I See Electromagnetic Fields!
All good advice for sure. Thanks.
Before I start spending cash that I haven't really got on new equipment I'd like to learn why the new controller isn't recognizing the new panel's output that I already have here though? So if anyone has any ideas, please fire away...
Cheers, as ever
A PWM controller just shorts panel to battery, then when voltage rises too high it disconnects. While battery is low, PV panel just remains connected and delivers current. Once charged, it toggles between connected & disconnected to regulate voltage.
With a panel disconnected from everything, it's voltage should read 18V to 22V. If it reads lower than battery voltage, it won't do anything to charge.
The charge controller will have a maximum PV input voltage rating. Maybe 25V, maybe 40V. Make sure PV panel isn't higher than that. So long as PV panel is between battery voltage and maximum charge controller input rating, connect it. PV panel voltage should drop to battery voltage. Battery voltage should be pulled up a bit, and will slowly climb to fully charged.