connecting lipo in parallel and series, pros and cons.

[rayshaw23]

i have 6 similar lipos, all 2200mah with 20c. now upgrading to bigger wingspan, hoping to reuse my lipos and connect them in either parallel or series.

i know that if i connect 2 of them in parallel, i will be getting 11.1V 4400mah with 20c. which translate to a max discharge of 88A. however will there be any cons?

what about in series, i will get 22.2V 2200mah with 20c. which translate to a max discharge of 44A. is there any mistakes in my calculation? and are there cons?

thank you.

[Schneizel]

There's no problems with your calculations.

The first obvious con I can think of is there be an additiinal bunch of wires which could add to the weight of your models. Not a big problem though

Second would be if your packs are mismatched, one pack may drain more than the other in series connection. This could cause one of the packs to fail earlier in a series connection. It would be a good idea to match your packs by internal resistance and capacity. This is not applicable to parallel connection.

[feudallordcult]

also ensure that the "cycles" of the lipos are similar in number. dun pair a new batt with an old one...sumtin bad might just happen.

[Babylon5]

Hi, parallel lipo , is not so simple in matching, you need to get a current meter preferable the thong type which is easier to use. During discharge make sure each pack discharge about equal amount of current within 95-100% of each other.
eg if total current is 40amps.
Ideally each pack discharge 20amps but one 21amps and 19 amps is still acceptable provided you don't fly until battery is nearly depleted.

Series Lipos matching are more complicated as you need to match the internal resistance of each cells. If not , the weaker pack or cells (higher internal resistance) will be the first to be damage over time and usage due to reversed voltage discharge through itself. That is why well matched 6S lipo is more expensive than the priced 2x 3S lipo of the same capacity.
Each of the 6 cells are matched during manufacturing processed.

cheers

[edmond22]

Ok from my experience.

I gone through several flight packs already on the following:

F5B - 4s2200x2 parallel for 280 amp draw (16x17 square prop)
3D 78 inch plane - 5s5000x2 series for all out 3D 8 min flight
Trex600 - 6s3000x2 series for all out 3D as I can manage
EDF - 4s3000x2 series for 230km/h speed flight

Just fly, charge them individually after session. Check balance manually with probe meter once a month and balance if necessary. I never discharge more than 80%, usually 75ish and land.

So far, no prob and they lasted a long time for me. 3D plane achieved even more than 100 cycle and it is the cheap 20c stuff. I did not pre-measure/ match lipos, just buy the same stuff and marked them as the same badge for use.