OD&ProdID=2302

    14.4V water bottle and charger combo
    http://www.batteryspace.com/index.as...OD&ProdID=2462
    So if I got the water bottle/charger combo, that would take care of the electrical side of things aside from a switch?

    Also you might try a product called Gorilla Glue instead of epoxy, that stuff is really strong, I used it for attaching a bracket in my engine bay to run my amp wires from the battery, and other random tasks and it holding.

  21. #21
    Light freak
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    Yes the battery/charger combo is all you need except for the light head. The Devcon Plastic Welder seems to be working great.

  22. #22
    Light freak
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    Pond Scum - Double Strength

    I decided to make a "dual" set of Pond Scum lights with switches this weekend. Here are a couple of pictures that I snapped with the lights installed.

    Double Strength





    Wiring Diagram



    Pond light (2x) $8.00 $16.00
    Handlebar mount (2x) $10.00 $20.00
    Switch (2x) $4.00 $8.00
    MR16 bulb (2x) $4.00 $8.00
    14.4V Battery/Charger (1x) $70.00 $70.00

    Total $122.00
    Last edited by scar; 12-04-2006 at 05:11 AM.

  23. #23
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    whats the life of the battery with 2 lights now? this is still with the 14.4V 5ah battery right?

  24. #24
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    why the switches? I would have thought you just pull apart the cable to turn it off? Also, how bright are the pond lights? night pictures would be nice.
    Last edited by Jarl; 12-04-2006 at 01:53 PM.

  25. #25
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    Merkyworks - The battery life is an unknown at this point. Here is what I am thinking.....
    Overvolted 12V bulb to 14.4V using 5ah battery should result in 2.75 hour run time. I was planning on just using one light for the uphill climbs and then switching to "Double Strength" mode for the downhills. Don't really see the need, but why not for an extra $20?
    If I use the two 20W lights full time on a fresh battery, I am calculating a run time of just under 1.5 hours.


    Jarl - The switches were installed so that I can run only one light on the uphills and switch to "Double Strength" mode for the downhills.

    I am sorry, but I don't understand your question about pulling apart the cables going into the battery.

    How bright do you want them? A 12V battery is going to give you yellow lights. A 13.2V battery will give you brighter, whiter lights, a little less run time, and a little less bulb life. A 14.4 battery will give you even brighter, whiter lights yet, even less run time, and even less bulb life. You have to weigh all of these variables in deciding how you are planning to use the lights and how much you want to spend on batteries.

  26. #26
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    Well in your lighting diagram you have the "water bottle", a coil of wire leading to a plug, then another plug leading to the lights. Couldn't you detach these two plugs to turn it off? (as they are in the picture)

  27. #27
    Homer
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    Quote Originally Posted by Jarl
    Well in your lighting diagram you have the "water bottle", a coil of wire leading to a plug, then another plug leading to the lights. Couldn't you detach these two plugs to turn it off? (as they are in the picture)
    You could also cut them with some wire cutters, also carry a 12V soldering iron to solder the two ends together when you want them to light up again. Sure as hell improved my soldering skils! But on the other hand, a simple button/switch is pretty practical.

    @Scar: what chemistry battery are you using? Considering the price I'd say NiMH, but you never know...
    Nice looking light BTW! Always nice to see what people come op with and mod into bike lights. And with 2x20W (@14,4V thats 24W a piece!) you should have 'plenty' light!
    ps. Ever thought of upgrading your lights with a Lightbrain? Multiple levels for even longer runtimes and with a single controllerbutton it also cleans a the bit of the cablework out.
    Last edited by brum; 12-04-2006 at 04:52 PM.

  28. #28
    Light freak
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    Jarl - You are exactly right, you can make them without the switches and just plug/unplug them between at the cable end of the light and the cable end of the battery like I made the first one in the instructions above. I just wanted the ability to run one at a time on the climbs to conserve battery life, be able to switch them both on for the screamin' downhills, and the ability to switch them both off to enjoy the stars all with the just a push of a couple of switches!

    I agree, some "beam" shots at night would be nice. The only problem is that it has been extremely cold here since I have built these and I don't feel like venturing out just to take photos at night. Maybe once it warms up a little.

  29. #29
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    you could turn the lights out in the house/room and snap a shot

  30. #30
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    ****Warning****

    I added the following warning to the end of the instructions above.

    ****WARNING****
    Do not leave this light running unattended or for extended periods of time indoors. These MR16 bulbs overvolted to 14.4 volts produce a generous amount of heat and need some air flow to help pull the heat from the housing and bulb.

  31. #31
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    was this an after thought or did you turn them on and walk away and found out that they were on fire.

  32. #32
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    They suggest "cycling" your NiMH batteries by charging, discharging, charging, discharging for 3-5 cycles. I have been running my light in my cubicle to drain the battery and you can smell it when it starts getting hot. All it needs is a little air flowing around it to cool it down sufficiently. Even the housing on my Jet Phantom helmet light gets very hot when run indoors with no air moving around it.

    I built one for my friend at work who commutes everyday. The bike rack just happens to be outside of the window next to my cube. I was looking for him to pull up this morning. I ran out there to feel how hot his housing was getting on the commute. Not much heat at all. Just barely warm to the touch.

    Did you know that the majority of the MR16 halogen bulbs are designed so that most of the heat exits out the back of the bulb? Plug in a bulb outside of the housing and power it up and see how much light (heat) escapes from the back of the bulb. You will be amazed. This is because this type of bulb is used in retail and museums and they don't want the heat beating down on the customers or products.

    I played around a little bit with this issue this morning. I remember reading on candlepowerforums.com that some people were using aluminum tape to cover the backside of the bulb and stop the light (heat) from exiting the back. I did the same thing with one of my bulbs.


    This definitely stopped the heat from exiting the back of the bulb. I was able to leave the light plugged in much longer in my cube. Now, without any air flowing around the light, the o-ring starts to get hot.

    Like I said earlier, there is no issue with heat as long as there is some air flowing around the housing. This is no different than any overvolted halogen light that you can purchase from a manufacturer.

  33. #33
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    It does get really hot. I tested my pond light setup in office with a fan running and it still got super hot. For run time calculations, I ran mine with 12 AA powerizer batteries wired in series from batteryspace (2.5 aH) and only got an hour flat. I also cycled the batteries three times and still only got an hour. I am curious to see what the run times are with the pre-made battery.

