new question about this device..

[ejbpesca]

What sends 12V DC to this box? Is it the batteries or the shore power charger? (That's the two sources I have besides engine alternator).

 

[JimG]

That would be powered by the batteries. Since it has the breakers for your bilge pump and sump pump, it's probably wired direct to the batteries, bypassing any switches.

The shore power charger is only intended to charge the batteries.