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  1. #1
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    Batteries, again

    Sorry but I find the need to discuss batteries yet again. I know, I know, hundreds of threads etc etc but with the lflex available and the best pairing being a single xml and single cell li-ion / li-po I've been looking for some 3.7v batteries.

    DX and KD obviously have loads of 18650 batteries and picking one out of the bunch as better quality than another is liking finding the proverbial needle. (happy for recommendations here people) and then you have to fashion a holder or get something like sdNatives and waterproof that

    Anyway what has got me thinking is lots of RC hobby places sell 2, 3 and 4 cell batteries with reasonable capacity but I can't find a single cell one above about 850mAh and that obviously just doesn't cut it for run times. Why can't I find them? Where are they all, surely thses bigger packs are made up of 2, 3 or 4 cells of capacities between 2000mAh and 2600mAh so why can't I find any?

    I'm trying to avoid places like batteryspace because of the now prohibitive shipping costs.

    If I buy a 3 cell battery like this one from hobbyking can I pull it apart to get three 2650mAh 3.7v batteries? what do I need to be careful of? What do i need to do to get three individual, usable batteries?

    Any other suggestions?

    FTR this is the only large capacity single cell I can find

  2. #2
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    I think that's because most 3.7 v rc machines (helis, plane, commands) are very sensitive to weight or have very low consumption.

    You can go the other way around. Buy 4 850mAh cells and put them together as a large 3,7v 3.4 mAh pack

    I made a few batteries using a single 18650, water proof and its rather easy and cheap to build. Even if you use a pair of protected 18650, you can put together a 3,7v +-5000 mAh pack without any holder at all and that can be charged by a "vulgar" 18650 charger without problems with balancing ( not sure about the balancing but if I'm wrong someone will set me right )

  3. #3
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    emu26, I think you can pull apart an RC battery with no problems at all. I've never done it as I've needed my packs intact, but I can't think of any reason you couldn't. The only thing you'll need to do is disconnect the balancing leads. Of course they aren't protected, but then the LFlex should take care of that.

    The reason you can't find large capacity single cells is as bravellir says. There are very few motors which run off a single lipo, and those that do are very limited in the power they generate and therefore the lifting capability they have. Therefore any single cells need to be very lightweight - the likes of the Silverlit Picoo Z use a 3.7V but it's absolutely minute. Most motors for larger helicopters use 7.4V or 11.1V as a minimum, simply to provide the power required.

    By the way, I've been using quite a few of the black and red Trustfires from DX and they've been pretty good.

  4. #4
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    Yes, you can pull a larger RC pack apart. It's really very easy. You just have to be really careful not to short the cells during the process. The lflex really doesn't provide battery protection. Personally, I would spend the few bucks for a protection PCB to put inside the pack. You can also take something like a 3s 2200mah pack and reconfigure it to a 3p 6600mah pack.

    Personally, I would also want to put lipo cells in some kind of hard case for bike light use, since they are very susceptible to puncture damage. Actually, I use 18650 for bike light use because of the physical protection of the metal case. I use lipo packs for my RC planes and helicopters. I've been using the Panasonic 2900mah 18650 cells with my lflex and XML single light wired into a 2p pack which makes it a 3.7v 5800mah pack. So far I'm really happy with that setup. Extremely small and light and gives runtime close to 2 hours on full and 4 hours at 1.4amp which is a very use-able amount of light. It's light enough that I'm experimenting with the battery on the helmet, which is something I never thought I would do.

  5. #5
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    7,4 V 5000 mAh LiPo:
    http://hobbyking.com/hobbyking/store...idProduct=9437
    There are 2 long flat 3,7 V 5000 mAh batterys inside. BUT they're without protection.

  6. #6
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    I'm not sure how much they will charge for shipping to the lucky country, but these are looking interesting to me.

    http://www.allelectronics.com/make-a...BATTERY/1.html
    Last edited by Vancbiker; 02-28-2011 at 07:54 AM.