  34. #34
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    i wonder if lithium-ion batteries would work better for longer life

  35. #35
    Light freak
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    kokothemonkey - I am not a "sparky" by any means but here are my questions.

    What kind of charger are you using for your battery pack? Are you sure you are getting a full charge? What is the voltage of the battery pack when you take it off of the charger?
    Last edited by scar; 12-06-2006 at 05:20 AM.

  36. #36
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    anyone see any problems with drilling holes into the back of the housing for hot air escape?

  37. #37
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    BassChop - I responded to your PM. Did you get it?

  38. #38
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    well if you drill holes then water/moistior could get in....thats all i could think of

  39. #39
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    Hey Scar, you have a PM.

  40. #40
    Light freak
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    rattpoison - I do not see another PM from you. I got your PM on Sunday and sent you a lengthy response Monday morning. Did you get my response? If you sent me another PM today, maybe I am just not seeing yet.

  41. #41
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    Quote Originally Posted by Merkyworks
    i wonder if lithium-ion batteries would work better for longer life
    Yes and no. Lithiums have an advantage because the same size li-ion battery as a Nimh or NiCd will have more voltage and/or more mah. So in that sense they would. However, if you get a li-ion battery that has the same voltage and mah as a nimh or nicd, it will give you the same run time. It will be smaller and lighter though. I really simplified that explanation so please forgive.

    What sucks about lithium and homebrews is that lithium becomes dangerous if you discharge too much energy from it and at best it will not recharge correctly either. Unless you put in a method of monitoring the current and turning off the light if the voltage dips to far into your homebrew, you could really mess up your battery.
    Getting a dropper post is like getting a bidet. I didn't know I needed one until I get one and boy, does my ass thank me.

  42. #42
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    Quote Originally Posted by BassChop
    Anyone see any problems with drilling holes into the back of the housing for hot air escape?
    I don’t see any issues in this case. I know of a manufacturer who does this. It looks to me like it’s pretty well made inside, with everything being covered by spaghetti insulation. I would just check to make sure things are nice and dry every now and then.


    Quote Originally Posted by NMPhi767
    What sucks about lithium and homebrews is that lithium becomes dangerous if you discharge too much energy from it and at best it will not recharge correctly either. Unless you put in a method of monitoring the current and turning off the light if the voltage dips too far into your homebrew, you could really mess up your battery.
    It sounds like you understand the issues, but I just thought I’d make things clear to everyone. To be honest I wouldn’t even bother building a home made Lithium pack unless you have read up and really know what you are doing. A quality battery protection circuit is absolutely critical with these cells. These devices protect the pack from over discharge, over charging, over current draw and usually have a thermal cut-out too.

    If Lithium packs aren’t protected with a device like this they can get into thermal runaway, which cannot be stopped. The result of thermal runaway is a very, very nasty fire. These fires often burn at extremely high temperatures, and could more then easily burn your house down. Not to mention the highly toxic fumes that result. I’m not exaggerating in the slightest.

    If you’re not confident, or don’t want to spend the time to build a Lithium pack properly, go and buy a complete pack / charger solution from a reputable manufacturer.

    Dave.

  43. #43
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    well i was thinking of using


    or

    one 14.8V 4A
    http://www.batteryspace.com/index.as...OD&ProdID=2486

    i think these have all the protection that is needed, right????

    the thing is that it says that it cant run higher than a 15W halogen buld but i want to run a 20W halo. why does this matter?
    Last edited by Merkyworks; 12-13-2006 at 10:56 PM.

  44. #44
    Spanish biker
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    You are a phenomenon!!!!!!!!!

    Greetings - Saludos
    Warning!!! my english is very very bad, sorry.

    Easy DIY led light1
    Easy DIY led light2

    The Beast!!!

  45. #45
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    Quote Originally Posted by Merkyworks
    the thing is that it says that it cant run higher than a 15W halogen buld but i want to run a 20W halo. why does this matter?
    Because you will draw more than the battery is designed for and, for safety reasons, the battery protection will trip out and not let you turn the light on.

    But I run a 12 volt 20 watt using a 14.8 volt li-ion battery (which therefore draws 30 watts) and am able to get it light by using what someone described as ghetto softstart: switching the light on and off quickly a few time times. It usually starts on the third try. But you are better off building a proper softstart setup. There are quite a few directions here.

    Wombat

  46. #46
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    Or buy a battery from another manufacturer that will meet the power draw requirements that you need. Most Lithium Ion cells can deliver a fair amount of current continuously; often you will see cheaper packs bundled with cheaper, lower quality (cruder) protection circuits, hence cheaper performance.

    A mate of mine runs a 35 watt halogen, overvolted with a quality 14.8 volt Lithium Ion pack no problems at all.

    As Wombat mentions, a “soft start” circuit will often be enough to smooth the initial current draw that happens when a halogen globe is first turned on.

    Yet another alternative is to flick the power switch a few times which may be enough to trick the protection circuitry. I wouldn’t really want to keep on doing that in the long term however.

    Dave.

  47. #47
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    Quote Originally Posted by scar
    kokothemonkey - I am not a "sparky" by any means but here are my questions.

    What kind of charger are you using for your battery pack? Are you sure you are getting a full charge? What is the voltage of the battery pack when you take it off of the charger?
    The batteries and charger are from batteryspace, and the batteries get fully charged. When measured with a voltmeter, they read 16.8 volts coming from the batteries (12 AA in series), so I think that is my problem with the low run time. Anyone know why 12 AA at 1.2 volts each in series would give so much power when they should only be giving 14.4 volts?

  48. #48
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    Freshly charged cells will always measure a little higher straight off the charger with no load. If you were to hook your light up and measure the voltage across the pack after a few minutes I’m sure you would find that the voltage had dropped and settled.

    Your run time with a 2.5Ah pack overvolting a 12 volt, 20 watt globe sounds about right, considering you are running AA cells.

    I don’t care what people think, in my opinion AA cells are not a good idea in high current draw applications like this. You are much better off building a proper pack with larger cells like 4/3A NiMh cells.

  49. #49
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    Basic question : How does overvolting affect burn time/safety or anything else?

    Scar, How close to the 3.6hours (calculated) of burn time with your system?

