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  1. #1
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    Homebrew battery packs for Magicshine P7

    I'm looking at the option of DIYing a battery pack or two for my Magicshine. I know GeoManGear sell replacement packs for ~$40 + $29 UK shipping (+ £import tax?) but I can get 18650 cells with free shipping from somewhere like DX and solder up my own packs for mush less.

    I haven't opened up my original battery pack to see if the cells are protected, I think there is some kind of curcuitry in the battery pack if I recall pictures from somewhere on this forum correctly?

    My setup with original light and battery pack will cut the light when the battery runs too low. Is this protection in the battery pack or does the constant current driver circuit in the lamp cut the power when it can't maintain the current? If so I should be relatively ok to run four protected cells in a homemade battery and this might even work with the original charger?

    Don't suppose anyone knows where I can get connectors that will mate with the supplied ones? If not I'll replace the lot with something like this

  2. #2
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    The driver board in the light head does shut the light off a little below 5volts. I don't know if that's by design or if the circuit just doesn't function below 5 volts. It's also turns the indicator light on the back of the light head from green to red at 6.8v.

    Personally, I don't like discharging li-ion batteries below 3v per cell. So for a 7.4v pack like the magicshine uses, I would set the driver in lighthead to shut off at 6v. The low battery indicator coming on at 6.8v is about right in my opinion. Since I can't change the cutoff voltage on the magicshine, I turn if off shortly after the low battery indicator turns red.

    I haven't taken the MS battery pack apart myself, but from pictures I've seen it looks like it has a fairly standard protection PCB. They almost always shut the pack down if any single cell drops down to 2.5v. Since the magicshine light head cuts off at such a low voltage, the battery protection PCB will likely cutoff first in most cases.

    You really shouldn't use un-protected li-ion cells in a multi-cell battery pack. Protection PCBs monitor the voltage for both an upper and lower limit for every single cell individually. It also monitors and limits pack charge and discharge current. If you rely solely on the light driver board for the low voltage cutoff, then you won't detect when a single cell drops too low. This happens when the pack becomes unbalanced which is pretty typical when a pack nears the end of its life. You can also buy standard protection PCBs cheaply, so there really isn't any reason not to build them into your battery pack.

  3. #3
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    Thnaks for the information. I intend to have this unit helmet mounted so I won't be able to turn the light off after the indicator turns red wethout a complex arrangement of mirrors

    I've just been searching for protection boards for the battery pack. I couldn't find much in the way of boards specifically for a 2x2 series/parallel setup. If each cell has over-discharge protection then it wil shut down and I would presume the other cell in the parallel pair would quickly discharge as it is taking the whole load and then also cut-out too which would effectively turn the pack off?

    Hmm, just thought I may be being dense here. With two cells wired in parallel with no significant resistance in the wiring there is no way to monitor the individual cells voltage outside the cells? Won't the voltage across both cells be the same? A board for a 7.4v (2 cells in series) pack would do the job of cutting the whole pack current when one parallel pair voltage drops below threshold. Is this any different from just using protected cells?

    I'm guessing multiple 2x2 packs would be preferable to a 3 parallel x 2 series combination for better run time from a battery pack protection point of view. At least I've learned from reading posts here not to try and solder the cells like I used to when I raced RC cars using Sanyo SCR and SCRC cells way back

  4. #4
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    Yes, a 2 cell protection PCB is what you need. Personally, I'd go with multiple packs over building a 2x3 pack.

  5. #5
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    Don't count out the battery holders. There are at least two of them from members here. I think one seller is from the UK. That way you can use individual cells protected or unprotected. If I remember correctly they have 4 and 6 cell versions that would work well with this light. This also allows for the cells to be charged separately for maximum safety.

    If you do build a pack it's best to use unprotected cells and a protection board for the pack.

    As far as soldering goes, it is not recommended. However, if you look you will find a few who have done it successfully. The key is to sand the soldering area just prior to fluxing it and soldering with a high wattage iron. I may give it a try. I'm also trying to get a tab welding setup going with a couple of 1 farad car audio caps that I have.

    This is good place for the protection boards. Unfortunately for those across the pond it is in the US.

    2 Cell pack boards -> http://www.batteryspace.com/pcbfor72v74vpack.aspx

    All boards -> http://www.batteryspace.com/pcmforli...terypacks.aspx

  6. #6
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    I don't see any problem with building a 3x2 or even a 4x2 pack if you want more run time. I have 2,4, and 6 cell 7.4 v packs that can be used interchangeably between my lights. The 2 cell was intended for a simple single emitter R2 I built, but, now I've found I get a solid two hour run time on my 3xR2 at 700ma. I can run the whole setup on the helmet without any wires and get just enough run time for short club rides. If I know I'll be out longer I grab one of the other, larger packs. The 2 cell packs also make a great, lightweight "backup" battery in case of emergencies.

    As for building, you definitely want to build in the PCB protection. Like McGayver said, you don't want to rely on protected cells for your packs.

    I had an old Li-Ion pack die and all my knowledge comes from rebuilding the pack with new cells using the old PCB's and poly switch. I am in no way an expert, but, my batteries work and I haven't caught on fire...yet.

    The pack I had was a 2x3 setup the used a small PCB for each pair of cells. So, there were 3 PCB's inside the pack and the P+/P- leads (3 each) were soldered to the output cable and shrink-wrapped. The PCB's were very similar to this one. You might be able to use one PCB designed for multiple cells, but, this is the configuration I've seen and use. It works well. The beauty of this PCB is you can use it for any 2x battery pack you want to build. Simply slap 2 more cells into your brick and increase your run time.

  7. #7
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    Do you recommend a single PCB for a 2s4p 14.8 v pack made from batteries salvaged from a fine, working order laptop that died from unrelated causes?
    Wrecker of fine things

  8. #8
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    Quote Originally Posted by 02Slayer
    Do you recommend a single PCB for a 2s4p 14.8 v pack made from batteries salvaged from a fine, working order laptop that died from unrelated causes?
    Is this the PCB from the laptop battery pack?

    Like I said before, I've only seen the inside of one pre-made pack and it used a PCB for each pair of cells. This is what I know will work, so, I don't mess with the formula. Li-Ion's have a nasty reputation for catching on fire if not handled properly. I don't want to find out the hard way I wired a pack wrong. Go with what you know is my motto.

    If you look at PBC's on Batteryspace, they suggest one for each group of batteries used in series. 1 PCB+2 cells for 7.4v, 1 PCB+3 cells for 11.1 and 1 PCB+4 cells for 14.8v. However, they have an 8 cell, 9600mAh pack that uses only one PCB. This is contrary to the "for use with two cells" description listed in the specs page. Although, if this pack only uses one PCB, it must work. I just don't know for certain.

    Hopefully, some guru with tons of battery building experience will chime in and enlighten all of us.