  7. #7
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    Quote Originally Posted by Vancbiker
    I'm not sure how they will charge for shipping to the lucky country, but theses are looking interesting to me.

    http://www.allelectronics.com/make-a...BATTERY/1.html
    I've ordered lots of stuff from All Electronics in the past. They've been around forever and I have always been happy dealing with them. I don't know if they ship internationally or not.

    There isn't a bunch of detail in that spec sheet, but it sounds like the "charge control board" is simply a thermistor on the little connector PCB soldered to the leads of the cell. There is a third wire in the pack connector that I assume is connected to thermistor such that the host device or a protection PCB can measure cell temperature. A high quality protection PCB will use the thermistor to prevent pack charging when the pack is too cold or hot.

  8. #8
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    I have some 18650s on order from AW to use in my lFlex build. I think they were ~$19 each, with a total of $4.50 in shipping (no haz-mat fees).

    There are supposed to be built with the new 2900 mAh Panasonic 18650 along with the PCB. I've used AW 17670s in the past with good results, and I expect the same here.

    I really wanted to go with a Li-Po pack, but the weight and hassle of physically protecting the from puncture made the single 18650 make better sense in this instance.

    I am under the impression, that if you are quick with it, that you can solder leads directly to the positive pip, and to the back plate of the PCB (seen as the negative post of the cell) of these protected 18650. Obviously, one could also damage the cells or PCB with careless soldering, but I think (hope?) I'm going to be OK.

  9. #9
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    I've ordered this one to rip it apart for single cells.

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    I believe all-battery.com doesn't charge the ridiculous haz-mat fees which batteryspace does, and their prices are comparable.

    If you want to go with DX, the Trustfire True 2400 cells with the red and black label are generally considered the best they have to offer.

    Like MtbMcGuyver, I also prefer 18650's over Li-po's because of the protection from the steel can. I use a 4-cell pack which is hot-melt glued together, then dipped three times in Plasti-Dip to give it a tough, waterproof coating. I use a TwoFish LockBlock to strap it underneath my handlebars.

  11. #11
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    I'm happy with the 6 Uniquefire unprotected 2500mAh cells I got from DX, capacities were in the 2250-2290mAh range, which isn't bad. I bought 6 grey 2500mAh Trustfires, again from DX, whose capacities were 2230-2270mAh. Both types charge and discharge fine at high rates on my AC6 charger, so they seem decent quality, although time will tell. I'm using Digikey 18650 holders, soon to be balance wired and plastidipped.

    One thing that seems clear from CPF about DX batteries is that there's no point paying for the higher capacities as the fudge/ lie factor is even higher. If you need >2500mAh real capacity, you're better off with Sanyo/NCR/Samsung cells.

  12. #12
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    Thanks for all the replies and recommendations.

    As always tends to be the case when post a "Where can I find" type thread, I find. Did another fleabay search and came with a couple of options similar to this

    http://cgi.ebay.com.au/Team-SILVERBA...#ht_2178wt_905

  13. #13
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    Free woldwide shipping, bigger than 18650 but a couple of these in parallel should do the job:

    http://www.4sevens.com/product_info....oducts_id=2585

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    Quote Originally Posted by bravellir
    .... you can put together a 3,7v +-5000 mAh pack without any holder at all
    Care to share some details?


    It's the "without any holder at all" part I'm interested in...

  15. #15
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    Here's a battery pack from All-battery online for a reasonable price, wired and protected:

    http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT


    I just got one of these holders, wired for 1S2P with protection: They appear to be identical to the Batteryspace ones:
    http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT

    and I plan to use the black-and-red Trustfire Dx batteries, once they arrive. I also have some of the unprotected Digikey battery holders, but the protected ones are smaller and pre-wired.

