I have a caravan equipped with a solar controller for the roof panels. When parked in the shed, I'd like to keep my lithium batteries charged using a solar panel on the shed's roof. I'm currently considering connecting the shed roof panel to an MPPT controller, and then linking that to the caravan's MPPT controller. Is this setup advisable, or should I connect the solar panel directly to the caravan to bypass the shed controller? Essentially, I'm wondering if I can set it up like this: Shed Roof Panel -> Shed MPPT Controller -> Caravan MPPT Controller -> Caravan Battery. Both controllers are suitable for lithium batteries but are different models.
1 Answer
It's generally not recommended to connect two MPPTs in series like that. You have a couple of options instead. You could add a 12v DC port to the caravan (like an Anderson port), which would allow the shed MPPT to charge the caravan battery directly. Alternatively, if you want to connect the shed panel feed directly, use an Anderson port to connect to the caravan's MPPT input, but only if both systems have the same voltage. Mixing a high voltage system with a lower one could lead to problems, so just keep that in mind!
Thanks for clarifying! I think I'll go with the Anderson connection directly to the battery from the shed MPPT.