  9. #9
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    Thanks, I agree about the safety thing with these batteries, which is why I'm trying to be cautious. I now have a couple of these boards from BS;
    http://www.batteryspace.com/pcbfor14...agesocket.aspx
    They seem like a safe way to go, but I wonder how much safer individual batts would be w/ each having its own protection in a neat basic battery holder. Then charge them in an appropriate charger after a ride. The method you are using seems very sound. The pack I have is already attached to a harness with all the right connection in the right places to go right on that little board. I got the recommended BS charger too. Theres a board on the pack now, but it seems to have the connections for the computer pins wired onto it. It'd be cool to just use that board but I don't know enough about how the computer uses the power to understand what the various pin connectors are for. Plus, I already have these PCBs and they "should" work.
    Wrecker of fine things

  10. #10
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    I have one of those 14.8 and an 11.1 board as well. I haven't used them yet though. I bought them for a project and decided to use boost drivers instead. This allows me to use 7.4v packs for all my lights. Just made life a little easier.

    Individual cells in a holder is certainly an option. Some of the guys around here have been making some nice holders that can be configured different ways. That makes things very convenient. The ability to easily swap out dead cells is also nice. However, I like to tinker with this stuff so rebuilding a pack isn't a big deal to me. Also,I already have several chargers for the packs I make and don't need more stuff cluttering up my already messy work bench.

    As for the board out of the computer, I wouldn't use it if you don't have a schematic. If you do want to try it out, cycle it a few times on a flame retardant test bed and monitor the temperature. If it doesn't heat up too much or burst into a flaming inferno, you'll probably be safe. Take some pics and post up your findings.

  11. #11
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    Thanks wrench177, good to hear the 3x2 should be a safe build. I'm not sure if I'll use a battery holder but I'll stick with that protection configuration of a 7.4v series board per pair of cells.

    With an extra pair of cells in the 3x2 compared to the supplied 2x2 configuration, the current drain charging the pack together would be higher than the charger was intended for. What are the chances of the supplied 8.5v 1800ma charger working with a 3x2 pack? There should be no problems using it with an equivalent homebrew 2x2 pack should there? I may order one of those flame-retardant bags from BatterySpace at the same time as the protection boards, just in case...

  12. #12
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    Quote Originally Posted by agarthetiger
    Thanks wrench177, good to hear the 3x2 should be a safe build. I'm not sure if I'll use a battery holder but I'll stick with that protection configuration of a 7.4v series board per pair of cells.

    With an extra pair of cells in the 3x2 compared to the supplied 2x2 configuration, the current drain charging the pack together would be higher than the charger was intended for. What are the chances of the supplied 8.5v 1800ma charger working with a 3x2 pack? There should be no problems using it with an equivalent homebrew 2x2 pack should there? I may order one of those flame-retardant bags from BatterySpace at the same time as the protection boards, just in case...
    The charger "should" be fine. However, you don't know the quality of its construction. 1.8A output simply means it'll charge faster than a 1A charger. I have two 1A chargers and they charge all my packs, 2,4 and 6 cell without any problem. At 1A the 6 cell packs take longer to charge, but, I kinda prefer a slightly lower amperage when charging. This heats up the cells less and may help prolong their life.

    Now, I had a Marwi NightPro HID and went through 3 of their chargers. I assume it was poorly built, couldn't handle charging the 8 cell pack....whatever. Every replacement they sent me died within the first couple charges. Finally, I got a fairly robust charger from BatterySpace and never had the problem again. That's why I say the 1.8A MagicShine charger "might" work. 6 cells may be too much for it to handle. It is a pretty small charger, charging at a high rate and several people have report failures right out of the box. It's an inexpensive light for a reason. Corners had to have been cut somewhere.

  13. #13
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    I'm picking up a DX light and would like to build a spare 4 cell battery. I plan to use protected cells and charge them individually. Do the batteries need to run in series or parallel for these lights?

  14. #14
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    You need 2S2P battery configuration for MS light to run from 4 LiIon cells.

  15. #15
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    Holders for 18650

    Hi, I sell some 4X holders that would probably work well for you.

    Wire them as you need, and use protected cells if you are worried that you will run the pack low. That easy.

    Replace worn out cells as the fail, keep the long term cost low ...check em out below

  16. #16
    viva la v-brakes!
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    This is a little OT but you guys seem to know what you're talking about so I thought I could ask here:

    Last night my wife had an incident where her battery pack for her Magicshine light got caught up in her front wheel and was torn apart. It looks like all of the pieces are still there but, well, its in pieces. I am sure I can solder the wires back together, but I unsure how to connect the cells together to form the battery. I know that soldering is not safe, and it looks like they were maybe pressed together before. Is this something I could do (safely) in my shop if I am careful with a vice or tapping with hammer and pick? Could I get away with just taping everything together tightly, or would the connections break regularly?

    sdnative, I am probably going to get some of your holders to use with some other cells I have left over from another light. What else would I need to complete that project?
    Attached Thumbnails Attached Thumbnails Homebrew battery packs for Magicshine P7-img_0332.jpg  

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  17. #17
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    I would think that what you are calling "pressed together" is actually spot welds.

  18. #18
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    The solder tabs have been torn away from the cells. I wouldn't recommend trying to re-solder them unless you are VERY confident in your skills. If you decide to rebuild, scuff up the tabs with a file or Dremel. Clean any oil off with alcohol. Carefully do the same on the battery ends. Pre-tin the tabs and quickly try to solder them back into place. The battery will act as a heat sink and will work against you, that's why it's not advisable to solder without pre-attached tabs. People have the tendency to heat the battery too long and nasty things can happen.

    DO NOT try to re-attach the tabs using the "pick & hammer" method you mentioned. They were originally attached using a mini spot welder and that's why you see the holes in the tabs. A pick & hammer will only destroy the cells.

    Using the cells in a battery holder would work, however, they are probably not protected cells. That's what the PCB is for. If you go this route, you need to be extra careful with the cells.

  19. #19
    viva la v-brakes!
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    Quote Originally Posted by gmcttr
    I would think that what you are calling "pressed together" is actually spot welds.
    This is what it looks like so you tell me. Assuming this is spot welding, is there any other way to attach these without soldering? I am NOT very confident in my skills and I have a cheap soldering iron which takes forever to heat up the solder.
    Attached Thumbnails Attached Thumbnails Homebrew battery packs for Magicshine P7-img_0336.jpg  

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  20. #20
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    Why not try some conductive epoxy?


  21. #21
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    Take it to a shop that has a spot welder. Like Batterysource here in sunny Pensacola.

  22. #22
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    Awesome. I was hoping something like that existed. Is this something I can get at Radio Shack or do I have to special order from someplace like where your link sends me?

