question

Hi there Kevin I would suggest using a victron MPPT charger for the battery bank, the correct size can be achieved using Victron’ calculator in the phone app. This would charge your battery bank independent to the multiplus units, depending what input etc for your panels and how many etc. I have the MPPT 150/70tr the first number is max input panel voltage in my case 150v DC. The second number is the charge current max. For your battery bank I would recommend requesting the manufacturer battery settings technical data and thus selecting and setting the mppt from there, the bluetooth helps so much with this and for monitoring also.

All the solar panels are usually dc and the mppt is also dc only then it becomes available as Ac through the inverter output.

I would double check with victron for setting the multiplus disconnect and Re connect assistants just to ensure the system is set correctly and is safe also.

I hope this helped a bit thanks David.

Studying this some more I cannot find an assistant that will do what I want it to do for a DC coupled system. The problem is that the assistants do not know if the AC Input on the multi is grid or generator. That means that the assistant cannot properly know when to prioritize the AC input for faster charging when the generator is running vs prioritizing solar when the grid is connected to the AC input.

In my opinion this leaves me with not saving any money when connected to shore power, if I use a DC coupled system.

If I go with a AC coupled system then most of the problems are solved.

Hi @blskevin

You have several options to switch shore or genny power: https://www.victronenergy.com/media/pg/Automatic_Generator_start-stop/en/which-relay-and-control-to-use-.html

Essentially it's the same function for both, once you have solar and prioritizing it.

You'll find dc-coupled pv far easier to set up correctly, more efficient, and likely cheaper too. Most ac-coupled kit needs higher V panel strings, and on a boat, especially with selective shading, this might be a game-killer.