On Dec 10, 4:02*pm, "Ralph Mowery" wrote:
"sid" wrote in message

...



80 watts at 120 volts is the same as 960 watts at 12v. add in the losses
in
the inverter, and you're gonna need a large battery
Nope !
80 watts is 80 watts
P = I * E
or *I = P / E
80watts / 120volts = 0.66 amps
80watts / 12 volts = 6.6 amps
I never figured I would ever get more than 1.5 to 2 amps from dry-cell
or alkaline batteries.
But I didn't expect it to be that poor.
Its not only for a display, its a contest !

The watts is the same for any voltage as you noted. *Just add some for the
loss in the inverter. *Might as well think of it as 10 amps to allow for the
loss in the inverter.

That means something the size of a lawn mower battery to run it for an hour
or so. * I have a rechargable to start a 5 KW generator. *It is rated 15 amp
hours. *It is about 4 x 4 x6 inches. *This would run your lights around an
hour and a half, maybe slightly more.

That is a little big. My 1st string of LEDs is rated at 18w and the
ones with color that blink are rated at 8 - 12w
I was figuring before I stated that I could get a respectable display
for under 25w and not have to invest in a marine battery ?