Is it possible to damage a phone battery when charging with a current source?

Situation: I am currently busy with a project where we want to use 200 watt solar panel to charge as many phones as possible. My plan is to find a charge controller to convert the voltage to 5 volt. After which I can connect about 10 USB sockets in parallel. A battery will also be connected to the charge controller to reduce the intermittent behavior of the source.

Because the current generated by the PV module can be quite high. I was wondering if this could damage the phone batteries.


  • \$\begingroup\$ Just to check, you are powering the phones with 5V, not the batteries? Putting 5V directly into the batteries would be bad; the phone has extra charge controllers and regulators. \$\endgroup\$ – SomeoneSomewhereSupportsMonica Jun 23 '16 at 15:18

Is it possible to damage phone battery when charging with a current source?

Yes as it is also possible to damage a battery with a voltage source. But your battery is charged by a charging circuit that behaves as a current source (when the battery is quite empty) and later as a voltage source (when the battery is almost full).

Sure, now you're confused !

Damage occurs when the current or voltage is too high. Simply prevent that and you will be fine.

But actually your headline is not your real question. The charging circuits are in the phones and it should stay that way for safety reasons.

All you need to do is provide 5 V to the phones. This is what planned you to do already.

The fact that the PV module can generate a high current or voltage is irrelevant, it should generate 5 V DC for the USB and that's it. Sure at the solar-panel side of the PV controller the voltage and current will vary but a proper PV controller can handle that. It will simply convert the energy to 5 V or 12 V at the output and the phones will simply take as much current as they need.

If you cannot find a charge controller that can provide 5 V, you can use one that provides 12 V and use DCDC buck converters like this one to efficiently convert that 12 V into the 5 V you need.

  • \$\begingroup\$ Thanks alot! very clear answer and precisely what I was wondering. It is indeed hard to find a 5V charge controller, so thanks for the additional remark. \$\endgroup\$ – Wappie Jun 23 '16 at 14:02
  • \$\begingroup\$ My pleasure :-) Many charge controllers output 12 V so that you can connect it to a 12 V SLA battery so that when there's no sunlight the 12 V goes directly to the output. \$\endgroup\$ – Bimpelrekkie Jun 23 '16 at 14:06

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