12v DC fridge

[djhassoonew]

I have 12v DC fridge of 72 watts as you can see in attachment file aswell.

Could you please tell me how many solar panels and batteries I need to run this fridge for 24hours?

Thank you

[SunEagle]

Depends on if that fridge draws 72watts continuously for all 24 hours or not.

If it does then it will use almost 1800 watt hours a day. ( 72 watts x 24 hours = 1728 watt hours).

The battery system should be sized so that you never drain it more than 25% a day so that would mean 1728 watt hours x 4 = 6912 watt hours. So round up to 7000 watt hours.

A 12 volt battery that can deliver 7000 watt hours would be rated ~ 600Ah ( 7000wh / 12v = 583Ah)

For a 600Ah battery you need about 60Amp of charging or 720 watt of solar panel ( 60a x 12v = 720 watts). But depending on where you live and figuring in some losses you will need more than that so say 900 to 1000 watts of panels.

Then an MPPT charge controller that is rated 80amps.

Now that calculation is maybe based on worse case of full load running all 24 hours. If the DC fridge uses less watt hours then you can use a smaller battery system and less panel wattage. But without knowing what it actually uses it would be hard to size your solar / battery system. If you make it too small you will kill your batteries and shut down the fridge.

[Sunking]

Panel wattage = 900 watts
12 Volt Battery Capacity = 720 AH or about a 400 pound boat anchor
MPPT Charge Controller = 80 Amps

[Mike90250]

That's why I went with inverter, batteries, and an energy star fridge, More fridge for about the same money spent