    I just couldn't source any plasti-dip near where I am in Caledon, and the shipping was murderous online, so I got some self fusing silicone tape and will dunk or paint on liquid electrical tape which I did manage to find.
    Last edited by Ofroad'bent; 03-01-2011 at 04:17 AM.

  16. #16
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    Quote Originally Posted by langen
    Care to share some details?


    It's the "without any holder at all" part I'm interested in...
    What I mean is that since you don't need to worry about balancing, you can get 2 protected 18650 cells, wired them in paralell, solder, glue and water proof them with plasti-dip or tape and you can charge the pack with a simple 18650 charger .
    You dont need the holder because you don't have to pull them apart from the pack to charge.

    I did a few of those packs.

    Simple Light - "The Miner" build videos
    Here ( video 3,4 and 5 ) you can see an example I did but with a single cell. You dont want the button if you are using the lflex.

  17. #17
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    Watch out for ordering battery holders from Digi-key if you're not in the US.

    I ordered a couple of Reginas and some $2 battery holders. The shipping was a horrific $35 on the first order, and they had the chutzpah to charge me another $30 to ship 2 Reginas. $65 shipping on a $9 order. Sigh- live and learn.

    The protected battery case I got on eBay was $10 including shipping, and it got here fast.
    That's the way to go.

  18. #18
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    Thanks for the info and feedback Ofroad'bent.

    If I were to use that holder can you use protected cells or should they be unprotected?

    If I were to tape and plastidip two cells into that holder what could I use to charge them? Do I need to be concerned about balancing cells in parallel as I would in series?

  19. #19
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    It's always been my understanding that parallel cells balance themselves.
    Look, whatever happens, don't fight the mountain.

  20. #20
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    I wasn't sure if it was possible for one to drain down or charge at a faster rate than the other and thus leading to problems

  21. #21
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    As long as they are the same capacity.
    It doesn't hurt if they are matched, same brand, model and from the same batch.
    I try to buy my cells in batches, and make my packs with cells from the same batch.
    I wouldn't mix and match brands/models though.
    Look, whatever happens, don't fight the mountain.

  22. #22
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    Quote Originally Posted by Ofroad'bent
    Here's a battery pack from All-battery online for a reasonable price, wired and protected:

    http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT


    I just got one of these holders, wired for 1S2P with protection: They appear to be identical to the Batteryspace ones:
    http://cgi.ebay.com.au/ws/eBayISAPI....=STRK:MEWAX:IT

    and I plan to use the black-and-red Trustfire Dx batteries, once they arrive. I also have some of the unprotected Digikey battery holders, but the protected ones are smaller and pre-wired.

    I just couldn't source any plasti-dip near where I am in Caledon, and the shipping was murderous online, so I got some self fusing silicone tape and will dunk or paint on liquid electrical tape which I did manage to find.
    mail order plastidip from here: http://www.caswellcanada.ca/shop/plastidip-products/

    they have it at Home Hardware, but it's something like $18/can

    For ground Canada Post shipping:
    For orders under $100 -- $14.00


    did have to buy 3 large cans of plastidip (don't stock anymore) to ease the shipping
    Last edited by oreophilus; 03-01-2011 at 11:59 PM.
    .

  23. #23
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    Quote Originally Posted by Ofroad'bent
    Watch out for ordering battery holders from Digi-key if you're not in the US.

    I ordered a couple of Reginas and some $2 battery holders. The shipping was a horrific $35 on the first order, and they had the chutzpah to charge me another $30 to ship 2 Reginas. $65 shipping on a $9 order. Sigh- live and learn.

    The protected battery case I got on eBay was $10 including shipping, and it got here fast.
    That's the way to go.
    you have to order from digikey.ca not digikey.com

    shipping is $8
    Attached Thumbnails Attached Thumbnails Batteries, again-digi.jpg  

    Batteries, again-digi-q.jpg  

    .

  24. #24
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    Quote Originally Posted by oreophilus
    you have to order from digikey.ca not digikey.com

    shipping is $8
    Aww, cr*p. I hadn't seen that. OK, maybe I'll try them again in the future, if I can't find something elsewhere.