    Getting back to the battery holders, how do I know if the cells are protected or not? sdnative: do your cell holders have or work with a PCB (Protected Circuit Board?)
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    That conductive epoxy looks like it would do the trick, but ouch, that stuff is expensive. If you can't find it cheaper I'd seriously consider dropping the 35 bucks for a new battery pack. At least that way you know it'll work.

  24. #24
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    Quote Originally Posted by FishMan473
    sdnative, I am probably going to get some of your holders to use with some other cells I have left over from another light. What else would I need to complete that project?
    Man, bummer. Apparently that is the number 1 cause of night riding accidents (I hear the word "lawsuits" instead of "accidents" in that sentence) ....according to my Mountain Bike Action Mag connection. I beefed up my velcro on my DIY kits right after that chat.

    All you will need is the original battery wire that runs from the battery pack to the headlamp. You can likely de-solder it from the PCB.

    My experience with those spot weld tabs is that with a good pair of pliars you can pull them off w/o much of an issue. Be forwarned that there may be charge protection that was internally built into that pack. You may need another individual cell charger as opposed to simply plugging my holder into the old charger. May need it ....I dunno 100% here.

    Good luck!

    PS, I now have two types of 4 cell holders, 2's back to back , and flat in a row 4.


  25. #25
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    If you are worried about the safety of cheap Chinese Li-Ion batteries, a 6 series AA NiMh battery should work. The newer LSD NiMh batteries should run the light for about 1.5 hours, you might get 2 hours from higher capacity non-LSD cells. I'd hesitate to go to an 8 cell pack without modding the driver in the light. Mine came with a 10 volt input capacitor installed (which is kind of marginal for 7.4 volt Li-Ion batteries, but that's how they keep the price low).

    Personally, after taking apart the battery pack, and the charger, I'd never leave these plugged in overnight. Unless it was out on the driveway under an overturned metal bucket. Some of my cells showed clear signs of corrosion, and the charger gets pretty darn hot (not UL approved by a long shot). Good luck explaining to your insurance company how you were using a non approved Li-Ion charger when your house burned down, if you don't sleep thru it.

    Mark

  26. #26
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    Just get a new battery pack. Geomangear.com is one source.

    To reuse your cells you will have to buy a battery holder (or expensive epoxy) that cost 1/2 as much as a new battery pack, play games with cell protection and charging (maybe buy a new individual cell charger), have additional downtime, etc.

    It's just not worth it in my opinion.

  27. #27
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    I just got my magic shine and have a question that I'll ask here instead of starting a new thread.

    I need more burn time - 8 hours or more on high would be good. Is there a ready made battery for sale someplace that will work? Should I just buy two more battery packs from geoman? Should I try and make my own (I'm clueless about all the technical jargon y'all are using above)?
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  28. #28
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    Quote Originally Posted by driftwood
    I just got my magic shine and have a question that I'll ask here instead of starting a new thread.

    I need more burn time - 8 hours or more on high would be good. Is there a ready made battery for sale someplace that will work? Should I just buy two more battery packs from geoman? Should I try and make my own (I'm clueless about all the technical jargon y'all are using above)?
    I don't think you'll do much better cost wise than getting additional battery packs from geoman. If you're only running one light, getting a second one so you can run both a bar and helmet light will also help out. With a bar and helmet light, I rarely run them on high. That's the great thing about LED lights, they get a good bit more efficient running at lower power. If you run the magicshine on medium, you'll get more than half the light on less than half the power usage. I can measure the current draw on medium and give you an estimated run time....but it should be pretty long. In situations where you don't need as much light, such as a long climb or a fireroad climb, you can save power by switching to low or even turning one of them off. So 2 magicshine lights plus one additional battery pack would probably be a good setup for a ride where you needed 8 hours of light. It would also give you a better backup capability in case one of the lights failed.

    As an interesting coincidence, someone just forwarded me an e-mail yesterday that I believe is from you and probably related to this query........

  29. #29
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    For the price Geoman has a great option for a second battery pack. The time and effort not to mention the potential for mistakes makes the cost to buy a second pack off geoman a deal.

  30. #30
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    7.2v NiMH for the Magicshine

    I have just recieved my DX helmet version Magicshine and was also wondering about extra battery options.

    They specify that the battery voltage is 8.4v which i am assuming is the fully charged voltage of the 2s2p Li-ion pack.
    Now i thought that Li cells were 3.7v.... 2 in series is 7.4V, nominal.

    When I was down at Jaycar buying some extra wire and connectors (so that i can actually mount the thing on my helmet!) I noticed, for not a bad price, some 6 cell, 7.2V 3ah NiMH RC car packs . (You know, those old school "grasshopper" types they used to make with NiCd.)

    Although the rated voltage is lower would this be a problem in driving the light?

    The amp-hour is a little lower, (4.4 vs 3.0) but with the NiMH I probably dont have to worry about discharge levels as much as the factory pack and would be a good second battery to have for the longer rides, If i could get an hour extra out of it that would get me home.

    I am also guessing that a fully charged NiMH pack will have a higher measured voltage than its rating, at least for a few minutes of use.

    Neil.

  31. #31
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    New question here. Purchasing ready made battery packs for extended 8hr high setting run times

    Quote Originally Posted by driftwood
    I just got my magic shine and have a question that I'll ask here instead of starting a new thread.

    I need more burn time - 8 hours or more on high would be good. Is there a ready made battery for sale someplace that will work? Should I just buy two more battery packs from geoman? Should I try and make my own (I'm clueless about all the technical jargon y'all are using above)?
    The associated high current drain required for running the Magicshine MJ-808 for eight hours continuously on its high setting would require getting a rather high current amperage rated 7.4VDC external lithium ion battery pack like this; link posted/provided below:

    http://www.batteryspace.com/polymerl...-techplug.aspx

    This very high current external lithium ion battery pack from the folks over at batteryspace already comes preconfigured with the trail tec type of connectors as well as a nice external enclosure also as well.

    The price of the external battery pack is also competitive at $179.50 for 186.48watt/hours of power(7.4VDC times 25.2aH equals 186.48watt/hours)

    That prices out to a very competitive only 96cents per watt/hour(179.50 divided by 186.48watt/hours equals 96cents per watt/hour)

    For example, in proprietary (Cygolite, Lupine, Niteflux) hi intensity LED lighting systems it is not uncommon to be paying expensive premiums for replacement rechargeable lithium ion battery packs.

    To better help illustrate/clarify this not so obvious and subtle point, see the example supplied below for a Cygolit TridenX series Trion 600/Niteflux Photon Max Extreme(these lights have been selected as they are considered "state of the art" delivering very high levels of superior "lumens per dollar" value to the potential bicycle lighting systems consumer); links supplied below:

    Cygolite Trion600 product page description info :

    http://www.cygolite.com/products/new.../trion600.html

    Cygolite Trion600 main replacment rechargeable lithium ion battery pack:

    http://www.shop.cygolite.com/product...&categoryId=62

    Amazon sourced Cygolite Trion600 main replacement rechargeable lithium ion battery pack:

    http://www.amazon.com/CygoLite-7-6V-...6303063&sr=8-4

    The Cygolite Trion600 main replacement rechargeable lithium ion battery pack is basically a 7.6VDC rechargeable lithium ion battery delivering 2.6aH of battery capacity for $63.60 on amazon.

