OT: question to electrical guys...

 
Now that we are back up and running, I want to look toward next time. I
apologize for not remembering who it was here shooting me info last
week, but I did listen, didn't back feed the box. But either way with
the limited access and limited bandwidth with the sprint card/lack of
sleep/heat/water, etc... I didn't notice who it was helping me.. Sorry.

On to my question...I am considering making a string of
emergency/convenience lights to run when the generator is not, I would
like to run them off of a DC car or marine battery (if I can) and an
inverter to supply the 110 to 10 23watt florescent lights (they call
them 100 watters), I would charge the batteries when the generator was
running, a few hours a day.

Is there a quick calculation I can use to figure out how long a car
battery can run say, 200 watts of ac? Thanks.

 http://www.windsun.com/Batteries/Battery_FAQ.htm#Amp-Hour%20Capacity

i have a large towmotor battery.
it is not efficient but works well for my needs

 opps sent too soon
car battery ~40 amp hours
deliver one amp per hour for 40 hours,
2 amps for 20 hours
4 amps for 10 hours
ect

amps * volt = watts so
40 * 12 = 480 watts before needing charging

towmotor batteries are much bigger

 On 11/8/2011 9:10 PM, john wrote:

Thank, the link plus a quick google refresher in Ohms law, and the
figures above are what I was looking for. I got it from here, thanks...

 On 11/9/2011 9:38 AM, JustWait wrote:

I came to the conclusion that my 200 watts of lights should run about
2.5 hours on ~40amp hours. Does that sound about right?

200 W / 12 V = 16.5 A

40AH / 16.5 A = 2.5 H

Thanks again... It's been a long time;)