  50. #50
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    Overvolting reduces burn time. In my case I overvolted a 12 volt 20 watt bulb by using a 14.8 volt li-ion battery. Using this battery means that the bulb now draws 30 watts (50% more than before). Burn time is reduced by (I think) about 1/3. Bulb life is also dramatically reduced: in my cases I now get only 10% of the original bulb life, but as my previous bulb
    lasted 5 years I am happy with this.

    Over volting also means that you may exceed the discharge rate for your battery: this is true of mine and it won't start unless I flick it on and off a few times to override the battery protection feature.

    Wombat

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    Wombat...thanks for your answer here and in the other thread!

  52. #52
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    BassChop - I have been using the formula previously mentioned that has you multiply the voltage of the battery (14.4V for example) by the amp hours (5ah) then divide it by the wattage of bulb to get an estimate on run time. If you are running a 20-watt bulb and overvolting to 14.4V, the bulb is running more like 25 watts.
    14.4 * 5 = 72 72/25 = 2.88
    Remember this is an estimate presuming everything is optimal, batteries degrade over time, I would multiply that final number by 75% and use that for a realistic run time guesstimate.
    2.88 * .75 = 2.16

    Here is a run time test experience from last weekend. I had only cycled my battery approximately 3 times. Took my battery with a full charge (just over 17 volts) and ran a single light until it went dim. Got 2 hours and about 20 minutes of nice bright light until it started to get very dim and yellow. I hope this might improve a little after a couple more full cycles of the battery, I don't know. Now if I add in another light I might get an hour of run time, don’t know, I didn’t have time to try it.

    Here is what I would expect for a run time using a 35W bulb (43 watts at 14.4V).
    14.4 * 5 = 72 72 / 43 = 1.68 1.68 * .75 = 1.26 hours run time.

    Another thing that I think factors into the reduced run times is the increase in wattage by overvolting. A 35W bulb runs at 35 watts using 12 volts. That same bulb runs at 43 watts using 14.4 volts. My battery pack measures just over 17V when freshly charged. Now what wattage is that 35W bulb running at? I am sure it figures into the equation, I just don't know how, so I use the old "multiply by 75%" rule. Seems to work.

    I saw in your post in another thread you mentioned the housing heating up. I am not sure if you noticed my post above about using aluminum foil tape on the backside of the bulb? It really works!

    Solution for right now - Just use any aluminum foil tape you can find at the home repair store. The glue on this tape is definitely not made to withstand the temperatures the bulb puts off so it will smoke for a while but it will eventually stop. The foil tape still is very effective in reflecting the heat back out the front of the bulb.

    Better solution - Find a source for 3M 433L aluminum foil tape. It uses a silicone adhesive made to withstand 600 degrees.

    Another soultion - Here is something you may want to consider. I have been looking at the Sylvania Tru-Aim line and noticed something on their product spec sheet. All of the versions of the Tru-Aim listed that they were designed to transmit heat out the back of the bulb (except one). These bulbs are used mostly in retail and photography where they don't want the heat "beating" down on the customer, products or subjects. The Tru-Aim Brilliant line uses an aluminized reflector to redirect the heat out the front of the bulb. I think this is the type of bulb we want for these housings seeing as they are sealed up and nowhere for the heat to escape except thru the housing body.

    Sylvania spec sheet




    Here is a great link with a bunch of info on Mr16 bulbs
    http://www.lrc.rpi.edu/programs/nlpi...hatAreMR16.asp

    This page from the above link says it all
    http://www.lrc.rpi.edu/programs/nlpi...edToKnow03.asp


    I have a couple of the Tru-Aim Brilliant bulbs coming in tomorrow; I will let you know how they work. I am also looking at some "energy saving" models to try to increase run time. Sylvania has an "IR" version that they say redirects the heat to the element to save energy. I have a couple of these coming with my order as well.

    Got any pictures of your light? I would like to see what you came up with.

  53. #53
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    Get The Heat Out Of Here!

    I thought I would try to emphasize why the Pond Scum housing or any other homebrew bike light using a MR16 bulb gets hot and how to reduce it. Like I have said earlier, the majority of these bulbs are used in retail, art galleries (check out the link I posted above for everything you would ever want to know about MR16 bulbs. Keep hitting NEXT on the bottom of the page for a wealth of information). The bulbs are specifically designed to transfer the heat out the back of the bulb.

    Check out this picture I took of a generic GE 12V MR16 20W bulb with a dichroic reflector powered up. This is the type of reflector the majority of the MR16 bulbs use. The bulb is pulled away from the housing.

    GE 12V MR16 20W 38 degree spot


    There is so much light (heat) coming out the back of the bulb you can't even see the bulb in the picture! The easiest way to mitigate the heat problem is to use aluminum foil tape on the backside of the bulb to help reflect the heat back out the front side of the bulb. I just used some foil tape I had lying around. The adhesive burned (smoked) off initially, but the tape is still adhered to the bulb. You will be amazed at how much difference this mod to the bulb will make.

    I just got some bulbs in today that are specially designed to transfer the heat out the front of the bulb. They use an aluminized reflector in place of the standard reflector. The difference is like night and day. Take a look at this photo; all of the light (heat) is coming out the front side of the bulb. You can even see the bulb in the picture.

    Sylvania Tru-Aim Brilliant 12V 20W MR16 8degree spot


    You can actually touch the backside of this bulb after it has been running for a couple of minutes. DO NOT TRY THIS WITH ANY OTHER BULB!!! I think I will probably use a little bit of the aluminum foil tape on this bulb around the base/socket area as there is a little bit of light (heat) leakage in this area. There is so much light (heat) coming out the frontside of this bulb, it is hard to hold your hand in front of it for any length of time without it feeling like it is going to burn a hole right thru it!

    Here is a link to where I found the bulbs. A little pricey compared to BatterySpace bulbs but I am hoping the light output is also greater on these bulbs. These are only these two options at 20 watts.

    Sylvania Tru-Aim Brilliant (#58569) 12V MR16 20W 8 degree spot
    https://www.lightbulbemporium.com/pr...asp?prod=58569

    Sylvania Tru-Aim Brilliant (#58570) 12V MR16 20W 36 degree flood
    https://www.lightbulbemporium.com/pr...asp?prod=58570

  54. #54
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    scar...thanks for all that info on the bulbs. I will get some pics up of my helmet mounted version shortly...Just need to make some final tweaks. I have done a couple rides with it, and have been very happy with the output of the light. It is very bright (using a 12v 20 watt, 38 degree flood light with the 14.4V/5000maH battery pack). Riding tight singletrack even down some steeps last night was no problem...have a mount for the handlebars, but not sure if I will bother to use two lights, doesn't seem necessary.

