Residential Fridge battery run time
I know there are variables involved here on the manufacturer of the fridge, battery etc... But for those of you that have one assuming the standard group 27 battery the dealer gives you - how long can...
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On any given residential fridge, the Energy Guide sticker will give you a good idea of how many KWH (and thus how many amp-hours) it uses per day.
For example, this fridge uses 702 KWH per year, which would be around 1.9 KWH per day.
1.9 KWH/day would drain around 158 amp-hours from a 12 volt battery per day:
1900 WH/day / 12 volts = 158 AH/day
Note that the fridge will consume more than this amount on hot days, and less on cold days. It's just the yearly average amount.
The inverter you use to convert 12VDC battery power to 120VAC will also waste some power, so you might actually need closer to 200 AH/day (on average) to power your fridge.
Then you have to consider that lead-acid batteries shouldn't be frequently discharged beyond 50-80 percent, and now you need 240-400 AH of battery capacity.
That's for 1 day of operation between battery recharges. If you can't completely recharge your battery every day, then you'll need more battery capacity to keep the fridge running until full recharge is possible.
For example, this fridge uses 702 KWH per year, which would be around 1.9 KWH per day.
1.9 KWH/day would drain around 158 amp-hours from a 12 volt battery per day:
1900 WH/day / 12 volts = 158 AH/day
Note that the fridge will consume more than this amount on hot days, and less on cold days. It's just the yearly average amount.
The inverter you use to convert 12VDC battery power to 120VAC will also waste some power, so you might actually need closer to 200 AH/day (on average) to power your fridge.
Then you have to consider that lead-acid batteries shouldn't be frequently discharged beyond 50-80 percent, and now you need 240-400 AH of battery capacity.
That's for 1 day of operation between battery recharges. If you can't completely recharge your battery every day, then you'll need more battery capacity to keep the fridge running until full recharge is possible.