    I should have mentioned that the second $30 was not a separate order, but simply 2 Reginas that were backordered. I thought it was particularly unreasonable to kill me on the shipping when it was their fault due to backorder. I've contacted them about this.

  25. #25
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    Quote Originally Posted by emu26
    Thanks for the info and feedback Ofroad'bent.

    If I were to use that holder can you use protected cells or should they be unprotected?

    If I were to tape and plastidip two cells into that holder what could I use to charge them? Do I need to be concerned about balancing cells in parallel as I would in series?
    This holder is the same protected one that Batteryspace sells, and shouldn't need protected cells. I happen to have protected cells on order for the Digikey holders.

    My plan for a charger is to modify a cheap charger like this:
    http://www.el34world.com/Misc/bike/BikesLights22.htm

    It's my understanding that balancing isn't as critical if they're in parallel, but I'm no expert.
    Also, if these cells go out of balance, it's a $5 replacement and a re-waterproofing job with no soldering.

  26. #26
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    Quote Originally Posted by oreophilus
    mail order plastidip from here: http://www.caswellcanada.ca/shop/plastidip-products/

    they have it at Home Hardware, but it's something like $18/can

    For ground Canada Post shipping:
    For orders under $100 -- $14.00
    Thanks. I was at 3 different Home Hardwares, and 2 Home Depots- none had it.
    The link you gave me is out of stock on black right now.
    I finally found a small jar on eBay for a reasonable shipping fee.

    Do you think I can use the Liquid Electrical Tape I have first as a waterproofer? It's supposed to be like a slightly thinner plasti-dip.

  27. #27
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    Quote Originally Posted by savagemann
    As long as they are the same capacity.
    It doesn't hurt if they are matched, same brand, model and from the same batch.
    I try to buy my cells in batches, and make my packs with cells from the same batch.
    I wouldn't mix and match brands/models though.

    Yes you would think capacity would have to be the same, but this is not correct, they can be different capacity's. Internal resistance and voltage is what you need to match up, why you would have different capacity's, I don't know, so really a mute point.

    What is most important is, BEFORE paralleling cells, you MUST voltage match to as close to each other as possible...the higher voltage cell will try to charge the lower voltage cell, the split second you parallel them up, as you know 30C cells pack a hell of a punch, and would melt the pins of a balance plugs (if used to parallel) with a big voltage difference between cells.

    IMO, lipo should allways be protected at a cell level, and one should never rely on LED driver alone for protection.

    If using parallel cells from RC pack, please balance to .01v with this, battery medic before paralling.

    sorry to butt in, but lets keep it safe guys....


    Ktronik

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    Interestingly enough there was some experimentation done on candlepowerforums which indicated the cells didn't need to be particularly well matched voltage-wise, at least not with 18650 cells. The guy started off with cells slightly out for experimentation, then half discharged one before connecting etc., measuring corrective currents between the cells. Unfortunately cpf is down at the moment so I can't link to it.

    Of course 30C cells have a significantly lower internal resistance than an 18650 so if using these then the corrective currents would be that much higher. Better to be safe than sorry, whatever the type of battery, and make sure the voltages are equal before connecting together in parallel.

  29. #29
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    Quote Originally Posted by mfj197
    Interestingly enough there was some experimentation done on candlepowerforums which indicated the cells didn't need to be particularly well matched voltage-wise, at least not with 18650 cells. The guy started off with cells slightly out for experimentation, then half discharged one before connecting etc., measuring corrective currents between the cells. Unfortunately cpf is down at the moment so I can't link to it.

    Of course 30C cells have a significantly lower internal resistance than an 18650 so if using these then the corrective currents would be that much higher. Better to be safe than sorry, whatever the type of battery, and make sure the voltages are equal before connecting together in parallel.