    So running the same above analysis, 7.4VDC times 2.6aH equals 19.24watt/hours

    Thus $63.60 divided by 19.24 watt/hours equals $3.30watt/hour

    Now compare this with the above 96cents per watt hour of the Magicshine MJ-808 and its non-proprietary open/universal external rechargeable lithium ion battery pack swap in via the trail tech connectors and its any wonder why my preference and bias is towards the more practical and cost efficient universal external rechargeable lithium ion battery pack model being offered in the Magicshine MJ-808 P7 Led Lightset Kit offering.

    Bottom line it appears from the above paragraph rational/logical explanation and insightful cost analysis that one in fact gets about at least three times more external rechargeable lithium ion battery pack run times for the same amount of monies expended which is definitely something to be cheering about.

    Niteflux Photon Max Extreme 20 product page description info:

    http://www.niteflux.com/Products_photonMaxExtreme.aspx

    Niteflux Photon Max Extreme 20 main replacment rechargeable lithium ion battery pack:

    http://www.niteflux.com/BuyBatteries.aspx

    The Niteflux Photon Max Extreme 20 main replacement rechargeable lithium ion battery pack is basically a 14.4VDC rechargeable lithium ion battery delivering 2.2aH of battery capacity for $215.99.

    So running the same above analysis, 14.4VDC times 2.2aH equals 31.68watt/hours

    Thus $215.99 divided by 31.68 watt/hours equals $6.81watt/hour

    Now compare this with the above 96cents per watt hour of the Magicshine MJ-808 and its non-proprietary open/universal external rechargeable lithium ion battery pack swap in via the trail tech connectors and its any wonder why my preference and bias is towards the more practical and cost efficient universal external rechargeable lithium ion battery pack model being offered in the Magicshine MJ-808 P7 Led Lightset Kit offering.

    Bottom line it appears from the above paragraph rational/logical explanation and insightful cost analysis that one in fact gets about at least six times more external rechargeable lithium ion battery pack run times for the same amount of monies expended which is definitely something to be cheering about.

    It is in fact definitely most advantagous to be having the added capability of running and staying in high power lumen intensity setting for three to six times longer running times than normal as opposed to not having the option at all.

    So please, before deciding on purchasing a potential bicycle lighting please do ones due diligence and homework and above analysis. Now if you are ok with the the above inherent additional battery premium costs so be it; for those Cygolite/Niteflux/Lupine fanboys out there, which of course also include the rechargeable lithium ion batteries accelerated replacement due to now known about "lithium ion aging"(explained in following below paragraphs-all the way to end) effects(basically need changing out every three years).

    Just also be aware of the total battery run times will be at least three to six times greater via the P7 Led Magicshine MJ-808 Lightset as explained in the analytical process explained and detailed above all throughout the rechargeable lithium ion battery packs anticipated "lithium ion aged" affected lifetime.

    Also remember, if you do decide to purchase this lithium ion battery or any lithium ion battery in general; that all lithium ion batteries experience what is called an "aging" effect which is not a widely publicized unique drawback of the Lithium Ion battery; is that its life span is dependant upon aging from time of manufacturing (shelf life) regardless of whether it was charged, and not just on the number of charge/discharge cycles.

    At a 100% charge level, a typical Lithium Ion that is full most of the time at 25 degrees C(77degrees F), will irreversibly lose approximately 20% permanent total capacity per year. This capacity begins from the time it was manufactured, and occurs even when the rechargeable lithium ion battery is unused.

    This phenomenon is called "aging of lithium ion" rechargeable cells and is an issue that is often ignored entirely. Apparently, the lithium ion cell capacity loss manifests itself in increased lithium ion cell internal resistance caused via internal oxidation "rusting" of the the lithium ion rechargeable cell and is unfortunately unavoidable.

    Eventually, this lithium ion rechargeable cell resistance reaches a point where the lithium ion pack can no longer deliver the stored energy although the battery may still have ample charge. Unfortunately there are no remedies to restore a lithium ion rechargeable cell once it is worn out.

    To help illustrate and now apply this newfound knowledge of what is called the "aging" effect on rechargeable lithium ion battery packs and further help to explain this often entirely ignored point see below one example for a 4.4aH external lithium ion battery pack and the other one a 25.2aH external lithium ion battery pack; which should prove interesting as we now know about the undesirable "effects" of rechargeable lithium ion battery aging:

    4.4aH divided by 1.20 equals 3.66aH after one year use
    3.66aH divided by 1.20 equals 3.05aH after two years use
    3.05aH divided by 1.20 equals 2.54aH after three years use
    2.54aH divided by 1.20 equals 2.12aH after four years use
    2.12aH divided by 1.20 equals 1.77aH after five years use
    1.77aH divided by 1.20 equals 1.47aH after six years use
    1.47aH divided by 1.20 equals 1.23aH after seven years use
    1.23aH divided by 1.20 equals 1.02aH after eight years use

    25.2aH divided by 1.20 equals 21.0aH after one year use
    21.0aH divided by 1.20 equals 17.5aH after two years use
    17.5aH divided by 1.20 equals 14.58aH after three years use
    14.58aH divided by 1.20 equals 12.15aH after four years use
    12.15aH divided by 1.20 equals 10.12aH after five years use
    10.12aH divided by 1.20 equals 8.44aH after six years use
    8.44aH divided by 1.20 equals 7.03aH after seven years use
    7.03aH divided by 1.20 equals 5.86aH after eight years use
    5.86aH divided by 1.20 equals 4.88aH after nine years use
    4.88aH divided by 1.20 equals 4.06aH after ten years use
    4.06aH divided by 1.20 equals 3.39aH after eleven years use
    3.39aH divided by 1.20 equals 2.83aH after twelve years use
    2.83aH divided by 1.20 equals 2.36aH after thirteen years use
    2.36aH divided by 1.20 equals 1.96aH after fourteen years use
    1.96aH divided by 1.20 equals 1.63aH after fifteen years use
    1.63aH divided by 1.20 equals 1.36aH after sixteen years use
    1.36aH divided by 1.20 equals 1.14aH after seventeen years use

    As we can see from the two above timeline illustration/scenarios the effects of lithium ion "aging" effects on toal lightset runtime.

    Notice in particular the 4.4aH rechargeable lithium ion battery pack after three years only has only 2.5aH left in battery capacity.

