NW Explorations
GREY LADY OPERATING MANUAL
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supply, typically 30 amps.
Here are some estimates of AC power consumption for typical appliances:
Each Air Conditioner
12 amps
Cooktop
10 amps
Water Heater
15 amps
Inverter
up to 22 amps
Hair Dryer
12 amps
TV
1.5 amps
Coffee maker
10 amps
Microwave
10 amps
The Inverter System
As we said, the Inverter system is used to provide AC to the boat when there is
no shore power. It is wonderful, for example, to use the inverter to make a pot
of coffee when the engines are running and you are underway, or to watch TV in
a quiet anchorage, or use a hair dryer for a few minutes in the morning. But for
long-period use of AC by large appliances, the engines must be running or you
must have shore power available. That’s because the inverter’s batteries store
about 100-150 amp-hours of electricity, that is, they can produce 100 amps for
one hour, more or less.
Now the microwave, for example, will draw about 100 amps of DC when using the inverter to run it, so in six minutes you
use one-tenth of an hour at 100 amps, or ten ampere- hours. That means that in six minutes, you’ve consumed 10% of
the house batteries’ stored power. That’s okay. But what if you want to cook a roast for 30 minutes? You used up half of
your energy on that one job alone! That’s too much use for the inverter, and the propane stove should be used.
For a short task, the inverter is great: no starting the generator, no noise, no fuss, the power is there. If the engines are
running, use it all you wish, as long as you don’t try to do two big jobs at once: The inverter can only produce 3,000 watts
of energy at a time. So the inverter is only wired to the outlets, refrigerator, and the microwave. It will not run the water
heater or battery charger. Boat heaters, particularly, should never be run by the inverter; start the generator instead!
But in addition to making AC out of DC, the inverter can do the reverse! If there is AC available from shore power, it will
charge batteries! You tell what the inverter is doing by its control panel. The little lights indicate its status.
To activate the Inverter push “Inverter” button on the
Magnum
panel.
INVERTER L.E.D. STATUS LIGHTS
“PWR
” “is lit if there is AC available for battery charging (from shore power or the generator). “
FAULT
” will light if the
system detects a problem (this is rare): See the manual.
“
CHG
” will blink rapidly just after shore power or the generator comes on, indicating the unit is getting power but is not
yet charging; it will be steady on if the Inverter is charging the batteries; off if the charger is not on nor is it charging; and
blink slowly if the charger has insufficient AC power to charge the batteries in which case you will need to reduce the AC
load or start the generator.
“
INV
” will be “ON” if the inverter is on and supplying power to AC equipment on the boat; it will blink slowly if the
inverter is on, but there is no equipment drawing power from it; and it will be off if the inverter is not run.
Inverter Control
Buttons
: Touch a button to “wake up” the display before anything will work!
On/Off Charger
: Controls the charger function of the inverter. Should be left “On”.
On/Off Inverter
: Controls the inverter function. Should be left “On” except when at a moorage for long periods, such as
overnight or longer, when the generator is not on and there is no shore power, to avoid depleting the batteries in case an
AC appliance or light fixture has been left on.
Magnum panel in stairway
near electrical panel
