Added a winter/cloud cover boost to my solar array

Author	Message
Godoh Guru Joined: 26/09/2020 Location: Australia Posts: 704	Posted: 10:35pm 21 Jun 2025       Hi Gizmo, looks good. I am wondering why you don't use old GTI inverters and backfeed to charge the batteries. GTI inverters are really cheap second hand. I have two that are connected to two banks of panels. I pay less than $100 for a 5 kw inverter. Much cheaper than MPPT controllers. As far as putting more charge into the batteries than they can take, my experience is that the internal resistance of the batteries tends to limit the current. I have around 10kw of panels, but never see more than 2kw going into the batteries. I have my panels arranged with 4kw of panels facing North, and around 6Kw of panels facing NW. So the mornings the North panels that are on MPPT controllers bring the batteries up and in the afternoons the panels connected to the GTI inverters do most of the work. For the GTI inverters I use voltage sensitive relays to switch them out if the batteries are charged up. So far it works great. The GTI inverters are mainly used to charge the car and run bigger power tools. I do have problems on some very dark cloudy days, but fortunately we don't have too many of them in a row. Pete