Just starting to design a 12v/120v system for a travel trailer with PV, LiFePo4 batteries and 30Amp shore power connection. I’d like to use a Multiplus 12/120/3k as well as a SmartSolar MPPT 150/70. When hooked to shore power, will the Multiplus charger and the SmartSolar charger conflict/confuse each other if NOT networked together in some way?
I would guess without a GX network, they would not know when to change charging modes because they are sensing the increased voltage from each other rather than the true battery voltage? Is there another way for the 2 chargers to get in sync without need for a Cerbo GX or similar device?
Attached is a preliminary attempt at a complete system design, which will hopefully answer any questions about my intended application.
They will work together fine, there is no need yo detect the “true” battery voltage. The charger increases the voltage to say 14.4V for absorption and trims current to keep this. More chargers means they will all trim the current, bit one may provide more of the current due to small voltage differences in cables. What I did on my boat in this case was set the Multiplus absorption and float voltages 0.1V lower than the solar so the solar always took priority over shore power as that is free. If there is not enough solar to hold the voltage then the shore power will make up.
Looking at your drawing, if you purchased a Cerbo GX and Touch 50 you would get the advantages of that device and you would not need the Smart Dongle, the Digital Multi Control and you could swap the BMV712 for a cheaper SmartShunt. The savings from not having those would go someway towards offsetting the cost of the Cerbo GX.
@tks25 As a follow up after thinking further, the GX device only synchronises chargers if the battery communicates the charging requirements to the GX device. If you have standalone batteries without communication then the chargers will run independently even with a GX device.
@tks25 one thing to add to @pwfarnell list of good reasons to go with the Cerbo-GX is that if you add a cheap SIM card enabled 4G wifi router to your system, not only can you connect to it via Bluetooth but you’ll be able to connect from anywhere in the world.
My system is very similar to yours in that I’ve got an American RV which uses 12vac equipment thus I use the same inverter. My RV is in the UK but I configure everything from my Turkish Holiday home. Pool, G&T and access to VRM. What more can one ask for.