    Yep spot on w 18650 it does not matter as much, and in reality you would not have to be that anal with LIPOs, as I am with mine... Yes CPF is where I began, and such a wealth of info, 'sliverfox' is the MAN in the know when it comes to batts on CPF...

    interesting to note I have seen a weaker cell in a pack, infect the same parallel cell on the other pack, even with 4 parallel 4S pack, the same cell in each pack is affected, tihs can happen on a small scale to large scale, you would never know its there until you notice you got less cycles out of the pack, compared to another same type pack, with well ballanced cells, this effect is at a min...

    hope this helps


    K

  30. #30
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    But if you don't match up cells with the same capacity, aren't you basically losing performance/runtime, since the pack will be drained down to the lower capacity first?
    Then the cell with larger capacity will never run to it's full potential?
    Lets say you make a pack out of 18650 cells, 3s1p 11.1v
    You use 2 cells that are 2600 mAh and one cell that is 2200 mAh
    You will never run down that last 400mAh that is left in the other cells.
    Let me know if I'm wrong since this is how I understand it.

    Now, lets say we are making a 1s3p pack with the same batteries that I mentioned above, how does this effect the performance of the pack?

    Is it safe to say to charge all the cells before assembling into a pack?
    Thats what I usually do.
    Look, whatever happens, don't fight the mountain.

  31. #31
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    Since you all are on the battery subject. I have a Lupine 7.5ah 6 cell battery for my betty light that need replacing. What, if you would, suggest for replacement cells if you ae familiar with this light.

    Thx

  32. #32
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    Here is a 5000mAh 3.7V hardcase LiPo: http://www.venom-group.com/itemdesc.asp?ic=15036
    CNC LED light housing for DIY projects

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    Even better:
    http://www.himodel.com/electric/HiMo...rs_trucks.html

    http://hobbyking.com/hobbyking/store...idProduct=9967
    this one will give you 2 hardcase 3.7V batteries for a mere $27
    CNC LED light housing for DIY projects

  34. #34
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    Are you suggesting I use these ones as is or remove the cells and solder up th Lupine electronics that are apart of their (my) battery pack.

    I undrestand lupine has some preparatory protection electronics as part of their packs for the charger one that i use of their's, is this an issue at all that you know of ?

    Thx

  35. #35
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    Quote Originally Posted by savagemann
    But if you don't match up cells with the same capacity, aren't you basically losing performance/runtime, since the pack will be drained down to the lower capacity first?
    Then the cell with larger capacity will never run to it's full potential?
    Lets say you make a pack out of 18650 cells, 3s1p 11.1v
    You use 2 cells that are 2600 mAh and one cell that is 2200 mAh
    You will never run down that last 400mAh that is left in the other cells.
    Let me know if I'm wrong since this is how I understand it.

    Now, lets say we are making a 1s3p pack with the same batteries that I mentioned above, how does this effect the performance of the pack?

    Is it safe to say to charge all the cells before assembling into a pack?
    Thats what I usually do.
    your 100% right, it's a dumb thing to do, using diff capacitys... What I mean is if you did it, it won't blow up or anything and work fine, but yes you min capacity cell would dictate you overall capacity.

    When I get my pack, I check balance first, a pack w close voltages, say within .02 will be a great pack, that will go many cycles. A pack out of balance by .1v should be cycle charged a bit to massage the weaker cell... All ways ballance charge on first charge cycle. Then check internal resistance, again if close, it will be a good pack... This way I weed out any problems I may have in my packs... Less returns for me means happier customers

    hope this helps


    K

    I cycle charge and balance all packs before I use, I also check internal resistance... it's important too watch the cell voltages when they first charge

  36. #36
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    Sounds like some good stuff K.

    When I get a fresh batch of batteries, I will throw a meter on all of them, and sort them by which have the most similar voltage.
    Out of 20 batteries, I'll usually have 3 or 4 groups.
    I then build packs from the individual groups.
    After the pack is built I will balance charge it, run it down and check balance, then charge it again.
    It will usually hold a much tighter voltage after a couple of these cycles.

