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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 08:54 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 05:17 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; 03-02-2011 at 12:59 AM.
    .

  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

  28. #28
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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 11:57 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

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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

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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

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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.

  51. #51
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    I've been using batteries from thrown out laptop batteries for >6mths. Either charged individually or using balance wires, always in a LiPo sack. There's nothing inherently dangerous about those cells, they just have a lower remaining capacity than fresh bought cells, plus they're usually higher quality (LG, Samsung) than cheap cells from China.

    For me the downside is that you'll always get lower capacity (unless you're really lucky with what you find) for the same weight. Plus side is that they're free and you're keeping stuff out of landfill.

  52. #52
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    Sorry, but you guys just don't have enought time under your belts for any real testing

    voltage of a cell is different to internal resistance, if you re-match your old cells, for both your fine... As long as your running protection

    it's charging that's the biggest issue, a cell can show good voltage, but have high internal resistance built up over time, this will be charged with less overall capacity, sure it will look fine, and work fine, but it's not.

    When your charging your pack, the poor cell will charge up first, hitting 4.2v, but other cells keep charging, as they have not hit 4.2v... This is where the danger is, in a non protected pack you weaker cell will be overcharged, if you over charge a lipo/ion by 5-10% it may 'vent with flame'.

    If your gunna use old cells, you need to at least test voltage under load, if you can't check internal resistance, this is way better than just a voltage test, as a dud cell will/ can show good voltage and trick you.

    Your guys need to tell boh sides of the story, yes it worked for you, but his is the dangers blar blar, or newbys may get hurt... Oh wait a Minute, it's a fourm, that was I thinking...

    Ktronik

  53. #53
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    easy there sunshine.

    Anyone who's going to start taking apart Li-ion battery packs should know enough about what they're doing to know that there are risks involved. I shouldn't have to nanny people, they're responsible for themselves. I've also never, not on here or CPF, heard of anyone using recycled laptop cells that had an overcharging issue. Given the consequences of that happening, you'd think people would squawk about it if it had.

    Second, everyone that I know or have heard of using these cells either charges them singly or uses balance leads, as I stated in my post, which would obviate your main point about overcharging weak cells in series packs.

    As always, your mileage may vary, but kindly do not patronise me.

  54. #54
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    Quote Originally Posted by ktronik
    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
    Heheee sometimes histeria makes me smile and I appreciate (its your HO)... But the laptops are broken so the batteries get ditched and out of kindness to the planet they get separated and thrown away separately.. so I choose to get 8 or 12 Batteries that happen to be choosen from 60, those sixty are all made by either Sony or Panasonic (all the same style, same colour and who knows, maybe even the same batch numbers) and I pick the best of the bunch and wire them up in a series-parallel configuration and in the years that I have been doing this, not one single incident or even a hint of (have made up about 25 this way now for mates and their lights and their replacements and again - no trouble).. Li-ion are not the bad bad boys everyone screams about, even when unbalanced, slightly discharged or mildly overcharge (though I do you use quality smart chargers).. but I thank you for the warning and concern and I shall endaveour to be extra careful - as for cost, the same batteries of equal quality but new, in the UK would probably cost about £5 each and a lot more for better, which in itself is not a lot but 20x, for me is a saving worth making without loading the enivironment up with more purchase of stuff that is already available, a saving worth the effort..

  55. #55
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    Sorry to offend guys, not what I was after, I am a green nut my self, and have never owned a car, ride my bike every where...

    But really mostly newby would read these post to find out how to do things... I am about sharing, for the betterment of others.

    Hey I use a dynamo hub driven light on my bike... No batts at all!! ;-)

    k

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    I repect the fact that a newbie reading this thread might get the wrong impression about all of this and for that, then I stand up and say sorry.. sometimes it is too easy for me to make certain assumptions as I guess anyone mad enouch to rip apart a set of laptop batteries would be actually mad enough to know the rest of the story and as such be smart about wiring and the whole overcharging batteries. Personally I find the imports from China to not be all they claim to be and also the flip side, some of the more popular brands are expensive for what they are. It is fair to say that most laptop batteries makers actually do use some good quality cells to start with and if you get batteries from the same make of laptop maker, you can often get almost identical batteries from their packs..

    With so many lights now being made with under-discharge being built in to them and so many smart chargers taking care of the over-charge situation, that the risks on protected cells is so small it is "almost" completely safe - though caution and common sense must be observed.

  57. #57
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    I've been using these
    for a long time but now I've set my eyes on These new comers. High capacity , tabs, high discharge rate, reasonable weight, 1000 cycles, safer chemistry and a hard shell, all sound promising. Anyone has any experience on them?

