On my boat I have a battrey amg 225ah that is charging with victron mppt I’m going to add another battrey but they are going to be far from each other and I found on internet the this DC-DC charger can someone explain me how to connect them please. The battries are for services not for starting and charging from solar panel.
thank you
Are your batteries providing power to different loads / services and otherwise not connected to each other.
Wiring diagrams for the DC to DC chargers are in the manuals on the product page. Scroll down or use the downloads button.
One of the battrey is for toilet, shower and fridge and the other battrey is going to have a small freezer only
OK, if they are independent systems then it is fine to use a DC to DC charger to charge the second battery from the first battery with the solar and other chargers on the first battery. I suggest placing the DC to DC closer to the second battery as it will boost the voltage loss due to long cables and charge the second battery properly. You can either have a non-isolated version where the two batteries have their negative terminals connected in common or an isolated version where they are electrically separate. Normally a non-isolated is OK in most systems, is cheaper and more efficient. You have to make sure the voltage drop on the cables between the batteries is low to get the best performance. Choose a DC to DC that is large enough to cover the freezer demand and smaller than the MPPT rating to keep some spare output from the MPPT to keep the first battery charged.
thank you very much