KRSreefer

Hello Lipo experts,

Just wondering if you can run two different lipos in parallel? For example: 3 cell 1475mah 25cwith a 3 cell 1300mah 20c. Or do the lipos have to have the same specs in order to run them in parallel?

Thanks!

guver

My Feedback: (325)

Hi, welcome to RCU. 2 different3 celllipos can be run in parallel.

KRSreefer

Thanks Guver,

Would you happen to know what happens to the C number when two 3 cell batteries are ran in parallel?

-C

guver

My Feedback: (325)

Thecombined pack uses the smallest "C" number of all the parallel packs (or less)

In your case the number might be 18 C , and if the packs vary a lot then the number may even be less than the lowest "C"

rcairflr

My Feedback: (44)

I believe you are wrong on this. The internal resistance of the two batteries will be lower in parallel, so the C rating will be additive of the two batteries. So if you have a 10C and a 15C battery the C rating will be 25 when in parallel. If you add them in series, then the internal resistance would be higher, so the C rating would be lower,

ggcrandall1

The C rate of a battery does not change regardless of series/parallel connection. The C rate will always be the lowest of the batteries being ued.

While you can use batteries of different current rating is is not a good idea. When paralleling batteries they must have the same cell count. They should be the same mah, C, and state of discharge.

Do not confuse C rate with possible current flow. The C rate is the theoretical maximum safe current the battery can provide. However that is not the maximum the battery can provide.

For instance a 3s 2200mah 10C battery can safely provide 22 amps. However the battery could still be loaded to provide many times that much. Of course the attery will be damaged or even destroied if that was done.

So if you have a 3s 2200mah 10c battery and a 3s 2200mah 30c battery in parallel and your motor/prop combination is pulling 44 amps each battery will be drawing 22 amps. Yes they might vary slightly due to the internal resistance of each battery but it will be negligable. So the 10c battery will be providing it's safe maximum and the 30c battery will loafing.

Glen

Rodney

The C rating determines the maximum safe current you can draw from a battery. If you have two batteries of equal voltage in parallel with at least a capacity of 1000 ma, you can draw the current from each battery equal to the C rating of the lowest one; i.e. if one was a C rating of 20 and the other a C rating of 30, you could draw 40 amperes safely. That would be drawing 20 amperes from battery or 40 amperes total. Just a simple math problem.

richrd

I concur for the most part. Parallel adds BUT ! in this real world math an facts don’t work that way. To many if’s… new verse old packs, packs from different manufactures, etc, etc. Unless the manufacturer matched the packs then all is gone in the adds in parallel math BS.
THE ONLY SAFE STATEMENT IS TO USE THE LOWEST RATEING PACK.
This way if the good pack did not get a good charge then the weak pack cannot get destroyed or if the good pack get to be the weak pack then both are going to be destroyed. Get my point this is the real word not school math, the IR resistance is going to change every cycle.
Rich

Rodney