Ask PYS: PowerEntertainment

Tom – Shore Power, on Jan 27, 2014 asked:

I have been away for the last two months and due to Thunderbird redoing all their slips where I was docked, I am on the hard for the winter. All they had for power was 15amp. I plugged in the shower power system and hooked up a few minor boat heaters and little fans. They were plugged in to the electrical outlets so they should work on AC. My friend was to go by and make sure they were running. He called to say that breaker on the outdoor power pole was tripping. So I suggested turning the inverter off. This turned off the AC, which confuses me. I think it is the inverter drawing all the power, then tripping the 15amp breaker. I am thinking there must be a way to bypass the inverter, maybe a standby mode where the AC plugs will still work. As well, with the battery charger off, am I risking discharging the AGM batteries and the other batteries as well?

Recall that 15 amps of shore power is very limited. You'll need to pick and choose what can run simultaneously.

What needs to happen is a few things:

Your inverter/charger needs to be set to the following:

  1. Inverter: off – Never have the inverter on while you are not on the boat.
  2. Charger: on – The charger needs to be on to maintain the AGM batteries.
    • Charge rate: 20% or 40% - This will limit the amount of power the charger can draw.
  1. AC Heaters need to be put on position 1 or at most 2 for the fan speed. Even at that setting, you'll maybe be able to run two fans at the most.