Where to connect MPPT input?

[jefndeb]

Hello,

I am in the planning stage of a solar panel installation on our Maniship 40.

I think I will install one LG 375 watt panel with a Victron MPPT controller.

Trouble is, I am not really sure where the best point in my system to make the connection.

I only want it to provide a charge to the 2 house batteries, which I think are in parallel when the House Battery switch is in the "All" position??

Looking for comments.

I attached the diagram I did in order to understand my DC system.

Thanks...

 

[STB]

You could hook it to the output of that switdh so, when set to both, it charges both house batteries, but if either dies it can be isolated from the charger.

You could also replace the single source isolator with a dual source isolator, maybe a low drop FET one, and have it charge both banks.

 

[Mischief Managed]

I would get rid of the battery isolator and install an ACR in its place. I'd also put an ACR between the MPPT output and the two house banks. You could then get rid of the house battery switch and just use the manual switch function of the ACR to perform that duty, though you'd have to choose one house bank to always be the primary bank. That said, why have two house banks? Combine them and things will be much simpler.

 

[Iggy]

I would get rid of the battery isolator and install an ACR in its place. I'd also put an ACR between the MPPT output and the two house banks. You could then get rid of the house battery switch and just use the manual switch function of the ACR to perform that duty, though you'd have to choose one house bank to always be the primary bank. That said, why have two house banks? Combine them and things will be much simpler.

Also by combining the 2 banks, it will be less of a strain on the batteries when using the thrusters. I am not seeing the need of the 2 banks anyways.

 

[psneeld]

Be careful with switches...my MPPTs recommend battery connection before solar...not sure what might happen if that connection is broken with panels still hooked up....but there s a strong warning in my manual.

 

[jefndeb]

I don't have 2 battery banks..I have 2 house batteries connected in parallel...equals one bank....

 

[Mischief Managed]

I don't have 2 battery banks..I have 2 house batteries connected in parallel...equals one bank....

From the drawing the two batteries are set up as two banks and the only way to parallel them is to use the switch in the "all" position. If that is what you normally do, just connect the MPPT directly to either of the two house batteries with a fuse (sized to protect the MPPT wire, not the MPPT), near the battery.



If you replace the battery isolator with an automatic/manual ACR, you can manually connect the starting batteries to the house batteries so that the solar charges everything, you can use the house batteries to start your engines in an emergency, and your alternator charging will be MUCH more efficient. IMO, diode-based battery isolators have no place on a boat anymore. Losing 0.7 volts of charge voltage is very bad.

 

[jefndeb]

Very much appreciated advice, thank you.....and yes the House Switch normal position is "All", so I just have looked at it as a bank......