"sid" wrote in message
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On Dec 10, 3:24 pm, "charlie" wrote:
"sid" wrote in message

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I have a project to decorate the family "Little Red Wagon" with
Christmas lights. So I stated experimenting with LED light strings and
battery combinations. I finally decided to use an Inverter and not
cut up any light strings. The LED light set that I found has 80
lights and the specs state it uses 12 watts. So as a test I connected
two 6v lantern batteries in series and ran the leads to the inverter
(rated at 100watts), connected a lamp with 40 watt bulb.

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 !

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oops. i doubt you could get 6.6a out of a dry-cell battery for long. try a
car battery.

they also make led xmas lights that work off a small battery pack. i
recently saw a lady wearing some, that were hooked up to the ones she had on
her baby's stroller running of a small c cell battery pack.