Maintenance & Restoration

Sparky0 · 08-01-2017, 07:15 PM

I have this charge controller... http://www.hqsolarpower.com/v/vspfil...CTRL-30LCD.pdf

Interesting thing is when I disconnect the panels (switch on the pos wire), I get a reading at the controllers panel terminals of 1.7v

Can anyone explain this? It's showing no amps delivered, as it should, but where is the 1.7 volts coming from? The controller?

Byron Kinnaman · 08-01-2017, 10:44 PM

Quote:

Originally Posted by Sparky0

I have this charge controller... http://www.hqsolarpower.com/v/vspfil...CTRL-30LCD.pdf

Interesting thing is when I disconnect the panels (switch on the pos wire), I get a reading at the controllers panel terminals of 1.7v

Can anyone explain this? It's showing no amps delivered, as it should, but where is the 1.7 volts coming from? The controller?

The voltage is coming from the house battery. If were able to look at where the wire goes into the panel you'd find a diode. Solar panels without diodes will run the battery down at night. A diode in one of the lines (Kirchoff's law indicate it doesn't matter which line as long as it'f point in the right direction) will stop the two way street to and from a solar panel.

Sparky0 · 08-02-2017, 12:35 AM

Yes, I've heard of that. How does the voltage run back to the panel with the positive panel wire disconnected?

Sparky0 · 08-02-2017, 12:44 AM

wait. I get it. the voltage will still show across the controller terminals even if the panel is isolated.

J Ron · 08-03-2017, 03:41 AM

Because a voltage shows does not mean current is flowing.

Sparky0 · 08-03-2017, 07:58 AM

a little disappointing as this controller is supposed to have "night time reverse charge protection"

J Ron · 08-03-2017, 08:27 AM

Most solar panels have built in blocking diodes.

Sparky0 · 08-03-2017, 08:38 AM

Quote:

Originally Posted by J Ron

Most solar panels have built in blocking diodes.

This is true, I think I have a non-issue here. Thanks for all your replies.

Sparky0 · 08-04-2017, 09:30 AM

got a response from the manufacturer.

"The controller does have protection against back feeding, as for the voltage at the panels terminals that is normal there will be surface voltage at the screws but no current. "