Solar Panels Query

[Nix]

Ok, as I see it, you're getting a series array of 24v solar panels to make up a 3kW system. As we said before, grid tie inverters automatically isolate from the grid when it goes down and you will get nothing from it, it's part of being G83 compliant. I would personally have an isolator to isolate the panels to the inverter and another one between the inverter and the grid for any work to be done on any part of the system. Please note that 400v DC is a dangerous voltage and not to be tampered with.

So, what to do?

Straight off the bat, you may have a problem with that sort of voltage. Most controllers dealing with 400v will be very expensive. The small ones start at 12/24v then they go up to handling 48v, then 100v, and so on. When you're talking 400v, you're talking high end. You also need to "tap off" or divert that incoming pv with either a two way switch or adaptor. The installers won't help you here cos it will modify their installation and they will be liable for it. Any warranty would be void as well. If you only are charging a couple of batteries, that could be another problem as you're cracking a nut with a sledge hammer! If it's a long haul SHTF scenario then I don't think anyone's going to smack your bottom for accessing the panels for survival but you've got to be aware and competent with the sort of voltages this system is giving out and, no disrespect, but it doesn't sound like you are. You don't want to be found burnt to a crisp!

A temporary measure would be to set up a suitable battery charger to a battery bank. But that's relying on the mains coming back on to replenish the batteries. Not good for a scenario where you need sustained backup over a long period of time.

Difficult this, I know what I would do but for someone like yourself I need to have a ponder...