    Couple questions for you. I understand the calculations that everyone is using, except for one. How are you calculating the wattage when overvolting? Is this just a guess? It isn't critical, just curious.

    Reflecting the heat out the front of the unit seems to be a good thing, if that isn't going to melt the rubber gasket o-ring on the housing right behind the bulb or the housing in front of the light itself.

    Have you cycled through with the new bulb mounted in the housing? What were the results.

  55. #55
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    BassChop - I don't know where exactly I found this document but I happened to print it out. Lots of good information. Take notice how much the lumens go up in proportion to the voltage going up. I have been using these numbers for wattage of an over-volted bulb. I am sure someone will chime in with the formula for figuring this measurement out. Look forward to seeing your light design. I will be doing some run time test this weekend with a couple of different bulbs. I will let you know how it goes.


  56. #56
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    Quote Originally Posted by BassChop
    How are you calculating the wattage when overvolting? Is this just a guess? It isn't critical, just curious.
    Basschop

    You can use this site: http://www.angelfire.com/pa/baconbacon/page2.html

    Enter the original volts and watts (12v & 20 watts) and it calculates the amps and the ohms: 1.6 and 7.2. Then delete everything but the ohms (as these remain constant and enter in your new voltage (such as 14.8) and recalculate. Using 14.8 volts and 7.2 ohms you get 2.0 amps and 30.4 watts.

    Wombat

  57. #57
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    WOW!!!! Damn, I might actually have to try something like this. You make it look sooooo easy, scar.

    I was wondering about some cooling holes in that, too. I see that you have tape (reflective, i'm sure?) on the back of the bulb. Wouldn't removing that help the cooling side of the equation a little more than the extra light output? The heat could at least get "into" (absorbed by) the plastic easier and aid in cooling.

    Just a thought.
    I ..... need ..... DIRT!!!!!

    ... and cookies.

  58. #58
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    yeah...scar did make it look easy....and it was.

    Below are my pics of a helmet mounted version. I used the same Harbor Freight Housing, bulbs, wires, battery and charger (14.4Volt - 5000maH) and switch that scar mentioned above. My assembly is crude on this iteration. Wanted to make sure I was happy with result and get out on several rides with this before I went too nuts with the design.

    I ground off the bottom of the housing and epoxied it to a piece of hard wood (ebony in this case). Before adhering, I drilled a hole through to be able to use the thumbscrew through the helmet mount bracket. My thought with this was to determine what angle I would want in the light's final design, and have that adjustability as I tested. It doesn't need any as the angle is fine coming right off the helmet is right on, and for now I have just cranked down on the thumbscrew to hold it tight and flat. Most likely, I will cut off the little plastic screw ears from the helmet mount and epoxy the housing right onto that removeable helmet mount.

    I have taken this sytem out on 4 night rides this past week using a 20 Watt bulb (38 deg flood). Been very happy with the results. I find the light to be significantly more useful than an off the shelf unit I had purchased earlier this year for around $165.. I am riding tech single track in the thick woods, with plenty of up and down...but havn't rode in a situation where I am exceding 20mph down hill.


    I have been getting well over 2 hours burn time with the unit. I do run the battery way down even if it means turning it on and running it in the house till it is dead.

    Cooling...scar was right about the air flow when riding. It is adequate when riding....at least at this time of the year in New England. Most of my rides have been when temps are in the 20s - 30s. When I am buring the battery down in the house, I take the light out of the housing and let it dangle to keep the housing from melting

    Next stage is to figure out a headlamp style to use for cross country skiing...if we ever get snow in new england this year. I will most likely go for a bit less output or burn time and lighter batteries for that...
    Attached Images Attached Images

  59. #59
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    i just back from lowes and got a 20w 12v mr-16 bulb (flood) that is made by GE and it already has the back covering on it. I just tested it as well and it holds more light in than the Sylvania Tru-Aim Brilliant 12V 20W MR16 8degree spot.

  60. #60
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    BassChop - Great job on the helmet mounted version!! I am definitely going to order a helmet mount and copy how you mounted the switch, I like it. Have you tried running the foil tape on the back of the bulb?

  61. #61
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    Havn't done the foil...I am planning to get a bulb that has the reflector coating already on it. ...probably get the GE flood that Merkyworks got at HD.

    Merky and Scar ::: How has the rubber gasket held up with heat emitted through the front?

  62. #62
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    Quote Originally Posted by Wombat
    Because you will draw more than the battery is designed for and, for safety reasons, the battery protection will trip out and not let you turn the light on.

    But I run a 12 volt 20 watt using a 14.8 volt li-ion battery (which therefore draws 30 watts) and am able to get it light by using what someone described as ghetto softstart: switching the light on and off quickly a few time times. It usually starts on the third try. But you are better off building a proper softstart setup. There are quite a few directions here.

    Wombat
    I hope that you have some new and safe lithium ion cells. New ones can't explode because they turn off before they explode, but the olders just explode. One cell gives already a nice hot fire/explosion, I guess you have 12 cells...


    Would be a pity for your bike (and legs)

  63. #63
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    I've been bumming about the last month or so because its been getting dark right when I get home from work. I'm thinking of trying this out. I know how to solder and make battery packs from my R/C car days, so thats not a problem. I just have a few bike night noob questions. How long do these bulbs last when they are overvolted like this? Would one of these with a 20 watt bulb be good for light trail riding on trails I know, just to get some dirt miles down and stay sane? I don't expect to ride for more than an hour or slightly over an hour at a time, would a AA pack be okay? I don't know how many amps they are safe for, all my experience is with sub-c.

    Thanks

  64. #64
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    Quote Originally Posted by Stregone
    How long do these bulbs last when they are overvolted like this? Would one of these with a 20 watt bulb be good for light trail riding on trails I know, just to get some dirt miles down and stay sane? I don't expect to ride for more than an hour or slightly over an hour at a time, would a AA pack be okay? I don't know how many amps they are safe for, all my experience is with sub-c.

