In considering a DIY UPS-ish system (small bank of AGM batteries and an inverter), I knew I wanted/needed a charge controller, but most I found were just intended for keeping e.g. car batteries topped off.

It has since occurred to me that "solar" charge controllers, of which small 10-30 amp versions are in abundance, run off DC input anyway.

Is there anything wrong with feeding any typical charge controller intended for solar panel input with mains power via an ordinary DC power supply like you'd find on, say, any amateur radio operator's desk? Any special considerations beyond making sure I don't feed the controller more voltage than it can handle?


1 Answer 1


That sounds like a good idea if you can't find a "proper charger" - which certainly do exist.

Some of the solar chargers are very good, with equalisation cycles and more.

I can't immediately think of any disadvantage of doing this. 12V solar chargers are designed to take Vin of at least 18V and probably 20V+. If you get one with "proper: MPPT it will probably allow you to get maximum charge out of a given voltage source. I say 'proper" MPPT as some of the new controllers use quasi MPPT where they load the source to a specified percentage of source Voc, based on typical PV panel load curves. This may well not be the true MPPT point for a semi random power source and worst case may cause loading issues - but probably not.

Large range of typical solar regulators - Australia

MPPT controller with discussion - USA, CA.

BP GCR series learning controllers - may be too smart in this role?

Lead acid charging tutorial bulk, absorption and float ...

  • \$\begingroup\$ MPPT = Maximum power point tracking (Wikipedia) \$\endgroup\$ Sep 23, 2011 at 16:54
  • \$\begingroup\$ Thanks, Russell! I did eventually find a few "large" battery chargers that feed off AC (some at rather ridiculous prices). Since I'm apparently not losing much, though, and since A) being able to hang a couple solar panels off it in the future would be nice, and B) I'm going to have a nice power supply in the near future anyway, I think I will indeed find a good solar charge controller. :) \$\endgroup\$ Sep 23, 2011 at 22:22
  • \$\begingroup\$ Link in the middle ("And a few more") is not working. \$\endgroup\$
    – Kamil
    May 31, 2014 at 23:02
  • \$\begingroup\$ @Kamil - link dead. Removed. \$\endgroup\$
    – Russell McMahon
    Jun 1, 2014 at 6:04
  • 1
    \$\begingroup\$ @Dagelf As in most things, proper design is needed. Behaviour of controllers vary, but essentially all MPPT controllers would provide a continuous regulated output. Switching occurs in the supply but is smoother internally as part of the design. Very cheap controllers may indeed behave as you say. \$\endgroup\$
    – Russell McMahon
    Apr 4, 2018 at 2:36

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