Originally Posted by PaulinOz
"It seems 12v is the best solution for most boats for Solar
." may be the cheapest or possibly the simplest but NOT
the best. 60 + volts is better.
Higher the panel voltage the lower the current
, means less lose in the cabling from panel to controller for a given size cable. There is no such thing as too much power.
With an MPPT
charge controller you can have high DC voltage off the panels
(my two 250 watt panels
will be wired in series for 60v, for under 10 amps through the wires), run that to the MPPT
, and the MPPT will charge a 12v battery
bank(it will auto sense the voltage if it's any good). Have the MPPT very close to the battery
bank so you only need short runs of large cable.
At home with a lot more panels and power, I have 120v going into the controller, and that feeding 48v battery banks, which then feed 48v to a 220v 8kw/24kw pure sine wave inverter
(pretty much everything in the house plugs in to 220v sockets).
Despite being a big fan of 48v in optimum systems (all running off mains voltages), for the boat I will put in a 12v to 110v 2500 watt inverter
, as most things will be running off 12v anyway (only a steam cleaner and dehumidifier will be run at 110v).
Don't forget to put automatic circuit breakers (resettable fuses
which you can manually trip when necessary) in to be able to isolate the panels, charge controller, and the battery bank.
PS Even though you will only have 10 amps max going to the controller, make sure it can handle over 41 amps at 12v to feed the batteries with its output.