I have a solar panel, a battery and a charge controller. I didn't pay for any of it so I thought I would just wire them up and see how it goes.

The battery won't charge. The charge controller has a battery level indicator and it has stayed at middle for over a week. The solar panel doesn't have a high wattage so I wasn't expecting it to charge quickly but I think It would have charged by now. Could somebody tell me if there is anything wrong with the setup?

I believe I need 2x 12V solar panels to give 24V to actually start charging the battery. Is this correct?

All of the parts are definitely working. I also would like to know how long it would take to charge the battery fully with no load. I have worn Google out searching for how to do that but I need it to be put simply and into context. If someone could briefly demonstrate, that would be great. Anyway, the info on the different parts:

Solar Panel

  • 12V
  • 5W


  • 12V
  • 4.5AH

Charge Controller

  • 12/24V (auto)
  • 5A



You do need more than 12 volts to charge a 12 battery. Also how do you know that your solar panel is producing even 12 volts? Just because that is it's rating doesn't mean it always produces that value. Do you have enough sunlight? Have you measured the output of the panel? Can you provide more information on the charge controller? If you did provide 24 volts to the charge controller, how much voltage will it apply to the battery which is important because 24 volts is probably too much. Your panel is rated at 12 volts and 5 watts. Thus, assuming it is getting sufficient sunlight, its maximum current is 0.42 amperes. At that level, charging a 4.5 AH battery, would take a minimum of almost 11 hours.

  • \$\begingroup\$ Thank you sir for your answer. I know for sure now that the solar panel definitely won't charge the battery since it's only 12V and probably isn't actually producing that much anyway. Could you tell me then if adding another 12v 5w solar panel in series would charge the battery (how ever slow it would be)? \$\endgroup\$ – user2329585 Aug 17 '13 at 15:41
  • \$\begingroup\$ Adding anther 12v solar panel in series would probably allow for charging the battery assuming the charge controller is designed for this application. \$\endgroup\$ – Barry Aug 18 '13 at 1:23

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