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Electric heater circuit. Lesson Learned!



Jan 1, 1970
Now that winter is over I can turn off my electric heater... It also means I
can now set my Inverter/Charger on automatic again.

Here is the fault a found in my AC power panel wiring, I discovered the hard

Normally I only turn my Inverter/Charger to the charge mode when I note
that house battery bank is down a little.. This will usually be the result
of my frequent use of DC lighting while I'm onboard. The only other DC load
is the main bilge pump and I just leave the house battery disconnect OFF.
The only AC load is the electric heater with the thermostat set at about
50-60 deg, to keep things from sweating and take the chill off.

Back in Feb. I left the unit on auto charge for a day or so. When I
returned and opened the boat up I found that the AC shore power was off and
the Charger had switched over to Inverter and was heating the boat off the
800 AH house battery bank.. It must have been going on for a while because
the battery voltage was low enough that the Inverter was cycling off and on
at it's low voltage setting. I don't remember what the spec. voltage is for
that, but at least it did prevent the battery bank from dropping to a
critical level.

Upon investigating the cause of the shore power outage, I found that the
utility company was replacing utility poles and had been turning the power
off everyday for that past couple days.

Now I will have to do a little AC panel rewiring so the electric heater
isn't on the same breaker banks that is powered by the Inverter.

I'm even considering just a small trickle charger to keep the bank topped up
when I'm not onboard to monitor the much larger 150 amp charger. Or unleash
my Windbugger in the winter breeze (more like gales here).

If you have a similar Charger/Inverter, make sure you don't have your heater
on an Inverter powered circuit.

Len Krauss

Jan 1, 1970
Several people I know have cut the buss bar at the last connection and put
things like shore powered A/C and heaters on that segregated breaker so that
the inverter can't power them.