    Also notice in particular the 8.8aH rechargeable lithium ion battery pack after the same three years has 14.58aH left in battery capacity, and in fact does not fall to the approximately same 2.5aH battery capacity level(4.4aH battery pack) for about another additional ten years; for a net combined total of thirteen years effective use from the same external rechargeable lithium ion battery pack.

    The two major "take away points" here is, get a slightly plus sized capacity rated lithium ion battery for your particular battery running times application(its simply put, an energy storage device/tool; size it accordingly); you get what you pay for and also use but don't abuse your lithium ion battery pack so that it can take care of your battery run applications in an optimal manner by not running the battery beyond its more than 60% of total rated capacity(4400maH times 0.60 equals 2640maH) before recharging it.

    cheers
    Last edited by daniel58; 10-23-2009 at 06:49 AM. Reason: Edited/Updated new information and amplifying commentary feedback

  32. #32
    drunken pirate
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    Thanks for the info and advice. Two magicshines does seem to make the most sense, I suppose, but I am very happy with the output of just one on my helmet and was thinking that a big battery is all I need. I can buy two additional batteries and that would be more than enough burn time for me for less than the cost of two lights.... decisions, decisions...

    MtbMacgyver, the forwarded query you got was not from me but I very much appreciate your thoughtful response.
    More Trails, Not Less

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  33. #33
    GeoMan
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    Quote Originally Posted by FishMan473
    This is a little OT but you guys seem to know what you're talking about so I thought I could ask here:

    Last night my wife had an incident where her battery pack for her Magicshine light got caught up in her front wheel and was torn apart. It looks like all of the pieces are still there but, well, its in pieces. I am sure I can solder the wires back together, but I unsure how to connect the cells together to form the battery. I know that soldering is not safe, and it looks like they were maybe pressed together before. Is this something I could do (safely) in my shop if I am careful with a vice or tapping with hammer and pick? Could I get away with just taping everything together tightly, or would the connections break regularly?

    sdnative, I am probably going to get some of your holders to use with some other cells I have left over from another light. What else would I need to complete that project?
    Email GeoMan (click here). There might be an easier solution... Hehe.

    Geo
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  34. #34
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    New question here.

    Quote Originally Posted by driftwood
    Thanks for the info and advice. Two magicshines does seem to make the most sense, I suppose, but I am very happy with the output of just one on my helmet and was thinking that a big battery is all I need. I can buy two additional batteries and that would be more than enough burn time for me for less than the cost of two lights.... decisions, decisions...

    MtbMacgyver, the forwarded query you got was not from me but I very much appreciate your thoughtful response.
    Remember one can also use of course Nickel metal hydride battery pack(low cost) or Nickel cadmium battery pack(ultra low cost) also as well; so long as it adds up to 7.2VDC and has sufficient amperage to get the illumination job done that fits your needs and preference battery chemistry battery pack its all good if it extends the run times.

    cheers

  35. #35
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    I bought a magicshine lighthead alone, and am using it with my 7.4v LiPo RC car batteries (yeah, I know its not protected by PCB, I just unplug it after a few hours of riding). Frankkly, I have a high end charger and many batteries sitting around, so I thought why not use em. Specifically, I am using this battery here.
    i'm no pro at this, just reading a lot on line and trying to safely experiment. So far its working great.
    Questions for the battery/electronics experts.... magicshine description on geoman's site says "Digital Regulated 2400mA Current Output". I've been trying to estimate runtime for my 5AH and 8AH LiPo packs.... well I hooked up the 5AH battery to the lighthead with my multimeter in between and measured a steady 1.4 amps.

    So, is this possible, given that light description would indicate its supposed to draw 2.4 amps?
    How can manufacturer claim 3+ hour runtime from 4x18650 batteries, a pack of probably 4400mah, if its drawing 2.4 amps?
    Finally, if 1.4amp draw is accurate, then my 5AH battery should last 5AH divided by 1.4amps= 3.57 hours, right?

    Thanks for everyone's advice & feedback.

    PS- I am eager to buy a 2nd lighthead and run BOTH in parallel circuit to my 8AH battery....

  36. #36
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    Quote Originally Posted by rfxc
    I bought a magicshine lighthead alone, and am using it with my 7.4v LiPo RC car batteries

    ...


    Questions for the battery/electronics experts.... magicshine description on geoman's site says "Digital Regulated 2400mA Current Output". I've been trying to estimate runtime for my 5AH and 8AH LiPo packs.... well I hooked up the 5AH battery to the lighthead with my multimeter in between and measured a steady 1.4 amps.
    The led is driven at 2.4A, ~3.5V, so the 1.4A, 7.4V from your battery gets converted to that in the driver. Volts go down, current goes up.

  37. #37
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    New question here.

    Quote Originally Posted by rfxc
    I bought a magicshine lighthead alone, and am using it with my 7.4v LiPo RC car batteries (yeah, I know its not protected by PCB, I just unplug it after a few hours of riding). Frankkly, I have a high end charger and many batteries sitting around, so I thought why not use em. Specifically, I am using this battery here.
    i'm no pro at this, just reading a lot on line and trying to safely experiment. So far its working great.
    Questions for the battery/electronics experts.... magicshine description on geoman's site says "Digital Regulated 2400mA Current Output". I've been trying to estimate runtime for my 5AH and 8AH LiPo packs.... well I hooked up the 5AH battery to the lighthead with my multimeter in between and measured a steady 1.4 amps.

    So, is this possible, given that light description would indicate its supposed to draw 2.4 amps?
    How can manufacturer claim 3+ hour runtime from 4x18650 batteries, a pack of probably 4400mah, if its drawing 2.4 amps?
    Finally, if 1.4amp draw is accurate, then my 5AH battery should last 5AH divided by 1.4amps= 3.57 hours, right?

    Thanks for everyone's advice & feedback.

    PS- I am eager to buy a 2nd lighthead and run BOTH in parallel circuit to my 8AH battery....
    Yes that is right, your multimeter is giving the correct lowdown at about 1.4amps on high setting with a 4.4aH battery pack about three hours run time approximately(if needed see my comprehensive post on this topic and others; as I go through a comprehensive derivation from provided source information-its quite a comprehensive read but its thorough; and should assist in helping you understand what is going on as you are experimenting and getting ready to run your 2nd lighthead in parallel with a external battery)

    Ultimate bike light search

    What is a source of common confusion, is in fact it is quite common for LED lightsets to use what is called a "buck" LED driver that brings the actual 7.4VDC battery voltage down to what the LED source actually uses which is usually at a much lower voltage and in the process it also correspondingly delivers a specified regulated higher current that stays constant even as the battery voltage goes down; that is why the MS lightset's led lumen output can maintain a constant lumen output at 200lumen for low, 500lumen for medium and about 600lumen or so for high intensity setting.

    Yes that is right on ones 5ah battery that should last a little over three hours.