    Thanks
    stregone,
    double AA's would work. I've strung together the battery holders from radio shack to hold 12 rechargables (1.2a x 12 = 14.4) and run 12 volt 20w or 10w bulbs. Overvolt the 12 volts (to 14.4) and it'll run brighter and the life won't decrease that substantially. even so, a bulb costs less than 8 bucks normally so no big deal there. run time, you'll be fine, and you could even set up a 10w and a 20w and have over an hour of use (depending upon the ouptut of the batteries). if you decide to set up two lights, provide a switch on one or both and you can decide how much light you need based upon the conditions.

    coming from an rc background, you can pick up premade 7.2v rc packs at radio shack and use rc connectors in the wiring to make a 14.4 volt battery if you don't want to use AA's.

    have fun. post up when you've built your kit

  65. #65
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    BassChop - I have not had any problems with the o-ring heating up. I have just been leaving it running out in the garage while I am tinkering with some other things. Absolutely no air flow.

    Stregone - I am going to have to stay out of the battery debate as I am not experienced in this arena.

    Earlier in the thread kokothemonkey posted that he was using 12 AA's and getting a run time of 1 hour. I don't know if this has improved for him or not.

    Low-Rider expressed some concern about this
    AA cells are not a good idea in high current draw applications like this
    Moving on to bulb life, here is a link to a graph that tries to show the effects of overvolting these bulbs.
    http://www.myra-simon.com/bike/lights.html#overvolting

    Where all of the lines intersect at the center of the graph is 12 volts. When overvolted by 120% to 14.4V (Blue line) the light ouput (Green line) goes up by over 80% but the bulb life (Red line) is reduced by 90%. Sounds pretty bad, but these bulbs have a life of 3000-4000 hours. Reducing the life by 90% means a new estimated life of 300-400 hours. That comes out to equally about one hundred 3 hour night rides. Good enough for me! Just make it a habit to replace the bulb every season and you should have no problems.

  66. #66
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    I haven't posted any progress yet, as I haven't done anything with my lights yet... I got a pair of the harbor freight lights, and just yesterday ordered a battery pack (5aH from Batteryspace) and controller (Light Brain). I'm going to make a dual beam setup for bar mounting. I've got it almost all figured out, I just need to fab the bracket now. I'm hoping to get this done in the next two weeks or so (before classes start again).

    I'm liking the way this thread has developed! Anyone else have a version that they've come up with using these lights?

    One other question I have deals with the ring that clamps the bulb in place. Doesn't it cut down on the beam? It seems that with the MR16 bulb, the black ring would cut down on the width (diameter?) of the light beam, reducing any bulb to effectively a spot bulb. Am I correct in this? I don't have any bulbs to try yet, as I haven't picked them up either...

    Dan

  67. #67
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    Quote Originally Posted by Stregone
    How long do these bulbs last when they are overvolted like this? Would one of these with a 20 watt bulb be good for light trail riding on trails I know, just to get some dirt miles down and stay sane?
    When I first ran the 14.8 volt battery the bulb blew after about the second start. But it was 5 years old. The figures indicated that at this voltage the bulb should last for about 10% (a 90% reduction) of its life at 12 volts.

    The one bulb lasted through the winter just past, probably around a total of 100 hours, and I am still using it for an occassional night ride with my daughter now that it is summer.

    Wombat

  68. #68
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    This site mentioned here says that a 14.4v 20 watt bulb pulls 1.7amps, which is less than 1C for a 2500mah AA cell.

    According to this over at candlepowerforums AA can handle it.

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    I use a 38 deg flood with the HF housing...its still a flood...no complaints.

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    Scar ... thanks for the build info! Under $100 for a dual 20 watt light setup (including battery and charger)! You saved my marriage!!!

    BassChop ... I like the way you mounted the switch to the back of the light. How'd you attach it? Some type of epoxy or PVC cement?

  71. #71
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    dezmo...I used CA (cyanoacrylite) glue (aka superglue) and accelerator since I had it handy...Epoxy would work just fine.

  72. #72
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    Quote Originally Posted by Merkyworks
    i just back from lowes and got a 20w 12v mr-16 bulb (flood) that is made by GE and it already has the back covering on it. I just tested it as well and it holds more light in than the Sylvania Tru-Aim Brilliant 12V 20W MR16 8degree spot.

    Do you have a model number for this? I went to Lowes as well as HD and couldn't find one that had the back covering.

  73. #73
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    Variation to avoid the need for an adaptor

    Guys love this thread.

    was following the driections of scar and buiding the light with the button on the back like basschop when i broke the outside nutholder on the light assembly.

    necessity the mother of invention....i came up with this...





    no need for an adaptor

    simply grind off the nutholder thingy on the light drill hole for the bolt in the same area.

    grind off the quick release mount like the picture shows and then put bolt, flat washer on outside off lamp and lock washer and nut inside light housing.

    i also took the switch down a bit, no need for the button holders.

    hope you like it.

    many thanks to scar and basschop for thier ideas and hard work

  74. #74
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    what bulbs are you guys using, I have been looking for a spot beam, and its not easy. Are you using flood beams? and are they working ok for you. I hooked one up with the flood beam to my car battery and the visibility sucked.

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    20 Watt, 12Volt, 38deg Flood - MR16. I have both Flood and spot here, but prefer the flood. Visibility is great. You can get these at HD and Lowes.

  76. #76
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    Some real good stuff going on here! I have been off work shoveling snow and sledding with the kids for what seems like a month. I have been checking the thread, just haven't had time to respond so here it goes.

    dnlwthrn - The outer ring that retains the bulb does not seem to restrict the light in any way, if so, it is undetectable. Nothing to worry about here. Please post some photos of your light when you are done (even during the build would be cool).

    dezmo - I am glad that you appreciated the info. Please post some pics of your light when you have completed it.

    ladracer - Looks great! I knew when I posted this it would get the creative juices out there flowing. I like the way you expanded on BassChops' switch mounting scheme and ground off the tabs for the straps. I think I could get the switch and a cable holder squeezed together on the backside. Definitely going to give it a try on my next one.

