Stacking batteries in series for multiple cell counts

[The Violator]

I have a question for the more experienced. With all things being equal would stacking different cell counts affect performance. For example.

1. 1 6s battery
2. 2 3s batterys = 1 6s
3. 3 2s batterys = 1 6s
1. 1 2s and 1 3s = 1 5s

I would love to run 6s but was thinking that 2 3s batteries would be more pratical. How about a 3s and 2s to make a 5s.

Size would be a concern, but not as much as being able to use each battery in more applications. This all pertains to my 1/8th scale buggy, but should work for every application.

This assumes the mix and match packs are of the same size, brand, c rating, etc.

I have several 2s packs for my slash. If I bought 2 3s packs and 3 2s packs that would give me a choice to run 6s, 5s, 4s, even 3s and 2s all out of 5 packs. Is there a negative I am missing aside from size.

Thanks
Ted

[jason]

Also if you run parallel a 3s 5000mah 35c with a 3s 5000mah 35c, you end up with a 10000mah 70c.

[Nabil]

if they are the same size, brand, everything but cell count, you shouldn't have problems with any of those configurations

[The Violator]

Originally Posted by jason

Also if you run parallel a 3s 5000mah 35c with a 3s 5000mah 35c, you end up with a 10000mah 70c.

For those extra long sessions, but wouldn't you still keep the same 35c rating. There would be more amperage available, but only because of the extra mah available.

Originally Posted by e-hills4x4

if they are the same size, brand, everything but cell count, you shouldn't have problems with any of those configurations

Thats what I was thinking, but we all know what happens when I start thinking on my own

[bpare207]

Originally Posted by The Violator

For those extra long sessions, but wouldn't you still keep the same 35c rating. There would be more amperage available, but only because of the extra mah available.

You are correct sir

[KC_JoNeS]

And, just so there is no confusion, here is a simple diagram to help explain the connections.



I personally like to make some real simple connectors like this.

Casey

[RebelRacer]

Could you run a 2s and a 3s parallel? or would they have to be the same "s" count?

[KC_JoNeS]

Originally Posted by RebelRacer

Could you run a 2s and a 3s parallel? or would they have to be the same "s" count?

I recommend against doing that. In series, it is ok.

[Charlie-III]

Originally Posted by KC_JoNeS

I recommend against doing that. In series, it is ok.

+1.
In parallel, the 3S would supply most power until it dropped to ~2S levels, then the 2S would also supply power. This would overdrain the 3S since the LVC (in the ESC or external LVC) wouldn't know what is going on.

[dmcchaser]

Originally Posted by Charlie-III

+1.
In parallel, the 3S would supply most power until it dropped to ~2S levels, then the 2S would also supply power. This would overdrain the 3S since the LVC (in the ESC or external LVC) wouldn't know what is going on.

Also, the two batteries of differing voltage would attempt to equalize. Picture two 55gal drums next to each other connected at the bottom with a pipe. The 3s drum is filled with water, and the 2s drum is filled 2/3 up. When the hose is connected (the batteries are connected in parallel) the water levels will equalize.
In the case of the batteries, current will flow from the higher voltage 3s pack into the 2s pack, overcharging it and most likely damaging the lipo pack.

[Jenkins88]

So if you run batteries in parallel it just increases the capacity? and If you run them in a series it doubles the power output?

[92LILREDYJ]

Yes parallel increases cap. I don't think it increases your C rating, BUT it does increase your total amp draw rating for sure. You get the amps a lipo can dish out by mulitplying your C rating X Mah. 5000 20c=100amps if you had two in parallel you would have 10000mah X 20c = 200amp.

Series adds the number of cells together not always doubles... you can run a 3s & 2s=5s. They need to have the same ratings though.(mah, c, brand) You could run a 3s and 1s if you wanted, each cell is its own battery there just wired together in series inside the pack.

[Stregone]

Series adds voltage, parallel adds capacity. Short and sweet version.

[Calderwood]

Originally Posted by jason

Also if you run parallel a 3s 5000mah 35c with a 3s 5000mah 35c, you end up with a 10000mah 35c.

Fixed it for ya.

[dmcchaser]

Actually running a pair of 35c batteries in parallel will give you an increase in the amount of current that can be drawn, since the power drawn is split evenly between the two batteries.


As an example, lets say the RC car is drawing 20 amps.
On a car with a single battery, 100% of that 20 amps is flowing from the one battery.
On a car with two batteries in parallel 50% of that 20 amps flows from each battery.

If the car has 35c 1000mAh batteries, that means 35 amps can be drawn from each battery without damaging it.
(1A*35 = 35A)
If two of these batteries are in parallel, that 35 amps will be 50% of the current available, for a total of 70 amps.

If we consider the two batteries in parallel as one battery pack, it does not give a 70c rating, since the "C" rating is based on the storage capacity of the battery and the amount of current it can produce.
Our new 2000mAh battery is still 35c, because it can produce 70 amps.
In this case one C is 2 amps 2A*35 = 70A

To sum up, double up the batteries, double the amperage you can draw.