    Remember, Lithium Ion polymer chemistry deteriorates at a rate of twenty percent per year of total battery capacity(if needed see my comprehensive post regarding this)

    Homebrew battery packs for Magicshine P7

    Also, if one is charging a high amperage battery pack that is nearly entirely drained you may want to reference this post for additional information:

    http://www.candlepowerforums.com/vb/...&postcount=152

    I also go into as well some other considerations when considering a double lightset, you may want to reference this post for additional information:

    http://www.candlepowerforums.com/vb/...&postcount=150

    cheers to more lumens utilizing a double lighthead
    Last edited by daniel58; 10-29-2009 at 08:19 PM.

  38. #38
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    Thanks znomit & daniel58! Good advice, thanks for checking my sanity.

    Interesting, I have the 3 mode light (hi-low-flash) and on low mode it is still quite bright, and draws only .5 amps. Makes me wonder whether i could mount the lighthead AND small battery on the helmet, use only low mode, with an approx 2000mah battery and still get 3-4 hr runtime.

  39. #39
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    New question here. Reply feedback followup

    Quote Originally Posted by rfxc
    Thanks znomit & daniel58! Good advice, thanks for checking my sanity.

    Interesting, I have the 3 mode light (hi-low-flash) and on low mode it is still quite bright, and draws only .5 amps. Makes me wonder whether i could mount the lighthead AND small battery on the helmet, use only low mode, with an approx 2000mah battery and still get 3-4 hr runtime.
    Yes, that is right it should be close to 440ma to 500ma ball park on low setting and would be equivalent to lets say something in lumen intensity to a dinotte 200lumen LED lighthead engine; which should be probably ok for conservatively riding ones bicycle 10mph or so at night and for higher speed downhill passes use the high setting sparingly.

    Usually with a helmet mounting one can get away with placing the minute and small lightweight battery pack in ones rear cycling jersey pockets as the battery pack is not much larger than a powerbar. If one needs an extension cable because it is to short to reach; Geomangear carries them at:

    http://www.geomangear.com/index.php?...roducts_id=152

    Geomangear of course also carries, spare replacement Lithium Ion 4.4aH batteries also as well which are nice, small in profile and lightweight at:

    http://www.geomangear.com/index.php?...roducts_id=141

    cheers to more lumens via double LED lightheads
    Last edited by daniel58; 10-29-2009 at 08:49 PM.

  40. #40
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    I'd just like to publicly thank GeoMan for sending us a replacement battery pack for the one my wife broke. That was above and beyond. Thanks.

    PS: She's using it right now, riding home from the end of the year meeting for her ladies MTB team.
    =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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  41. #41
    GeoMan
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    Quote Originally Posted by FishMan473
    I'd just like to publicly thank GeoMan for sending us a replacement battery pack for the one my wife broke. That was above and beyond. Thanks.

    PS: She's using it right now, riding home from the end of the year meeting for her ladies MTB team.
    Ah, thanks. Nice to hear when your efforts are appreciated!

    Hope you wife had a great ride!

    Best,

    Geo
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  42. #42
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    Idea! battery bottle holder

    battery bottle holder,

    here is one I did,

    to reuse the existing magicshine battery's
    Attached Thumbnails Attached Thumbnails Homebrew battery packs for Magicshine P7-imgp8460_magicshine_2xbatterie_holder.jpg  

    ----
    DIY battery + light working on it

  43. #43
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    Quote Originally Posted by FishMan473
    I'd just like to publicly thank GeoMan for sending us a replacement battery pack for the one my wife broke. That was above and beyond. Thanks.

    PS: She's using it right now, riding home from the end of the year meeting for her ladies MTB team.
    This kinda service with this product's value per dollar (most bicycle accesory parts and the industry-in-general don't seem to get how tough times are right now & are still asking the same margins) is too amazing not to go ahead and upgrade my lighting system so I can get a flashing mode for safety in traffic. I will be ordering one from u soon geo. (Even though my old HID L&M Arc is still working fine.)

  44. #44
    www.hahntronix.com
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    Hey mtb_robs-x,

    Quote Originally Posted by mtb_robs-x
    battery bottle holder,

    here is one I did,

    to reuse the existing magicshine battery's

    That's a real nice looking bottle you modded. The results look really nice. Would you mind telling where you bought it?

    Thanks,

    Mark
    Nimium est melior!

  45. #45
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    ...Scun.thorpe, UK

  46. #46
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    Mark, they are available on ebay .....
    .
    BBB Tools & Tubes Can/ Bottle Screw Top

    ...Scun.thorpe, UK

  47. #47
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    I'm building myself a couple 2 cell packs for my Magicshine for either my short commutes to work (35-40 minutes) or for helmet mounting. My 18650 cells are not protected. I bought these protection circuits:

    http://www.all-battery.com/pcbfor74v...865032056.aspx

    I'm having some trouble with the wiring.

    I have the 2 cells wired in series. I have connected the PCB B+ to the positive end of one cell, the B- to the negative end of the other cell, and the COM to the brass tab that I soldered between the other ends of the cells. When I measure the voltage between the P+ and P- on the circuit board, I get nothing. I currently have the P+ going to the positive lead on the light connector, and the B- going to the negative lead. I think I'm probably defeating the protection functions of the board with this wiring, but that's the only place I get 2 cell voltage (8.4v). I get 1 cell voltage (4.2v) between the P+ and the COM, and 1 cell voltage between the P- and the COM.

    The cells were fully charged when I started. I used one of the DSD chargers to help ensure that the cells were relatively well balanced before beginning. The light works, and has some decent run time (2,800mah cells), but I'm concerned about the protection. Could the board be duff? I have 3 more here. I had planned on building 3 more packs, but I now know that my protection boards are meant for 2 cell packs. I was going to build another 2 cell pack, as well as a 4 cell and a 6 cell (8,400 mah for dual bar mounted lights).

    Help!

  48. #48
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    couple toughts/tips

    after you get the pcb on, you'd need to plug it in a charger, aka apply voltage,
    to activate the circuit.
    not recommending putting the cells together , unless they are matched and balanced,
    that requires some know how and a fancy charger.
    I'd recommend, get the packs prebuild, and go from there.
    and at some point, replace that ms cheap charger, with a better quality one.
    one thing you'd forgot, instead of the cooper bar,... what I don't recommend, since the soldering requires more/exessive heat,... is to put a fuse in-between.
    don't forget to seal the battery.
    other tip, you can still do 2cell packs and put those afterwards together, again the pre - after matching is important, before sealing. 6-8cell don't recommend doing yourself.
    if you need a larger pack, you can contact me.
    note: larger packs require , new charger, for charge time and safty.
    cheers, Rob
    ----
    DIY battery + light working on it

  49. #49
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    Thanks for the feedback Rob. When I get home, I'll move the negative wire from the B- back to the P- and then plug it into my charger.

