Let's do a little math.........

How much power does a house battery have?

Hmm....It says 330 amp-hour at a 20 hour rate (not 500 amps all at
once). Let's pretend it's 300AH for this lesson. We gotta fudge
somewhere, this is math! It's a 13.8V battery but loaded up let's say
12V to keep it simpler. V x AH = watt hours (not kilowatt hours like
at home). 12V x 300AH= 3600 watt hours of "house power" in the bank.
(Your AH may vary, look on the battery.) If we draw 1000 watts, it
should run 3.6 hours (but it won't make it quite that far because 1000
watts divided by 12V = 83.3A plus the losses in the inverter, probably
90A. 90A, for reference, is a running starter turning over a dead 6
cylinder diesel engine. How long can we crank the dead engine before
we're out of juice? Is the picture coming in any clearer, yet?

2000W is 180A at 12V! Make damned sure the house battery wires are
size 000 wires! 000 wires is 200A continuous, which is what a 2000W
inverter is gonna pull, if it can....continuously, not just a pulse
like the starter needs to get the engine moving. Wow...180A seems
like a LOT of current. It is!

I'd bet we could pull the A/C with that monster about 30 minutes off
an inverter...give or take 20 minutes. Do you see why? There just
isn't that kind of power available to start with unless you're on a
diesel submarine with 6,250AH battery cells that are about 6' high, 4'
wide and 3' deep. Great ballast, though. Causes a diesel sub to SINK
if we let the air out of the ballast tanks! They got lots more than 6
cells and run lots higher voltage than 12V, too. It's more efficient,
as Tom Edison found out from Nikola Tesla, who invented your AC power
system.

NOTHING is funnier than watching a boater with a new 4KW Heart
inverter carrying his electric heater down the dock with a big smile
on his face.....(c;

Larry W4CSC/MM
S/V Lionheart
with 700AH battery banks and a more reasonable 500W inverter.....


On Mon, 06 Oct 2003 04:41:29 GMT, "John Tretick"
wrote:

Hello Group,
+
I have a 24" Bayliner Cierra 2001 and I am interested in using AC when not
at port. No place to install a generator, so I'm thinking an invertor with
a batterstore. Possibly increasing my batteries to 3 and wiring in GFI
circiut to power mixers, inflators , hairdriers, etc.. when I'm anchored.
Northern tools sells a sealed Marine invertor for 399 its 3000/1500W which
works for my purposes.. doubt it would run the AC..
but I guess I'd have to get a larger on for that..

Has anyone installed this redundant power source defore? I'm curious how
long you can run on it without depleting one battery..
Actually thinking about installing a third battery for this purpose.

Thaks,

John





Larry W4CSC

3600 planes with transponders are burning 8-10 million
gallons of kerosene per hour over the USA. R-12 car air
conditioners are responsible for the ozone hole, right?