  58. #58
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    Quote Originally Posted by manokaiser View Post
    I've been using these
    for a long time but now I've set my eyes on These new comers. High capacity , tabs, high discharge rate, reasonable weight, 1000 cycles, safer chemistry and a hard shell, all sound promising. Anyone has any experience on them?
    I picked up 6 of those 26650 cells a while back. So far so good. I'm really happy with them.
    Look, whatever happens, don't fight the mountain.

  59. #59
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    Quote Originally Posted by savagemann View Post
    I picked up 6 of those 26650 cells a while back. So far so good. I'm really happy with them.
    Did Batteryspace charge the extra hazardous shipping fee for these?
    Which PCB did you use for protection?

  60. #60
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    Nope, they are UN Approved NDGR. I think that stands for Non Dangerous Ground.
    I'm not using a protection board. I guess you could say I am "winging it".
    Look, whatever happens, don't fight the mountain.

  61. #61
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    Sony LR18650 3000mAh

    http://www.kaidomain.com/ProductDeta...oductId=10683#

    What about these? I can't find any testimonials yet, but if they hold true to their capacity they seem to be good option for value/capacity/weight

  62. #62
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    Quote Originally Posted by savagemann View Post
    I picked up 6 of those 26650 cells a while back. So far so good. I'm really happy with them.
    How do you charge these 26650 cells? Can you use a standard Li-Ion chrger?

  63. #63
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    Here's a find- I contacted this eBay vendor, and he can make up 1S2P or 2S1P battery packs using the high-end Sanyo cells if you specify when you purchase.
    Looks a good deal at $25 including shipping for a 2-cell battery, and no huge hazardous charge.
    I'll get one and test capacity with my Turnigy charger.

    I'll waterproof with heat-shrink and plasti-dip, and adapt the 5.5mm connector to seal to a Magicshine male with some more heat-shrink tubing.

    http://cgi.ebay.com/ws/eBayISAPI.dll...04542012194821

  64. #64
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    Looks a good deal at $25 including shipping for a 2-cell battery, and no huge hazardous charge.
    How is that a Good Deal? For 25$? It's more than double the price with less capacity than these for example

    Making a pack out of them is just so simple I can't justify the extra cost, or am I missing something here?

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    Can anyone tell me why LiPo battery packs aren't being more prevalently used? They seem to work very well for RC vehicles....why don't more folks use them for bike light battery packs? I know they need to be carefully balanced when charged, but again, the RC world seems to have embraced them. Why haven't we?

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    Quote Originally Posted by manokaiser View Post
    How is that a Good Deal? For 25$? It's more than double the price with less capacity than these for example
    Good find, if those are real Sony and really 3000mAh. Anybody have experience already or feel lucky?

  67. #67
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    Quote Originally Posted by manokaiser View Post
    How is that a Good Deal? For 25$? It's more than double the price with less capacity than these for example

    Making a pack out of them is just so simple I can't justify the extra cost, or am I missing something here?
    I've made battery packs out of similar batteries. By the time you add the shipping, battery holder, PCM and connector, it adds up. Either that or you wait forever for free shipping from Dealextreme. Also, this complete battery pack is easier for newbies.

    You could solder the connector directly onto protected cells, which would be cheap-and-easy too. I'm not sure if the protected cells' internal protection is as good as the PCM boards.

    I'm interested to see if those Sony cells test out at 3000mah, or if it's yet another goofy claim. Are they protected?

  68. #68
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    Sure it makes sense for newbies, I was talking for myself though.
    I do not solder on the batteries, I use the spot welding metal thing with the cables soldered on it before I tightly attach it on the batteries with some reinforced tape. I don't spot weld it either, just the tape and some tiny elastic pads to add tension to the connection, add heat shrink and it works fine!
    If very high currents/cell are needed I add some contact silver staff on the contacts.
    Shipping is free from this supplier and for 25$ I can get 6x3000 mAh= 18 Ah of Sony quality!!
    Last edited by manokaiser; 07-11-2011 at 04:21 AM.

  69. #69
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    Quote Originally Posted by manokaiser View Post
    Sure it makes sense for newbies, I was talking for myself though.
    I do not solder on the batteries, I use the spot welding metal thing with the cables soldered on it before I tightly attach it on the batteries with some reinforced tape. I don't spot weld it either, just the tape and some tiny elastic pads to add tension to the connection, add heat shrink and it works fine!
    If very high currents/cell are needed I add some contact silver staff on the contacts.
    Shipping is free from this supplier and for 25$ I can get 6x3000 mAh= 18 Ah of Sony quality!!
    What's "the spot-welding metal thing"- some sort of contact with a wire attached, taped in place?
    What do you do for battery protection?
    What connectors?

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    Sigh. Something that looks a lot like those KD Sony 18650s shows up here: link as "fake sony" with miserable performance. I'm not saying for sure that these are the same, but I'm personally cautious enough with these things to want to stick with my (bloody expensive) AW batteries.

