Following my previous post Help, Can I Do This. I have done further research.
I wish to put some solar panels on my caravan roof to enable me to enjoy more off-grid locations. I am also going to a couple of festivals in the next few months and require to be off grid for 7 days at a time.
I have decided to install 2 140W solar panels initially (with an option to add third panel later if required or wish to run a small inverter. I intend to spec the system to allow the possibility of adding that 3rd panel later. All panels to be wired in series to allow good voltage and thus some charging when its overcast.
The current battery is a 100Ah EFB battery but I have another identical battery which I can install for off grid use. The plan is to change to lithium at a later stage.
I have looked at the MPPT calculator which for the two panels have suggested a 75/15 and the 100/15 but these are 140% oversized with the two panels, so won't allow the 3rd panel later. The 100/20 is 79% undersizes with two panels but 145% oversized when I add the 3rd panel to the string.
The 100/30 is 64% undersized with the two panels but rises to 97% undersized when the 3rd panel is added.
I prefer not to overload the controller and hopefully if not oversized would run nicely. My supplier has suggested the 100/30.
So my question is. Is it ok to run the two panels on the 100/30 with it 64% undersizes. I assume this will not damage the battery or the MPPT.
The system already has an BMV712 installed in the system, would any further Victron equipment need to be added to the system (excluding isolators, circuit breakers etc).
Thanks for taking the time to read and hopefully respond to my questions
