I just wired a solar panel with solar charge controller (SCC) and battery.

The photovoltaic (PV) voltage displayed on the SCC is 13V, even though the PV voltage without load that I measured with a voltmeter is 19V.

After that I tried to put two PV panels in series and I measured again and got 39V.

But after I installed SCC with battery and connected the PV panels, the SCC still shows the PV voltage at 13V. I measured with a voltmeter and got the same 13V.

Is there a problem with my SCC or my PV panels?


closed as unclear what you're asking by RoyC, Voltage Spike, Nick Alexeev May 18 at 20:23

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ Please provide a diagram of how you have things connected and where you measured which voltages. \$\endgroup\$ – Solar Mike May 18 at 10:47
  • \$\begingroup\$ PV to solar cell port on scc and battery to battery port on scc. I parallel voltmeter at solar cell port on scc. \$\endgroup\$ – Retro Blank May 18 at 12:50
  • \$\begingroup\$ That's how a solar charge controller works. Look at the PV panels as power sources rather than voltage. If you use two in series you need a 24 V controller. \$\endgroup\$ – Misunderstood May 18 at 22:06

The Solar panel voltage is being held to 13V because it is supplying current to the battery to charge it.

That is expected behavior, and not at all harmful to the panel.

As the battery reaches full charge the load on the panel will reduce and its voltage will rise.

Some designs of solar charge controllers will control the power by diverting the panel power into either a resistor or a short circuit in which case the panel voltage may reduce or even cyclically pulse to zero.


Not the answer you're looking for? Browse other questions tagged or ask your own question.