Im trying to do a DIY RC car with uses two 12v motors as well as some LEDS servos and Arduino components. I was planning on using two 3.7v 2600MAH 25A 18650 battery cells on parallel to have a bigger capacity while keeping the same voltage. Considering this, would I be able with a boost converter increase the voltage to 12v to power the motors and then charge the batteries with a TP4056? Would there be any problems with trying to do this or should I try something different?

I was also think on maybe trying to use four batteries to double the voltage and capacity (or maybe 6 batteries to have triple voltage and capacity), in this case I should use a 2S or 3S BMS right?

Im pretty new to this and I know very little about batteries so sorry if my logic is wrong. Thanks!

  • 3
    \$\begingroup\$ Use 3 batteries rather than a boost converter, with a proper 3S charger and BMS. \$\endgroup\$
    – user16324
    Commented Feb 9, 2021 at 22:34
  • \$\begingroup\$ If you decide to use 4 batteries (best choice from your propose), connect them in series and use a buck converter, maybe even linear regulator. There is no reason to use a boost. This leads to use 4S BMS. \$\endgroup\$
    – user208862
    Commented Feb 9, 2021 at 22:46

1 Answer 1


tl; dr: consider a 4s RC hobby pack+charger solution. All the problems are solved for you.

I can't recommend 3s + boost converter for running a high-current motor load as this adds losses and increases the current demand on the battery pack, shortening its life. Using 4 cells (4s) is better, and as it so happens this is a popular pack for RC cars anyway. Your 12V motors will do fine with it.

Also, by getting a pre-made 4s RC pack it will have over- and under-charge protection built in. This is important for safety and preserving the battery.

Finally, you have your choice of chargers which can charge your 4s pack up to 14.8V. The intelligent ones can be set to get the best performance and life out of your battery.

  • \$\begingroup\$ In general, get motors to match the batteries, or batteries to match the motors. Converters are big, they cost money, add weight, and no matter how close to 100% efficient they are, they still waste power. \$\endgroup\$
    – TimWescott
    Commented Feb 10, 2021 at 1:49
  • \$\begingroup\$ 3S is nominal 11.1V without a boost, plenty for most (but not all!) 12V motor applications while 4S may be too high voltage for some. Fine if the motors are running from a speed controller, may be too high if simply switching them on/off. \$\endgroup\$
    – user16324
    Commented Feb 10, 2021 at 13:04

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