IRONMAN1

if i run 2 lipo's in parallel will it double the c rating?

morgoth

No, it will double the mah's. But it will give you a double currect rating.

An example with a 2000mah 40C lipo.

Single lipo: 40C * 2A = 80A
Parallel: 40C * (2A*2) = 160A

8ight-e

iTrader: (58)

Correct the packs actual "c" ratings remain the same, but with the increased capacity going from 2000 to 4000mah (for example) you essentially double what the pack is capable of, obviously voltage remains the same.

40c x 2000mAH = 80amps
40c x 4000mAH = 160amps

Also note you want packs of the same "C" rating, ideally the exact same packs when in parallel. Mixing C ratings you will see the higher rated packs holding voltage longer than the lower rated packs, and this could actually take the lower c rated packs voltage down below the limit. This would then cause early death as the stronger pack will essential give a false total voltage read to the ESC and keeping it from cutting on time.

IRONMAN1

This one is for you people who have re-com-figured a lipo

what do you use/how do you separate the cells on a lipo (remove the double stick tape)?

IRONMAN1

was that question taboo?

If so in sorry

Duster_360

iTrader: (21)

Not taboo, just not many people do it. There's so much lipo paranoia out there, most just discard one when there's a prob of anykind. I've had some that are so poorly put together, it was just a matter of taking the outer shrink off and cutting a band of fiber type tape wrapped around the outside of the cells, there was nothing at all between cells.

Others, its been a major chore. You can't use anything metal thats sharp or you'll puncture the lipo cell and its over at that point. I found a plastic cake cutter that's dull and helps get them apart. A plastic knife also works. You just have to go slowly and let the tape peel as you pry. Some of this tape thats been used is easier to get apart when the lipo is cold. Just be careful, take your time anbd be patient.

8ight-e

iTrader: (58)

Every manufacturer or distributor builds their packs a little different.. there were not many answers because we don't know what was used to adhere them or anything about them. Nobody wants to give you bad info that could cause issues/damage. If they used a sticky pad or glue btw individual cells you have to be SUPER careful pulling apart not to ruin either of the two lipo's outer wrap, you may not even be able to get them apart! I've rebuilt, reconfigured 12-15 packs over the last few years, but I wouldn't recommend it for everyone.

makaluch

iTrader: (36)

Parallel - MAh multiplies by pack count, amp output multiplies, voltage same as single pack.

Series - MAh same as a single pack, amp output same, voltage multiplies by pack count.

Be careful in your thinking. A pack is different than a cell. It can get confusing. Most packs are listed as cells in a series (2S, 3S) but packs are just multiple cells that can be configured in parallel (1P, 2P) as well as in series. Sometimes you'll find mixed configs in a power system.

The applied thinking is:

*if you're running long mains and need more runtime you'll stack your MAh by using two small packs in parallel to keep the weight down. Charge at single pack voltage and you can push double the amps in, although I don't recommend it if you have the time to charge slower. (I think this is the answer to your question).

*if you want a 4S (14.8V) or 6S (22.2V) but you only have 2S(7.4V) or 3S(11.1V) packs you can use a matched pair in series to double the voltage of a single pack. Charge at the doubled voltage and push the same amps that you would in a single pack.

Custom building your lipo packs is not recommended for the average guy. They are fragile. If you cut the bag or crack or crush the brick you have most likely created an internal short. Not all shorts immediately fail the pack (blow up or puff). They create hot spots, imbalances, and falter before they fail...sometimes dramatically and sometimes not.

makaluch

iTrader: (36)

If you're interested in diving down the wormhole here's more stuff to think about:

Charging cells in a series - the first cell gets all of the input and passes it to the next cell. That cell trickles into the next and so on. It's an overflow system. Balancers attempt to regulate this by actively pulling down the first cell and passing it to the other cells faster. It's not a perfect science and heat can complicate the process further (pack or cell lifespans).

Charging cells in parallel - the voltage and amps are spread across all cells and are generally dumped into each cell at the same rate. Balancers have an easier time matching but most balancers only see voltage (one one of three parts of the overall power of the cell) so it's not perfect either.

Mixed systems require smarter balancing. That's why you see complex logic circuits on the balancing adapters. Mixed systems are the least perfect. That's why, personally, I won't charge lipos at max rates when I have time.

Power (watts) = volts x amps
Volts = amps x resistance

Resistance is the major thing that dictates your C rating...the ability to "dump" power fast, or accept power fast. Resistance is also omitted from any discussions or rating systems for simplicity sake. No one thinks about it even though it's the thing that creates heat. When you push/pull more amps (charge or drive) than the pack is peacefully willing to accept/give (resistance) the wasted energy is converted to heat.