  71. #71
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    What's "the spot-welding metal thing"- some sort of contact with a wire attached, taped in place?
    What do you do for battery protection?
    What connectors?
    It's a nickel metal strip used for spot welding, only I don't weld it on the bats.
    I use Single Cell Voltage parallel for Capacity, no PCB. Overcharge is taken care by the charger, over-discharge by the driver.
    For connectors:
    Polymax 3.5mm, EC3, XT60 and few others from HobbyKing

    Sigh. Something that looks a lot like those KD Sony 18650s shows up here: link as "fake sony" with miserable performance. I'm not saying for sure that these are the same, but I'm personally cautious enough with these things to want to stick with my (bloody expensive) AW batteries
    .

    Now That's a good point!
    I haven't tried these yet so any feedback is much appreciated!
    These though don't mention anything about protection (I prefer unprotected).
    I have no idea if these are original or not but googling I found sites where original Sony batteries are mentioned and sold.
    I guess the only way is to buy and test... or maybe someone has done that already to enlighten us?
    Last edited by manokaiser; 07-11-2011 at 05:23 AM.

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    Frankly I'd be amazed if those "sony" cells were anything but a POS. It is no big deal to order up the shinkwrap material and make any kind or capacity of 18650.

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    ditto ^. Besides, I thought the only 18650 cells hitting 2900mAh had to be charged to 4.35V? Based on various tests on CPF, none of the high capacity cells from DX or KD ever hit more than ~2500mAh, no matter what figure is on the shrink wrap.

  74. #74
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    Quote Originally Posted by Erich von Speedcliff View Post
    Can anyone tell me why LiPo battery packs aren't being more prevalently used? They seem to work very well for RC vehicles....why don't more folks use them for bike light battery packs? I know they need to be carefully balanced when charged, but again, the RC world seems to have embraced them. Why haven't we?
    I think the reason is that most LiPo packs are soft shell and so aren't very suitable for the rigours of mtbing. The last thing you'd want when you fall off is to puncture your LiPo, have it short and then go up in flames. However, you can now buy hard shell LiPos which some people on here use successfully. As long as you pair it with a driver with overdischarge protection you should be fine.

  75. #75
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    Quote Originally Posted by mattthemuppet View Post
    ditto ^. Besides, I thought the only 18650 cells hitting 2900mAh had to be charged to 4.35V? Based on various tests on CPF, none of the high capacity cells from DX or KD ever hit more than ~2500mAh, no matter what figure is on the shrink wrap.
    Some 2900mah cells require higher charge voltages to achieve that capacity. Panasonic makes 2900mah cells that reach that capacity using standard charge and discharge voltages.

  76. #76
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    Like I said, I'll be testing the "Sanyo" battery packs from the eBay vendor, and I'll report back on capacity.

    Hey, brings me to a question- These are 3.7v 5000maH packs- at what discharge rate should I test these with my Turnigy charger?

  77. #77
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    Quote Originally Posted by mattthemuppet View Post
    I think the reason is that most LiPo packs are soft shell and so aren't very suitable for the rigours of mtbing. The last thing you'd want when you fall off is to puncture your LiPo, have it short and then go up in flames. However, you can now buy hard shell LiPos which some people on here use successfully. As long as you pair it with a driver with overdischarge protection you should be fine.
    That's one reason. Another reason is RC style lipo's are optimized for very high currents. Whereas 18650 style li-ions are optimized for capacity. Bike lights do not use high currents and most folks care about runtime vs the size and weight of the battery, so li-ion cells tend to be a better fit.

    There are version of lipo batteries starting to be used in laptops that are optimized for capacity. Apple uses them in all the new MacBooks. But don't expect to see these batteries for sale on the web sites that sell RC batteries.

  78. #78
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    LiPo?

    Quote Originally Posted by MtbMacgyver View Post
    That's one reason. Another reason is RC style lipo's are optimized for very high currents. Whereas 18650 style li-ions are optimized for capacity. Bike lights do not use high currents and most folks care about runtime vs the size and weight of the battery, so li-ion cells tend to be a better fit.

    There are version of lipo batteries starting to be used in laptops that are optimized for capacity. Apple uses them in all the new MacBooks. But don't expect to see these batteries for sale on the web sites that sell RC batteries.
    Thanks for the knowledge guys...I'm not that concerned about size and weight, so I think a LiPo will work just fine for me!

  79. #79
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    Reminds me of a great Simpsons moment: (Scenes from the Class Struggle in Springfield, season 7, before it all went pants)

    Homer: Look at these low, low prices on famous brand-name electronics!
    Bart: Don't be a sap, Dad. These are just crappy knock-offs!
    Homer: Pfft! I know a genuine Panaphonics when I see one. And look, there's Magnetbox and Sorny.