    I have been using the Tenergy smart charger (http://www.all-battery.com/universal...v1-4cells.aspx) for my 14.8v LiPo pack which I built for my Nite Rider HID light about 2 years ago. My charger has a switch for 3.7, 7.4, 11.1 and 14.7v and charges at 500mah. I'm certain that I'll have no trouble with a home built 6 cell pack. I'm not after perfect balance/performance, and with all the cells being fully charged before assembly, I'll be satisfied with the level of balance that I achieve. I have 3 of the DSD chargers, so when I assemble the pack, the charge will be at the same level for all the cells.

    As far as the brass tab, I tinned the brass and the end of the cell with solder, and my iron is an adjustable temperature controlled iron (Pace). I have plenty of fast heat, and lots of practice soldering. Very little heat is transfered to the internals of the battery.

  50. #50
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    That did the trick. Both my 2 cell packs are in the Plasti-Dip stage right now. They're working great so far.

  51. #51
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    I just want to point out something for those that were mentioning the rate of reduction in capacity for li-ion cells. If you look here you can see that if lithium ion cells are stored at 40% charge and stored at 0C (or basically close to refrigerated temps) you can see as little as 2% reduction in capacity over a year. This is of course ignoring the reduction in capacity from charge cycles but it should take a couple hundred of those before you really have to start worrying about significant losses.

    So, use your battery then throw in in the fridge till you charge up for next time and you'll be in good shape. If you think you totally drained it then charge it for just a little while then throw in the fridge. Avoid moisture damage by single or double ziplock bagging.

    20% reduction in charge seems to only come from storing fully charged at room temps so just don't do that! Also, leaving li-ion cells in a car on a sunny day can do a lot of damage.

  52. #52
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    Can you plasti-dip the stock magicshine battery to make it waterproof? It rains a ton here and someone mentioned frying theirs in the rain on one of the threads.
    "It looks flexy"

  53. #53
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    Quote Originally Posted by gticlay
    Can you plasti-dip the stock magicshine battery to make it waterproof? It rains a ton here and someone mentioned frying theirs in the rain on one of the threads.
    Yes: Plastic dip battery waterproofing (for MagicShine, etc)

  54. #54
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    Maybe a dumb question, but if I bought those red protected 3000mah cells, can I just solder them into a pack since they are individually protected?
    "It looks flexy"

  55. #55
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    Quote Originally Posted by gticlay
    Maybe a dumb question, but if I bought those red protected 3000mah cells, can I just solder them into a pack since they are individually protected?

    You can solder them into a pack but then you would not be able to charge them up

    better to get one of the holders around on here and put a cable on it to suit the MS light.
    still recomend to keep the beggers dry though .

  56. #56
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    Quote Originally Posted by troutie-mtb
    You can solder them into a pack but then you would not be able to charge them up

    better to get one of the holders around on here and put a cable on it to suit the MS light.
    still recomend to keep the beggers dry though .
    Huh? Wouldn't you just plug them into the Magicshine charger? Those are soldered into a pack.
    "It looks flexy"

  57. #57
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    Quote Originally Posted by gticlay
    Huh? Wouldn't you just plug them into the Magicshine charger? Those are soldered into a pack.

    Yes you could but if you used protected cells each cell has a circuit on it that would dislike the 8.4 volts the MX charger would be trying to put into the pack .

    you need to use unprotected cells and put the correct protection circuit on the whole pack .

  58. #58
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    Quote Originally Posted by troutie-mtb
    Yes you could but if you used protected cells each cell has a circuit on it that would dislike the 8.4 volts the MX charger would be trying to put into the pack .

    you need to use unprotected cells and put the correct protection circuit on the whole pack .
    Um, not quite. Since two 18650 cells will be wired in series (plus N pairs in parallel to that), each cell will "see" only half voltage of the charger's output. So, protection circuit of each cell will be quite happy with the input and will have no reason to interfere in the charging cycle until the voltage of that individual cell will reach the protection circuit's upper voltage threshold (but, by that time the charger itself will probably already "shut itself off" since the two-cells-in-series pair will hopefully reach charger's upper voltage threshold before that).

    In short - you can safely use MS charger to charge "home-made" packs of protected 18650 cells, as long as the cells are wired in 2SnP configuration.

  59. #59
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    Quote Originally Posted by ortelius
    Um, not quite. Since two 18650 cells will be wired in series (plus N pairs in parallel to that), each cell will "see" only half voltage of the charger's output. So, protection circuit of each cell will be quite happy with the input and will have no reason to interfere in the charging cycle until the voltage of that individual cell will reach the protection circuit's upper voltage threshold (but, by that time the charger itself will probably already "shut itself off" since the two-cells-in-series pair will hopefully reach charger's upper voltage threshold before that).

    In short - you can safely use MS charger to charge "home-made" packs of protected 18650 cells, as long as the cells are wired in 2SnP configuration.
    Technically true, but there are some pitfalls in practice.

    The biggest potential problem is all the Trustfire protected cells I've tested, have a very low upper protection limit of 4.15V. Since this is below the typical charger voltage regulation of 4.2V per cell, the batteries tend to shut down as soon as the constant voltage stage of the charge cycle starts. That means they'll only reach 60-70% of full charge. If folks have other brands of protected cells and have tested them, I'd really like to hear the upper and lower limits on the protection PCB.

    The other problem is how well the cells are matched. Since they are loose cells, if you mix and match different ones you'll end up with the protection PCB on the weaker cell ending the charge very early because it's voltage will go up really quickly compared to the stronger cell during the current limited stage of the charge. Even if you keep the same set of cells together, you may run into balance problems because the cells aren't likely from the same manufacturer batch and date.

  60. #60
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    Thanks for the corrections folks
    so what if it was only a 2 s cell pack

  61. #61
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    So the magicshine runs off of 2x2 packs. I don't know anything about current battery technology, but matched packs and a full discharge with an individual cell discharger was the bomb when I raced for an R/C Car factory team. 7 cell modified with a 13x2 Reedy motor baby!
    Last edited by gticlay; 01-05-2010 at 12:14 AM.
    "It looks flexy"

  62. #62
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    Quote Originally Posted by gticlay
    So the magicshine runs off of 2x2 packs. I don't know anything about current battery technology, but matched packs and a full discharge with an individual cell discharger was the bomb when I raced for an R/C Car factory team. 7 cell modified with a 13x2 Reedy motor baby!
    Yes, it's a 2x2 pack.

    Li-ion batteries have very different characteristics than Nicad or Nimh batteries. Running them all way down is about the worst thing you can do to them. They will last far longer if only partially discharged and charged. They also have their max capacity when brand new and lose a tiny bit of capacity with every cycle. So cycling them will never increase capacity, only reduce it.