    wake_100 - I have to confess that I have not even rode with this light on my bike yet except for a quick sprint around the neighborhood one evening about a month ago. I do have a product tester (a friend at work that I built one for who commutes year round) that has tested a couple of different bulb types, here is what he has said. The first bulb I gave him was a GE 20W 38 degree flood that I got at the grocery store. The first day he commuted with his light system, his comment was "that is one bright light". I then got in an order from BatterySpace and gave him a 20W 12 degree spot from BatterySpace. His comment was that this was the "mother" of all lights. Unfortunately he dropped his light onto the concrete one cold morning and killed the bulb. I then gave him a 20W 38 degree flood from BatterySpace. He really did not like the flood as he wanted the "beam" that the spot provided. I think the "spot" bulb really pierces the ambient light while the "flood" just appears to amplify the ambient light seen in front of him. I then gave him a Sylvania Tru-Aim Brilliant 20W 8 degree spot. He commented that he really likes the spot over the flood for commuting. He also commented that he thought the BatterySpace bulb was a brighter bulb and did not see any extra value to the Sylvania bulb. Remember this "testing" is being performed by a commuter that has some ambient light from streetlights at times and really isn't concerned about many obstacles. He wants to see what is coming up in front of him and wants to be seen. On the trail, my preference is a "spot" on the helmet and a "flood" on the bars. Also, remember your car battery is only 12 volts. Much of this thread has been directed at overvolting these bulbs to 14.4 volts. Overvolting these bulbs greatly increases their light output.

  77. #77
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    Scar,
    I'll post pictures as soon as I have something to photo... I'm working with a co-worker and the CNC right now to make bar clamps (I don't exactly like the style of the Batteryspace ones) and trying to figure out where/how to install/seal the controller. I'll try to post some in-process photos as soon as the chips start flying.

    To be more exact as to what I'm doing:
    2 Harbor freight light housings
    MR-16 bulbs (right now 1 spot, 1 flood)
    Light Brain Twin Plus regulated controller (http://www.trailheadlights.com/)
    Batteryspace 14.4V 5aH waterbottle batterypack and fast charger
    Custom clamp mout for the bars, allowing individual adjustment of the two beams.

    Should be interesting... Thanks for the idea, and thanks to everyone else for their versions of this homebrew!

  78. #78
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    scar I have noticed, I have 2 battery packs that are for a RC car that I played with and wired them differently to get double power or double voltage. I was using just the MR11 20W spot and I was amazed on the difference between 7.2V and 14.4V It lit up atleast 100ft when at 14.4V. I went for a test ride in the woods at 7.2V and worked rather well. Really yellow, no I'm working on the new battery pack. Its still in the imporovement stages.

  79. #79
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    Yay! The last part I needed (Light Brain) arrived today! Now its time to start wiring! I still have to figure out what I'm going to do for the switch, but that's just a Radio Shack away. Still working on the design for the bracket, so that may take a while...
    When I get things wired, I'll try to get some light output photos up (MR-11 v. MR-16 flood v. MR-16 spot).

  80. #80
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    Can someone get me the dimensions on the batteryspace mounting bracket? I need to know the distance between the ears...

    I've been working with a coworker on mounts, and we decided that it would be cooler to machine a complete housing. Hoping to do the CNC file today or tomorrow, then its just a matter of getting it cut out. I'm going to use the Battery space mount (like the QR capability), and ordered both the helmet mount and the bar mount. We'll see what happens. Its kind of frustrating sitting here at my desk with the battery, lights, lightbrain, etc. all staring at me waiting to be used, just for lack of a drawing...

    Oh well.

  81. #81
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    The distance is 3/4 inch for barmount 002. I had the same question 3 weeks ago and I sent them a mail and this was the answer.

    Mark

  82. #82
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    thanks... I sent them an e-mail as well, but I figured someone here would be quick to answer.

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    Scar ... thanks again for the build. Sorry that I have been a slackard. Anyway I got my system completed last week and took it out for a test with a buddy. He said to post that this system BLEW AWAY his 6v Marwi light (2 bulbs, 15w & 20w MR11). He ended up making me ride about 50 yards back since I was washing his light out so bad. Since he is good and I stink this was not hard.

    I ended up putting together a 2 light helmet mount system. I used a 20w flood and a 20w spot. My intention was to use the spot for the faster sections and turn it off when possible to preserve battery. I got (12) 5000 mAh 'C' cell solder tab batteries from Battery Space. Switches, connectors, and the cheapest charger I could find also came from Battery Space. I rigged up the brackets from stuff I had laying around. Total cost was $96.03 including tax and shipping. That's right ... less than $100 for an awesome dual light set up.
    Light Side.jpg

    Light Bracket.jpg

    How does it work? We weren't riding anything too tough but the light was great. I hit over 25 mph a couple of times and never worried about overrunning the light. Battery life? We rode 55 minutes and my friend's light was dying. I took mine home and burned it another 50 min! I'd guess that I had the spot on for about half the time. I'll probably try out a 10w spot because I don't need the challenge of reaching up to my helmet as I start a fast downhill.

    The light kit modified for the MR16 is great. The waterproof switches are nice and the 14.4 volt battery setup is good. My biggest issue has been the mounting. For the current set up I actually routed a slot in the tab of the light. I glued in a piece of plastic with a hole drilled. We'll see if this is sturdy enough (if not then I will drill a hole in the light and use an eye bolt). The bracket is made from some '69 Camaro sheet metal (don't ask) with a 1/4" bolt welded on each end.

    My biggest issue was the battery pack. If I was doing this again I would seriously consider a pre manufactured set up from Battery Space. I did not realize how thin the casing is and I shorted one of the batteries on assembly. I caught it pretty quickly and fixed the problem (sharp edge) with the Dremel. I'm just not sure it's worth saving $15 to sacrifice peace of mind. I used some heat shrink plastic sheeting to encase the battery. If everything keeps on working then I'll go ahead and plasti dip it. Oh yeah, I went cheap on the connectors. If I was doing it over I'd go with the nicer ones ... again $4 saved probably isn't worth the worry.

