why this dark activated circuit doesn't work

Thread Starter


Joined May 5, 2016
So to explain diagram solar panel charges battery through controller. From controller load goes to light strip through relay. Relay(12v) is operated by solar panel (15-16 volts), it is SPDT relay and when it is on it does nothing, but when it will go off when it will be dark and solar cell will not provide enough voltage it will connect positive from load to positive to light strip.
Problem is that relay is not going off.
Can you help?


Joined Sep 9, 2010
Your solar controller should probably be in control of that relay, not the solar panel itself. Did your controlled come with documentation? I don't think you've hooked it up quite right.


Joined Aug 7, 2008
In the shade & relay erroneously energized, disconnect the battery & see if relay drops out. If so battery is backfeeding thru controller