  80. #80
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    Quote Originally Posted by Erich von Speedcliff View Post
    Can anyone tell me why LiPo battery packs aren't being more prevalently used? They seem to work very well for RC vehicles....why don't more folks use them for bike light battery packs? I know they need to be carefully balanced when charged, but again, the RC world seems to have embraced them. Why haven't we?
    This sort of puts me off. http://www.rcgroups.com/forums/showthread.php?t=209187

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    Quote Originally Posted by yetibetty View Post
    I am confused - I thought what was being discussed here was lithium polymer v lithium ion.

    There is nothing I have seen that suggests that Li-poly is any more or less dangerous than li-ion.

    As far as I am aware the differences are that rc-packs usually don't have a hard case and that the high discharge rates mean that they don't have a pcb for protection from overcharge or overdischarge.

    As for weight, there is very little in it

    4 x Trustfire "2400" mah 2s2p gives 7.4V "4800" mah and just under 200 g
    1 x Turnigy 5000mAh 2S 20C Lipo Pack is 280 g

    I haven't measured the true capacity of either the trustfires nor the turnigy lipo pack.

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    Hey guys I have another question about the batteries. If you have a driver with voltage cutoff on at 6v for a 7.4v batt and you balance charge. Is there a need to have a PCM for protection.

  83. #83
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    Quote Originally Posted by Ofroad'bent View Post
    Did Batteryspace charge the extra hazardous shipping fee for these?
    Which PCB did you use for protection?
    Quote Originally Posted by savagemann View Post
    Nope, they are UN Approved NDGR. I think that stands for Non Dangerous Ground.
    I'm not using a protection board. I guess you could say I am "winging it".
    Savageman, I think you were lucky. The below has been copied from this page which is linked from the "warning" section of this battery pack

    Hazard Materials Shipping Regulation. Due to the Department of Transportation's regulations for shipping Lithium battery, there is an additional hazard material handling cost that UPS and FedEx charge "per box" that is NOT included as part of the shipping cost.


    Domestic Ground
    $25.00/BOX
    Domestic Next day/2nd Day/3rd Day
    $35.00/BOX
    Canada / International
    $45.00/BOX




    To make sure your packages can be shipped without delay, please also add this into the shopping cart accordingly for Li-ion/ Polymer/LiFePO4/LiMnNi battery.
    Ground HAZ MAT UN Approved cell/battery*/Prototypes/non UN 38.3 test batteries
    Air HAZ MAT UN Approved cell/battery* only
    Canada HAZ MAT UN Approved cell/battery* only
    International HAZ MAT UN Approved cell/battery* only


    *If we didn't indicate the cell / battery is UN approved in the product's title line, then it is not UN tested yet, please choose UPS Ground. All Haz Mat shippment might be delayed due to shipping carriers check points. Delivery time can not be guaranteed on all shipping method.

    This fee is for one package only, if there is more than one package needed, we will contact you.
    For more information, please also refer to

    http://www.nexergy.com/lithium-shipping.htm
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  84. #84
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    Quote Originally Posted by mercman View Post
    Hey guys I have another question about the batteries. If you have a driver with voltage cutoff on at 6v for a 7.4v batt and you balance charge. Is there a need to have a PCM for protection.
    Yes, if you want to follow the recommended safety procedures. During the discharge, if one of the cells has gone bad it can drop way below the per cell limit and the setup you describe will not catch that. The bad cell could be down to say 2.4V and the good cell could be 3.7V and your driver would be happy since the total is above 6V. Then on the next recharge, that cell could go into thermal runaway. Balance charging will not prevent that.

    It will work of course 99+ % of the time, but sooner or later as the pack get old cells are going to start to go bad. That's when you'll potentially have a problem. So you have to decide if that is worth the few extra dollars for a proper protection PCB.

  85. #85
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    OK then SONY are fake, thanx for pointing out.
    Seems there are some truly nice cells out there at a considerable cost .
    And then there is this option if you go for a 100 pieces
    SO the question is: Can we arrange a Group Buy and share these cells at a most reasonable price?
    How could that be arranged? Anyone done it before?

  86. #86
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    I'm going for these cells as I prefer DIY all the way!
    I am arranging a smaller 20pcs quantity to test out, offered with tabs at a very reasonable price. It seems that these Panasonic NCR18650A 3100mAh are also safer batteries than LiPos and LiCos and cycle longer too.
    If anyone is interested in them drop me a message, I could spare some of them when it comes.
    Attached Thumbnails Attached Thumbnails Batteries, again-ncr18650-3.1-tab.jpg  

    Last edited by manokaiser; 07-15-2011 at 08:38 AM.

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