    It sounds like you are going through a similar process.
    I am just building lights for myself and all my buddies, and now all their buddies want lights..........I guess thats how it all starts.

    The hardest thing for me is finding time to build all of these lights.....= )
    I have a batch of 15 in the works right now. Phewww
    Look, whatever happens, don't fight the mountain.

  37. #37
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    Lol, your life sounds like mine!!! Fix bikes all day, build lights all night... Get fat from lack of riding...

    Hobby king has a charger, icharge 106b, that will mesure cell and pack internal resistance...it is the best way to see inside your cells, if you know what I
    mean...



    Quote Originally Posted by savagemann
    Sounds like some good stuff K.

    When I get a fresh batch of batteries, I will throw a meter on all of them, and sort them by which have the most similar voltage.
    Out of 20 batteries, I'll usually have 3 or 4 groups.
    I then build packs from the individual groups.
    After the pack is built I will balance charge it, run it down and check balance, then charge it again.
    It will usually hold a much tighter voltage after a couple of these cycles.

    It sounds like you are going through a similar process.
    I am just building lights for myself and all my buddies, and now all their buddies want lights..........I guess thats how it all starts.

    The hardest thing for me is finding time to build all of these lights.....= )
    I have a batch of 15 in the works right now. Phewww
    Last edited by ktronik; 03-04-2011 at 10:57 PM.

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    Quote Originally Posted by danaco
    Since you all are on the battery subject. I have a Lupine 7.5ah 6 cell battery for my betty light that need replacing. What, if you would, suggest for replacement cells if you ae familiar with this light.

    Thx
    The same tabbed Sanyo cells are for sale on ebay. Done mine, work awesomely.

  39. #39
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    If anyone has the time to put together a step by step "how to" guide to building battery packs, I'd sure appreciate it!!!!!

    I have the basic ideas, I'm just hesitant to solder the batteries. Also confused about which protection board goes with what volt batteries.

    A new thread sure would be sweet!!!!!!

  40. #40
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    OK for you guys, I have contacted my PCB protection supplier, to see if they have some good quality 5-10A PCM's for single cell lipos...

    Do you guys think that good quality, 3.6v PCM's would be needed?? or will you guys just buy the cheapo ones from DX??

    if they do I can offer 3.6v / 5Ahr batts with good protection, as well as 1.0-5.2Ahr 14.8v batts I all ready sell.

    They will come FUSED, in case the protection PCM fails, PCMed in cases the driver protection fails.

    So dual redundancy back up, then double wrapped in thick heat-shrink for puncher protection, water and dust ingress protection

    For the cheap arsed, you could use the DX 10A 3.6v PCM (cough cough read as 5A only one fet, so I am told)

    let me know what you think???

    K

  41. #41
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    That sounds interesting to me.
    I know my mate, that prompted me to start this thread in the first place, has already contacted you re getting one of the batteries you mentioned in a previous post.

    Great to see a local supplier

  42. #42
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    I could see getting some of these, but I would still waterproof them.

    I think if you offered them plasti-dipped as well as wrapped it would be an advantage for folks that can't do that.

  43. #43
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    Quote Originally Posted by Ofroad'bent
    I could see getting some of these, but I would still waterproof them.

    I think if you offered them plasti-dipped as well as wrapped it would be an advantage for folks that can't do that.

    All my batts are waterproof... I would not go diving with them, but I do have a 20M case if you do

    I think the dual heatsrink may be a bit more 'stabproof' than the plasti-dip...but I have not done a stab test...



    If you can charge your RC lipo on balance mode, or have a PCM wired to each cell to make sure one of your cell does not get over charged.


