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Q & A: battery capacity

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Most recent answer: 01/23/2016
Q:
I'm running a 400 watt inverter off an auto battery with 535 cold cranking amps to keep run a heat lamp for my dog .. I'm using a halogen 35 watt bulb .. how long will it last before it drains the battery
- Robert (age 28)
Dallas , TX, Dallas
A:

It's not the cold cranking amps that matter for this. It's how many amp-hours of capacity the battery has.  Since you're using a 35W lamp that requires about 3 amps at 12 V. Probably inefficiency in the inverter will then require a little more. So if you have, say, an 80 amp-hour battery it could run about a day.

Mike W.


(published on 01/23/2016)

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