Battery Pack

Battery Pack
How long will I get my battery?

I have a battery pack is 12V 7.2 amps. I want to run some LED Christmas lights are rated at about 7 watts. (100 lights) How long these lights run off this battery pack? The battery States "12V 7.2AH/20HR"

You can not say the information given. What counts is the number of watt-hours of battery can deliver and the number wattage of the lights consume. You have the use of light, 7 watts. The 12 V battery pack can deliver 7.2 amps but that's not necessarily the number of ampere-hours. This could be the maximum rated current in amperes. The amp-hour battery life could be more or less. Assuming that the battery can supply 12 times V 7.2 amperes for 86.4 ampere-hour, then you are entitled to 12 hours of operation. Actually not a bad guess. You could run the light all night, but would that to recharge the battery every day.

How to assemble a battery pack pt 1