    WHY??

    the weaker or dud cell can easily be over charged, in a serial pack. (when not using balance mode on charger) the charger see only the whole pack, total voltage, so can't look after each cell. If the cell is over charged, it will 'vent with flame'

    When the charger is in balance mode, it see's all the cells and will stop charging the dud one, at the limit set in charger (normally 4.2v)

    OR run a PCM and it looks after the cells from over charge, over drain & short circuit.

    A $5-10 LIPO fire bag is also cheap insurance...

    K

  44. #44
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    K-tronic, did you ever get the battery packs for sale?

  45. #45
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    I have not got a PCM order together as of yet, but I did order 2/ hard case 5700mAh 1S battery's for a member, that I will build into 2 packs with a fuse ea (short circuit protection) and let the Lflex look after the over drain, and the charger the over charge. not totally ideal but till I get some 1S PCM's that the best I can do, as i can only get them in bigger lots...

    ktronik

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    K, one advantage of the single cell, single LED setup is that even if your customer's driver is not setup to cutoff at 3.0V, the light will be pretty dim below 2.8V or 2.7V, so they are likely to turn it off anyway.

    A downside of this dimming as the voltage drops, is that the PCB on my batteries cutoff at a lower voltage than they do at full load. I have noticed that at 1C loads, the PCBs will cut around 3.0V, but that at currents that are less than 50mA, the PCBs will let the current flow without tripping to 2.7V or lower.

    The dimming is a fortunate by-product in my case, as I cannot seem to get my low voltage cutoff or warning to work on my LFlex. In the spirit of full disclosure, I am a mere hobbyist when it comes to assembly techniques, PCB handling, and soldering, so there is a definite possibility that a stray static discharge or some other fault of mine took that particular sense resistor out; all of the other features and controls on the board works perfectly.

  47. #47
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    No good lflex not playn the game...

    As it comes disabled, you have turned it on in the program mode right?? Also do this, go into program mode and only adjust 5 (vstat) one click will do, then go out of program mode and test your warning/ cutoff again... Try that then get back to me. K

  48. #48
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    Cheers Kerry

    A big thanks to Ktronic for supplying the batteries for my single XML build, ordered and arrived within 3 days, fantastic service.

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    Although some may not like this way of doing things, I have always gone down to my local PC store, asked them for any old laptop battery packs that they intend to recycle and then get myself about 6 packs, come home, break them apart and take out all the good batteries (usually the ones reading around 3.7v or more) and put together my own packs.

    I have a decent charger for 7.4v & 14.8v and they work fine with the combinations I have put together.

    I have a 8 cell 7.4v pack that is good for 4hours on high for a Troutie Mini and a 12 cell 14.8v that is also good for around 4 hours on a Troutie 7UP.. been running batteries like this for a while and get approx 18months out of each set and then I just ditch them and start again - it costs nothing but my time.

  50. #50
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    IMHO, that is super bad!! Sure it works for you, but you have been lucky

    Series wired non matched cells are a mega NO NO, ask anyone in the bizz, it's a sure way to make fire, then on top of this you use old cells that will
    be tossed out, your crazy dude!!! Your girl will be pissed of then you burn the house down to save a few bucks!! Just buy new ones please
    everyone...

    Again this is MHO

    Ktronik


    Quote Originally Posted by EFMax
    Although some may not like this way of doing things, I have always gone down to my local PC store, asked them for any old laptop battery packs that they intend to recycle and then get myself about 6 packs, come home, break them apart and take out all the good batteries (usually the ones reading around 3.7v or more) and put together my own packs.

    I have a decent charger for 7.4v & 14.8v and they work fine with the combinations I have put together.

    I have a 8 cell 7.4v pack that is good for 4hours on high for a Troutie Mini and a 12 cell 14.8v that is also good for around 4 hours on a Troutie 7UP.. been running batteries like this for a while and get approx 18months out of each set and then I just ditch them and start again - it costs nothing but my time.
    Last edited by ktronik; 04-06-2011 at 04:07 AM.

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