Richard Mackay

Take the suspect panels down and set them up on the ground. Measure the volts of each panel..

Do you mean a charge controller when you refer to 'PWM'??

Agreed with water heating via solar bring the best option. As far as the cost of water heating of gas vs grid my understanding is they cost the same. But gas cooking has lots going for it. Battery storage for cooking can't compete presently.

Isn't everything on Facebook suspect??

What power (current) are you needing to feed?

Use a laptop PC

Have a look at this discussion:

Phone them..

What are you needing backup power for? Are these devices located in the same area?

I presume you are not feeding into the grid?

The argument I have heard is that the grid is cheaper than using batteries.

What information is available from your inverter? (a list of them provided by the manufacturer would be appreciated!) And how do you read this data (wiring, plugs etc.)

This is my pet subject: the scheduling of RE power. It's not easy to do with intelligent control (i.e by determining the available power and deploying it appropriately) It appears that with inverters that don't have a non essential output it's difficult to determine what the available power is. This puzzles me!

The non essential load supply will switch on when power is available. If you have a lot of PV panels then it can deliver a lot of power. So no need to reduce the size of your element before you see how much power is available. Those without a non essential output reduce their geyser element size so it won't overload the inverter if other loads are also on.