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Lipo in Series - must they be the same

Old 07-10-2006, 03:51 PM
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lennyshotgun
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Default Lipo in Series - must they be the same

Do Lipos need to be the same brand or same amp's to run them in series? How bout running 2 paral.
Lenny
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Old 07-10-2006, 04:50 PM
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Crash Test Dummy
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I have always been told that is you are gong to run 2 packs they should be the same Mah and brand battery. I'm no expert but it sounds like it makes sense.

CTD
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Old 07-10-2006, 05:10 PM
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bert269
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I have been using lipos now for a couple of flights. They are the same amps, but not the same brand. After the charge, the charger indicates that exaclty the same amount of amps was put back into both packs.

I would think that it will be the best to have them the same brand and the same current, but at least, definitely, the same current (amps).
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Old 07-12-2006, 02:54 PM
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jperch
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In theory, you could run two packs of different capacities in series. But you would want to limit the amount you take out of the combined pack to the smaller of the two. The same is true for paralleling.

However, given the potential risk, I would not recommend doing this. You should at least have the same capacity packs wired in parallel or series.

Ideally, any cells wired into a pack should be balanced. This means that they should be of the same capacity and state of charge at all times. When you connect two packs in series or parallel, you are essentially creating a larger pack, even if it is temporary. So, while it is possible to get to smaller packs from different manufacturers to be balanced, I would prefer to stick with connecting only packs of the same brand together into larger packs.

That is my $0.02.

Joe
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Old 07-12-2006, 09:15 PM
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slipstick
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Originally Posted by lennyshotgun View Post
Do Lipos need to be the same brand or same amp's to run them in series? How bout running 2 paral.
Lenny
In series it would be really silly to use different capacity cells. Imagine connecting a 1000mAh cell and a 3000mAh cell in series. Since exactly the same current is running through both, the smaller one would be exhausted and it's voltage getting dangerously low while the larger one was still 2/3rds full. A very bad idea . Brand doesn't really have much to do with it but cells should have the same specification, both capacity and C-rating.

In parallel you can use different capacity packs if you know exactly what you're doing because the two tend to balance out rather more. But it's rarely worth the trouble. Again brand doesn't really affect anything but capacity and C-rating do.

Steve
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Old 01-19-2008, 06:02 PM
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stranexuk
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Can you confirm that packs of the same capacity, same manufacturer BUT different voltages can be connected ok in series? ie. a 3S1P3100mAH and a 2S1P3100mAH?
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Old 01-19-2008, 07:57 PM
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Yes that can be done. After all how would anybody be able to make a 5S setup if not?

I do this all the time. I bought some very nice 2S packs on special sale from VampowerPro and made 4S packs out of them by simply putting them in series.
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Old 01-20-2008, 07:04 AM
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DarZeelon
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Brand-names are not everything...

There are few OEM manufacturers that make Li-Po cells for several pack assembly companies, who then supply them to outlets that badge them.

In fact, many eventual outlets may actually be using the exact same cells, that you can use to safely connect in series.

Parallel connection of packs is the one, leading 'violation', battery suppliers use to void warranty claims...
...So I would refrain from using this method and prefer using larger 1P packs, if I ever need more capacity.

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