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A123 A123 Battery Support


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Old 03-15-2009, 08:53 AM   #1
t2o
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Default Who's balancing? Who's Not?

I have not been balancing my 8s2p packs, in fact, don't even have balancing leads on them. My 3s packs never get out of balance regardless of use or charging technique.

I am considering peeling the shrink off my big packs and checking them for balance but thought I might get some info from you guys before I bother.

Those of you who do balance, how out of balance do your packs get?

Also what do you think about this info as it refers to overcharging as a means of balancing:
http://www.modelelectronicscorp.com/...uct.php?pid=16 ?
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Old 03-15-2009, 05:32 PM   #2
ping
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I'm not, after thousands of combined cycles on probably close to 3 dozen different packs I have for both RC and ones I've made for work.
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Old 03-15-2009, 09:14 PM   #3
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I only do so very rarely, and more out of habit than necessity. It's actually quite difficult to do well with my LiPo oriented equipment. It's quite possible to put the packs out of balance if you're not careful to only balance when the packs are over 3.6v/cell.
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Old 03-18-2009, 12:19 PM   #4
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When I first built my 3s and 7s pack from a dewalt pack I bought off ebay, the cells would go out of balance really bad when charging. But, now that they have some cycles on them, they are staying balanced really well. So much, that I don't think I'm going to put balance leads on the 7s pack. I have them on the 3s, but only because I had a connector laying on the bench.
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Old 03-18-2009, 01:12 PM   #5
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Same here. New packs need some attention for the first few cycles, then they pretty much just do their thing!
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Old 03-18-2009, 01:41 PM   #6
justinone
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I think if you charge them at .5-1C for the first few breaking cycles, they will do fine. I don't balance anymore, too much hassle and slows you down. most balancers can't keep up with the charge rate I pump into the pack, so it's not gonna work for me.

I can be charged up in 5-10 minutes, then the balancer will take another 5-10 minutes maybe more.

actually if you can charge and dischage each cell for about 10 times when new, you can them build a matched pack, and everything shoud allways be equal for the entire packs life.
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Old 03-21-2009, 12:59 AM   #7
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i just got my new charger, the hyperion 0610i duo and was wondering how to cycle my a123 packs? what is the discharge voltage?

thanks,
G
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Old 03-21-2009, 09:18 AM   #8
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Quote:
Originally Posted by neavissa View Post
i just got my new charger, the hyperion 0610i duo and was wondering how to cycle my a123 packs? what is the discharge voltage?

thanks,
G
Don't bother, just go fly. Just balance them before each flight for the first few charges. From my experience, the more you "punnish" A123's the better they behave...
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Old 03-21-2009, 01:34 PM   #9
neavissa
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i hear that a lot...thanks but does anyone have a discharge voltage for me to use when discharging them?!

thanks,
G
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Old 03-21-2009, 01:48 PM   #10
wlfk
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Your heli will not have enough power to stay in the air, before you have come anywhere close to damaging them. I seem to recall 2v/cell as being a 'safe limit' but in practice I've never come lower than 2.7.
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Old 03-21-2009, 01:53 PM   #11
neavissa
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Talking

i should have mentioned two things:
1. i am using them in cars (please don't kill me)
2. i wanted to balance my packs on my new charger and got so excited to do it. when it was asking me what discharge voltage to use, i panicked and started posting...
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Old 03-21-2009, 01:59 PM   #12
t2o
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I googled "a123 storage charge" and the first hit was this
http://www.flyelectric.ukgateway.net/lithium-a123.htm
I like it! LoTs of good info.
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Old 03-21-2009, 02:37 PM   #13
neavissa
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Quote:
Originally Posted by t2o View Post
I googled "a123 storage charge" and the first hit was this
http://www.flyelectric.ukgateway.net/lithium-a123.htm
I like it! LoTs of good info.
thanks!
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Old 03-22-2009, 07:19 PM   #14
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I do not balance anymore. I am using solderless power tubes and take apart my packs about every 30 cycles to check balance. The cells all stay pretty well balanced. I have found , as others have stated, new packs due require balancing. It helps to charge new cells individually.
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Old 03-22-2009, 07:27 PM   #15
neavissa
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Quote:
Originally Posted by pjpg View Post
I do not balance anymore. I am using solderless power tubes and take apart my packs about every 30 cycles to check balance. The cells all stay pretty well balanced. I have found , as others have stated, new packs due require balancing. It helps to charge new cells individually.
where do you get those tubes from?

thanks,
G
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Old 03-22-2009, 10:21 PM   #16
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I get them from modelelectronicscorp.com. After checking the link they have gone out of business. They have a patent on the tubes and I have never seen them for sale anywhere else.
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Old 03-22-2009, 10:24 PM   #17
neavissa
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Quote:
Originally Posted by pjpg View Post
I get them from modelelectronicscorp.com. After checking the link they have gone out of business. They have a patent on the tubes and I have never seen them for sale anywhere else.
too bad, maybe we should make our own. i didn't even know about those tubes till i read your post...

thanks,
G
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Old 03-23-2009, 06:31 AM   #18
wlfk
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What's innovative about putting batteries in a tube? (genuine question - perhaps they have a particularly snazzy design of spring?)
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Old 03-23-2009, 08:25 AM   #19
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My heli the Logo 500 requires end to end stick packs to fit the frame. I do not like the idea of trying to solder end to end and the power tubes allow that configuration without soldering. there are no springs involved. the cells are in direct contact and compressed and held in place with end caps the tubes and threaded rod. For what I needed I just felt they were good solution.
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Old 03-23-2009, 08:47 AM   #20
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I made a pack for my 600 by folding the DeWalt cells over. I didn't have to do much soldering, though presumably it weighs a bit more than it othewise would.

To patent something it has to have a significant innovation. I just don't see much that's innovative about that arrangement, though perhaps I'm setting my barrier too high.
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