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I have LiPo battery that is in 2S2P configuration, however I need higher voltage (4S) battery for my project. From my understanding 2S2P battery has 4 cells same as 4S (2 in series and 2 in parallel). Would I be able to rewire cells like shown in the image below to achieve this assuming all the cells are the same voltage?

4S configuration

If I understand correctly this would halve the capacity and double the voltage. Would this cause any side effects or potentially damage the battery?

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  • $\begingroup$ What individual cell voltages do you see ? When full or empty? $\endgroup$
    – Tony Stewart EE75
    Commented Jul 29, 2022 at 17:30
  • $\begingroup$ Why do you need 4S? Twice the RPM and half the run time? $\endgroup$
    – Tony Stewart EE75
    Commented Aug 7, 2022 at 2:17
  • $\begingroup$ @TonyStewartSunnyskyguyEE75 For sumo robots run time is usually very short, however every RPM counts. To avoid the extra work and trouble, I opted to instead just buy 4S battery since they are not that expensive. $\endgroup$
    – KlemenPl
    Commented Aug 7, 2022 at 19:09

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Yes, that's exactly right. It's just a difference in how the cells are connected.

Don't worry about balancing the voltage - your charger will do that for you when you charge it. No current will flow between the cells when you connect them.

The biggest issue here is securing the wires so that the delicate cell tabs aren't pulled or moved during use. Look at how everything is insulated and secured, and try to do as good a job when reassembling it.

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  • $\begingroup$ How did you think his charger can balance it if they are not matched? $\endgroup$
    – Tony Stewart EE75
    Commented Jul 27, 2022 at 12:55
  • $\begingroup$ @TonyStewartSunnyskyguyEE75 - these cells have come from a 2s2p battery, they will be matched (i.e. the same type, capacity and age). Why do you think they might not be matched? $\endgroup$
    – Robin Bennett
    Commented Jul 27, 2022 at 15:26
  • $\begingroup$ all cells have some imbalance due to manufacturing tolerances and the longer the weaker cell(s) spends over/under-voltage increases the imbalance. $\endgroup$
    – Tony Stewart EE75
    Commented Jul 27, 2022 at 18:08
  • $\begingroup$ @TonyStewartSunnyskyguyEE75 yes, but how does that affect what I said? I'm not saying he'll never need to balance the pack, just that the charger will do it normally, and it doesn't need any special extra checks. If it worked as a 2s2p, it will work just as well as a 4s. $\endgroup$
    – Robin Bennett
    Commented Jul 28, 2022 at 8:02
  • $\begingroup$ there is no feature in a 2 wire charger to keep each cell within 10 mV (before or after).. The user should test , report to confirm $\endgroup$
    – Tony Stewart EE75
    Commented Jul 28, 2022 at 14:49

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