    One last thing before I end my rambling. Battery life and light power. Some of you guys are making this too hard. You need two equations to figure THEORETICAL life. You can then apply the safety factors you want.
    V (volts) = I (amps) * R (resistance in ohms)
    W (power in watts) = V (volts) * I (amps)

    For all practical purposes a light is a resistor so the first thing to do is calculate the resistance of your bulb. If you have a 20 watt, 12 volt bulb then:
    I = 20 watts / 12 volts = 1.67 amps
    R = 12 volts / 1.67 amps = 7.2 ohms

    So with a 5000 mAh battery you should get about 3 hrs burn time. Stay with me. Now lets say you are going to run this at 14.4 volts.
    I = 14.4 volts / 7.2 ohms = 2.0 amps
    W = 14.4 volts * 2.0 amps = 28.8 watts

    However you have cut your burn time to 2.5 hrs with the same battery. There are a lot of things that affect battery life like "how hard" you pull it down, more amp draw drains a battery faster. Also the voltage on a battery dc system is constantly decreasing which also effects light output and battery life. I don't mean for this to be the end of battery life and light discussion, I just wanted to put the science of it on the table.

    THANKS AGAIN TO SCAR, BASSCHOP, AND EVERYONE THAT HAS POSTED ON THIS THREAD!!!

  84. #84
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    Dezmo....

    1994 called. They want their helmet back! Vintage Specialized Sub 7 helmet. Where did you find one of those? I knew a guy who had two of them.... I need to see if he's willing to part with one.

    Seriously... nice light! I'm close to taking the homebrew plunge myself.

  85. #85
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    Dezmo...that looks good! Both of us have some old helmets...mine is from '97....

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    Basschop ... thanks, it works great!

    I seem to recall getting helmet from some pudgy kid trying to take his criterium success west in the early '90's. He had an old Astro cargo van full of these and rode an Eddy Merckx. Wonder whatever happened to him ....

  87. #87
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    dezmo - Great job! Gotta love the price too! Did you get your bulbs from BatterySpace? If not, what are running?

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    Yes, I got the bulbs from BatterySpace. I have to say that they were an excellent supplier. It took a week for the shipment to get to me but that is not their fault ... blame UPS. The 38 deg flood seemed to have a slight halo effect so I got a name brand bulb from Home Depot. It was a waste of money ... the generic BatterySpace bulb is every bit as good.

    Oh yeah, to anyone ordering from BatterySpace ... google BatterySpace and coupon. You'll find they generally have a 5% off discount code which helps offset the shipping cost.

  89. #89
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    Sounds like a good idea to use the Light Brain, although it's not obvious how to mount it. I am looking at 2 MR-16 20W spot bulbs with the controller. The cabling might be cleaner if the controller is located near the lights on the bars or stem, vs. near the battery in the water bottle cage. I'll be intersted to see what you come up with.

  90. #90
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    Just noticed...

    that Harbor Freight has the pond light on sale this weekend for $6.99. Can't help but get a spare to have on hand at that price. It is listed on page 2 in their "Parking Lot Sale" ad for March 2, 3, and 4th. Couldn't find it on their website to link??

    Also noticed that BatterySpace has new style of waterproof switch listed that I hadn't seen before (might not be so new).

    Waterproof Switch
    http://www.batteryspace.com/index.as...OD&ProdID=3213

    I know there has had to been a couple of more people building up lights this winter, come on, show us what you got!

  91. #91
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    dgwright,
    Yes, the Light Brain is best if its close to the bulbs (manual says 12" or less from controller to bulbs). If you're running a setup similar to scar's with two of the pond lights on the handlebars, you could pick up a cheap plastic "box" from radioshack to mount the Light Brain in. Mount the switch to it, run the wires through it, and you should be fine (if you're worried about water penetration, seal the wire holes with silicone caulk).

    I'm still sitting on my stuff. I've got everything I need, I just got picky about the setup. We've got a housing designed in AutoCAD, now I need to sit down with the machinist and get tool paths run. Once we get that, chips will fly! I'll try to get pictures of the process. The plan right now is to make it out of aluminum (we have a "scrap" block that's just about the right size). Once I decide whether or not I like the idea, I may remake it out of ABS, depending on cost.

  92. #92
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    scar wrote: "I know there has had to been a couple of more people building up lights this winter, come on, show us what you got!"

    I'm new here, I'm overwhelmed by the vastness of this forum. Admitedly I probably posted in the wrong threads, at least my DIY light anyway. The reality of "a kid in a candy store" is, he can't eat it all. Though I try, I can't read it all. Instead of adding duplicate content to the forum here is a couple of links to them.

    scar - Your homebrew pond scum light is brilliant. Great name too. I sort of did the same thing using the head and end cap of a D cell maglight w/MR16. It was bulletproof. Something bugged me about it though. It was too bulletproof. Probaly survive a iraqy IED.

    You know when your finished when your done tinkering and I had to do some more. I ran a dual light setup too, until I made my current DIY light. This light kicks over them all. In fact its too bright for the streets with traffic. I finally stood about 100 feet in front of it tried looking at it. and ya its damn bright, even at a 45 deg. angle from the beam. This is what I run now. 12v 20w MR16 8deg. beam, 5000hr avg life over volted to 16.5 volts (12 AA's in series X 2 or 3 parallel, ie., 24 or 36 AA's total) These AA's are the 2500mah NiMh kind, and can be used in a 15 minute charger. I think these AA's are so good at holding lots of power and releasing lots of power I went heavy into the 15 minute chargers. With 5 (4) bay chargers one can go from no power to out the door with full power in 45 minutes. Thats 52 AA's (36 for the halogen 3+hrs runtime and 16 for my helmet light 4+hrs runtime) which is my setup for a night epic.

    Honestly I've tried to stay out long enough to run out of power a few times and thats why the plus signs in the runtime numbers. I really don't know much past the hours givin. I do know that when I use it as needed (intermittently) it will last all night.

    So overvolting that high may give me 2000 hours from it. 10x longer than some of those tweaky expensive bulbs. Been running it for almost two years. Forget about any MR16 over 13deg beam spread, Trust me, the tighter beams reach farther and still spill enough area light. On the streets I have a 6v high pressure xeon $20 flashlight head mounted with 1/16"dia. shock cord and a 5.2v battery pack to run it. And of course, cateye LED blinkers front and rear.

    I need to learn not to be so long winded. Really I'm just trying to share my experience with DIY'ers. I enjoyed your posts and hope you can get something from my posts.

    Light setup:
    HID DIY, working proto + Pics

    Battery:
    DIY Lights: How to build your own battery...

