0
\$\begingroup\$

I have a solar charge controller which can charge 12volts batteries. I have two 12 volt batteries which are connected in parallel. I need to have 24volts output without using dc-dc step up converters. Can I connect two 12 volt batteries in both parallel and series? like first having a parallel then having a series connection with some Diodes to control the current/voltage flow. Is it possible? are there some best practices?

EDIT: goal is do charge/discharge the batteries simultaneously.

\$\endgroup\$
  • \$\begingroup\$ "like first having a parallel then having a series connection" could you clarify this? Is there a switch or control circuit that will select one of the operating modes: charging or discharging? \$\endgroup\$ – vangelo Jul 11 '19 at 20:05
  • 1
    \$\begingroup\$ There's no easy way around this. Either you wire them in parallel and use a DC-DC converter to generate the 24V, or in series and use a converter to charge the second battery, or have a changeover switch or relay that would prevent simultaneous charge and output operation. \$\endgroup\$ – Phil G Jul 11 '19 at 20:09
  • \$\begingroup\$ You can charge in parallel then switch to use in series with what you have. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jul 12 '19 at 1:32
  • \$\begingroup\$ @SunnyskyguyEE75 That's the problem, I need to charge and discharge simultaneously. \$\endgroup\$ – Ata Mohammadi Jul 12 '19 at 8:49
  • 1
    \$\begingroup\$ Then you clearly have proposed an unworkable solution. No PV specs for Voc, P,max, no MTTP controller, no 2V4 charger, no battery balancer and no educated research on these requirements. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Jul 12 '19 at 11:57
0
\$\begingroup\$

On the face of it, not really unless you use switches to take the batteries offline while you charge them.

Now if you can use 2 chargers, and the chargers have a floating (ungrounded) output, you could connect each one across each battery. If the batteries are to be kept online ensure that the charger has current limiting and reverse-current blocking.

Or, use 1 charger and use a DPDT relay to switch the charger between each of the batteries in turn. But then you have to control the relay...

Or, eBay your 12V unit and get a dual voltage unit like this one: https://www.altestore.com/store/charge-controllers/solar-charge-controllers/pwm-solar-charge-controllers/xantrex-solar-charge-controllers-pwm/xantrex-c35-charge-controller-35a-12-or-24v-solar-charge-controller-p2069/

|improve this answer|||||
\$\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.