I have an UPS with two 6V batteries connected in series. Is it possible to use the same system (UPS) to charge another two pieces of 6 volts battery if all the batteries are connected in parallel to maintain a 12 volts circuit?

Will this affect the charging system of the ups if the connection is made?

  • 2
    $\begingroup$ Doesn't this question belong to Electrical Engineering? $\endgroup$ – Mo_ Jul 2 '13 at 9:08
  • $\begingroup$ Wait, how does connecting all batteries in parallel give you 12 V anywhere? $\endgroup$ – Martin J.H. Jul 2 '13 at 9:39

Yes, if you connect a charged and an uncharged battery in parallel then the charged battery will charge the uncharged one (and of course partially discharge itself). Assuming you're talking about the lead acid batteries usually used in UPSes the voltage of a 12v battery changes by about half a volt between fully charged and 50% charged, so the charged battery will drive a current through the uncharged one and charge it.

I would be cautious though, because lead-acid batteries have a low internal resistance. If the uncharged battery is fully discharged, and the voltage difference is high, you could get a very high current flowing.


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.