  93. #93
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    UrbanPounder - Great looking light, very clean. That battery is intense, very clever use of PVC. A total of 52 AA's (helmet and bar light)-that is incredible. The PVC battery holder looks very large in the picture by itself, but I am sure it is not that big. Does the 36 battery module fit right in your Camelbak or mount on your bike? Just curious. Once again, great job on the light and batteries. Bring on the night time!

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    Thank You Scar and everyone else who has posted in here, lots of great ideas.

    My parents picked up a couple pond lights for me last weekend, and it will be a couple weeks before they return from Florida. So I have a question that would be easily answered if I had the light in front of me.

    Why use MR16 bulbs? I have a bunch of MR-11's from other projects, and was hoping to keep using them. Also, all my batteries are 7.2v, so it would be nice to stay with 6v bulbs. Will a MR-11 with glass cover not fit in the light without modification?

    Thanks

  95. #95
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    [QUOTE=dnlwthrn]dgwright,
    Yes, the Light Brain is best if its close to the bulbs (manual says 12" or less from controller to bulbs). If you're running a setup similar to scar's with two of the pond lights on the handlebars, you could pick up a cheap plastic "box" from radioshack to mount the Light Brain in. Mount the switch to it, run the wires through it, and you should be fine (if you're worried about water penetration, seal the wire holes with silicone caulk).

    I'm still sitting on my stuff.

    dnlwthrn,
    I'm still waiting on my stuff to arrive . . .the plan is to mount the Lightbrain on the stem, and run a double light setup similar to Scar's. I would like to mount a switch that I can hit with my thumb, but I haven't found the right switch yet. I'm looking at some momentary right-angle tact switches, but they are so small, I'm not sure how they will work in practice. Found a few larger switches in Mouser, Digikey, etc. that may work. None of the batteryspace switches appear to be momentary. Another option is to mount the switch on the Lightbrain board. Since that would be located on the stem, it would be awkward to change light levels. I need to talk to Lightbrain. As I have never ridden trails at night, I don't know whether I will be changing light levels all the time, or 1-2 times in 2 hours. Look forward to seeing your housing fabrication.

  96. #96
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    The only downside I see to mounting the switch in the same housing as the light brain is that you'd have to take your hand off the bar to adjust light. That, and to dim the light you need to hold the button down for a sec or so... I haven't been able to find many momentary switches either for our application, so right now I'm just using a simple one from radioshack that will be mounted in the housing.
    I'm trying right now to get some basic photos of the setup (from my phone, so they'll suck) as well as a quick video showing the way the light brain works (also from camera phone). Maybe this will help to clear things up a little... Will post them when I get them uploaded.

  97. #97
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    Here's a quick video showing how the lightbrain works with my setup.

    <embed width="430" height="389" type="application/x-shockwave-flash" wmode="transparent" src="http://s147.photobucket.com/player.swf?file=http://vid147.photobucket.com/albums/r288/dnlwthrn/030607_11291.flv"></embed>

    And here's a photo of the same:


    Sorry for the poor quality, all I had to work with was my cell phone...

    The video stopped right as I was turning th light off. If you haven't looked into the Lightbrain, here's how the chip works: You press the button to turn it on (lowest power), then press momentarily for each step up to full power. To turn down/off, you hold down the button till it reaches the desired state. To turn off, you press and hold the button again after it gets to the lowest power setting.

  98. #98
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    Baulz - The outer diameter of the MR11 bulbs are quite a bit smaller than the inside diameter of the housing. The plastic lens that comes with the light has a "pocket" that holds the MR11 bulb in place. Without the plastic lens the bulb will be able to move around a lot. With the plastic lens at 14.4 volts, it will start to melt with the heat produced by the MR11 bulb and no water (i.e. pond) covering it to cool it. Without the plastic lens, the outer ring will have nothing to seal up against. You could always try just replacing the MR11 bulb with one of yours and use the plastic lens, might not get that hot at 7.2 volts. Hope that helps.

  99. #99
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    Quote Originally Posted by scar
    Baulz - The outer diameter of the MR11 bulbs are quite a bit smaller than the inside diameter of the housing. The plastic lens that comes with the light has a "pocket" that holds the MR11 bulb in place. Without the plastic lens the bulb will be able to move around a lot. With the plastic lens at 14.4 volts, it will start to melt with the heat produced by the MR11 bulb and no water (i.e. pond) covering it to cool it. Without the plastic lens, the outer ring will have nothing to seal up against. You could always try just replacing the MR11 bulb with one of yours and use the plastic lens, might not get that hot at 7.2 volts. Hope that helps.
    Thanks Scar. Have to order a few things from batteryspace so will be adding some bulbs as well.

    Would probably get the same amount of heat with 7.2v as it is still a 20% over-volt. I have melted plastic with bulbs before, so would prefer to avoid a repeat.

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    scar - Concerning the size of the battery pack.......Layout 6 AA's end to end then add a inch or so. I carry it in my nomad pack and drape the chord over my shoulder. The switch just kinda hangs in front. Used to have a bar mounted switch, but when it comes to riding around with wires dangling, a little as 2 inches too long or short of chord can really suck. I may have a better solution to a battery pack. I made the mistake of clicking a link to that online battery store. The 10,000mah D cells are out now. ( its been over a year since I checked.) Thats like 4 AA's, so I will order 4 to relpace my helmet pack and if they can deliver the amps like the AA's can, man, that would be good. It then would take 12 D cells to replace the halogen pack because you need 12 inline for the voltage, and that would be like 48 AA's, some serious runtime. Serious weight too, though. Oh well, seeing on a dark trail is more important to me than lugging around the batteries. I'm leaving now on a small epic.

    dnlwthrn - Thats one clean setup you have. Love the connectors to the bulbs I could never find. Great video too. I must take a que from you and copy that. You did that with your phone? I can IR to my PDA with special software I need to find. Then from PDA to computer, easy. Anything special I need to know? Because as simple and even low quality your video was, it was great. Oh, a great source for those DC coiled stretchy wires is your local thrift shop, 2nd hand store, or whatever. Mine is Value Village with tons of car adapters for 99 cents each. That Light Brain may even fit in a gutted shell of some adapter you may find.

    Now the video won't play for me....I did this AM. I swear, software is like a new chain with a old cassette, works for a sec then chain jumps, works for a sec then chain jumps, and so on.
    Sorry about the subject change in the thread. Now I'm gone riding.
    Last edited by UrbanPounder; 03-07-2007 at 10:34 PM.

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