Author Topic: Paralleling LiPoly packs  (Read 2481 times)

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Offline cyberfishTopic starter

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Paralleling LiPoly packs
« on: July 27, 2010, 02:22:09 PM »
Just wondering if it's safe to use LiPoly packs in parallel.

Since they have very low internal resistance (few milliohms), doesn't that mean even a small difference in voltage will result in one battery charging the other with dangerous current?

Do I need to add schotkey diodes? It seems like all schotkeys that can take the current I need (~25A) have large forward drop (almost 1V). That will waste a lot of power, assuming I can even cool the diodes.
« Last Edit: July 27, 2010, 02:23:56 PM by cyberfish »
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Offline amando96

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Re: Paralleling LiPoly packs
« Reply #1 on: July 27, 2010, 03:20:55 PM »
I am NOT certain of this, but when a pack is for example 2S 2P, it meansit has two cells in series, and two in parallel, I don't think they have diodes, because the chargers have a balancer.

And again, I'm not sure of this!
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Offline Razor Concepts

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Re: Paralleling LiPoly packs
« Reply #2 on: July 27, 2010, 04:50:15 PM »
It should be fine as long as you use the paralleled packs together always so that the voltages are close. Since the voltages are so close, there won't be any significant current flowing between them. Paralleling is common in RC use so it is fine
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Offline cyberfishTopic starter

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Re: Paralleling LiPoly packs
« Reply #3 on: July 28, 2010, 06:16:02 PM »
Thanks!

I think I'll just go with a bigger pack and save the trouble.

I was going to get 2 smaller packs so I can charge them up twice as fast using 2 cheap chargers... guess it's not worth the trouble.
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