    Here's an interesting piece of info. If your light has much longer runtime than you need for typical rides, then charge your li-ion packs up to 3.9 volts / cell instead of the typical 4.2 volts / cell. They'll only have about 75% of the stated capacity of the battery available, but you'll get more than 2x more cycles from the battery. If you do that and store the batteries in the fridge at 40% charge whenever they aren't being used for long periods. They'll last virtually forever. You can still charge them to 4.2 volts / cell on the occasions when you need the full runtime,.

    Unfortunately, you need a charger that'll let you control the voltage limits to do that. I've never really found what I consider a really good flexible li-ion charger. I charge mine off a nice variable power supply where I can set the voltage and current limits. But, you should only do that if you're meticulous about setting it correctly every time. I've come so close to building my own li-ion charger so many times.... I just need to stop building new lights and then I'd have time to build some nice chargers.

  63. #63
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    Quote Originally Posted by troutie-mtb
    Thanks for the corrections folks
    so what if it was only a 2 s cell pack
    Like most things, there are lots of competing tradeoffs. Ironically, if you do build packs out of individually protected cells, you'll probably have the best luck with 2s2p or 2s3p configurations. That's because the parallel banks of cells will more or less average out and be less likely to be significantly weaker or stronger than the other parallel bank. Where as a 2 cell 2s pack will be hit or miss just based on how well the 2 cells happen to be matched. You can of course make it work well if you profile the cells and make sure you use well matched ones together.

    Because of this, it even matters to some extent the position of each cell in the pack if you're keeping a set of cells together. Lets say you have a set of 4 cells and 2 of them are a little weaker and 2 a little stronger. if you have a weak and strong cell together in each parallel string the pack will work well. If the 2 weak ones end up together in a bank the pack won't work as well.

    when you get into deeper parallel configuration, 4p and more, you start to run into bigger issues with how evenly the current divides between the parallel cells.

    when you get into longer serial configuration, 3s and more, you start to run into bigger issues with the voltage balance between the cells.

    How much of an issue all of this becomes depends a lot on how hard you're pushing the packs. If you only really need a moderate amount of the pack's capacity, say 65%, then you're a lot less likely to run into issues. Because most of these issue are pronounced at the limits. But, in general, I think if you're using battery holders you'll probably have better results if you charge the cells individually and keep similar cells together. By similar I mean same age and same number of cycles.

  64. #64
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    The battery for my magicshine stopped working about a week after a ride where it got wet (no other rides after). It worked for about a week after the ride and then just cut out.
    The battery connections were all corroded, so i've taken them all off and now have the batteries all separate.
    Dont know if i should have tried this, but i got a wire from each end of each battery and touched the wire to the lighthead plug connections, nothing happens (with any of the batteries)
    Should the unit light up when i do this?
    Where shall i go from here with the battery pack in pieces....?

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    Joe,
    You can post it to me to look over if you want, please make sure it is safely wrapped up before posting though, if all else fails I should be able to build you a compatible battery for it.

    Smudge

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    Thanks smudgemtb, thats a good offer. I'd rather have a go at fixing it myself (if anyone can guide me in the right direction) first of all. If that dosnt work, i'll send you a PM.
    Cheers
    Joe

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    Quote Originally Posted by joehspicer@msn.com
    The battery for my magicshine stopped working about a week after a ride where it got wet (no other rides after). It worked for about a week after the ride and then just cut out.
    The battery connections were all corroded, so i've taken them all off and now have the batteries all separate.
    Dont know if i should have tried this, but i got a wire from each end of each battery and touched the wire to the lighthead plug connections, nothing happens (with any of the batteries)
    Should the unit light up when i do this?
    Where shall i go from here with the battery pack in pieces....?
    If you were connecting a single cell to the magicshine light, then no it will not light up. The voltage of a single cell is below the minimum voltage for the driver. The normal arrangement for this battery is 2 parallel strings of 2 cells in series (2s2p). That gives a nominal pack voltage of 7.4 volts. The driver in the magicshine stops functioning around 5 volts.

    I'm not quite sure what you mean by "I've taken them all off". If you mean you've disconnect the spot welds for the connecting straps, then it's going to be hard to safely reassemble the pack. Unless you happen to have a battery spot welder. Soldering to li-ion cells is not really a safe thing to do. Some good picture of the state of the pieces would be a good way of providing the info that would be needed for folks to offer advice.

  68. #68
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    Quote Originally Posted by joehspicer@msn.com
    Where shall i go from here with the battery pack in pieces....?
    Depending on your soldering skills you could go the holder route. This lets you use individual cells as opposed to a pack, which is nice as you can replace cells as they wear out ...which they will given just time. An option at least

    Read more here >>

    Good luck ~Chris

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    this one with the switch , is a 8 cell pack, build myself.
    if you want one , PM me.

    there is also one without the switch, taller one, where you can use 2 of you existing ms packs, just put them in, done.

    also working on a lupine battery bottle, improved version, with higher capacity,
    and faster charge time. PM if interested.

    working on batteries and LED lights.
    from mtb to military use
    LED's from mtb , street commuter to police/military use. 500 to 3500 lumen.


    Quote Originally Posted by HEY HEY ITS HENDO
    ----
    DIY battery + light working on it

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    Thanks for the help guys, its coming in pretty usefull.
    I've borrowed a voltmeter, none of the batteries are giving a reading of more than 0.15v, does this mean the batteries just need charging, or theyre ruined?
    And the only charger i have that they'll fit in is designed for NiMH and NiCd batteries, will this be ok to use?.... whats the difference between this charger and Li-ion chargers?

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    If they're really at 0.15v then they're ruined.

    Nicad and Nimh battery chargers are constant current chargers. Li-ion charger are primarily constant voltage along with a current limit for the first stage of the charge. Putting a li-ion battery in a nicad / nimh charger will not work and is very dangerous. It could very well result in a fire.

  72. #72
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    use a car charger, it does charge it really fast,...

    if you got a MS battery, you should have the li-ion charger,...
    so why would you use a nicd or nimh charger ??

    wonder why, dell is charging an arm and leg for new batteries,...
    why the mac has in sealed integrated one,...
    why they start hussling, everybody on the airport,... how much lithium you got,...
    you are only allowed, oh, couple grams, 1/2 ounce tops,... gee



    Quote Originally Posted by joehspicer@msn.com
    Thanks for the help guys, its coming in pretty usefull.
    I've borrowed a voltmeter, none of the batteries are giving a reading of more than 0.15v, does this mean the batteries just need charging, or theyre ruined?
    And the only charger i have that they'll fit in is designed for NiMH and NiCd batteries, will this be ok to use?.... whats the difference between this charger and Li-ion chargers?
    ----
    DIY battery + light working on it

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    btw guys DX are now selling replacement battery packs (and a case) for these $30.

    I was going to build my own $20 for the 4 cells I wanted, extra $10 for the connector, charging curcuit and case... worth it imo. I'm now wondering about a 8 cell pack instead (because buying one is just too easy )

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