1
\$\begingroup\$

From various other questions on this site, I have read that running 2 LiPo batteries in parallel is a bad idea, and the best way to fix this is to add diodes in front of them.

I am looking at an application where 2 batteries will be used in parallel and the current draw can be up to 50A. With a 1 volt diode drop (most higher current diodes are higher voltage drops) this would be dissipating 50W of power. This would take a sizable heat sink on the diode.

Are there any other ways to run batteries in parallel? I am looking for extended runtime by placing them in parallel, not more current.

\$\endgroup\$
3
  • 2
    \$\begingroup\$ I think your premise is wrong, paralleling LiPo cells is perfectly fine, you just need to be very careful. If you still want to add some protection you can use fat mosfets, the on resistance can be as low as few tens of mOhms which means some 100ish mW of dissipated power. \$\endgroup\$ Oct 3 '16 at 11:33
  • 1
    \$\begingroup\$ As stated by Vladimir, paralleling LiPo batteries is fine. Paralleling batteries with MOSFETs (i.e. drain-source resistances) is nothing different from paralleling directly, though. \$\endgroup\$ Oct 3 '16 at 11:41
  • 1
    \$\begingroup\$ You could consider putting them in series and using a high power buck regulator - I think you'd probably get 93% efficiency and significantly improve the losses and you'd get voltage regulation (if needed). \$\endgroup\$
    – Andy aka
    Oct 3 '16 at 11:42
1
\$\begingroup\$

Connecting LiPos in parallel is fine. You can even connect thousands of them.

The worst thing I believe could happen is that one of the battery fails and the other rushes a lot of current into it. The best way to protect against this would be to use individual fuses on each battery.

Furthermore, you can replace diodes with FETs, although I'm not completely sure if it works to "isolate" a battery with lower voltage.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.