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-   -   12v compressor vs boondocking (https://www.airforums.com/forums/f425/12v-compressor-vs-boondocking-230138.html)

GeocamperAS 12-13-2021 08:59 AM

12v compressor vs boondocking
 
Does anyone have experience and/or knowledge of how fast a 12v compressor refrigerator will drain a battery if boondocking?
Thanks

richard5933 12-13-2021 09:13 AM

Lots of variables in this question.

How big the battery bank?

How big the fridge?

It's a math problem. Figure that the fridge will have a 50% duty cycle. Take the usable capacity of the battery bank and divide by the current draw from the fridge.

For example, if you have 200 Ah of capacity in AGM batteries, that gives you a 100-amp usable capacity.

My 12vdc compressor fridge draw approx 5 amps when the compressor is running. Figuring a 50% duty cycle, that means it draws 2.5Ah.

If I had nothing else running (which is never the case) the fridge itself could run for 40 hours on the batteries.

Of course, that doesn't consider the extra load incurred by opening the fridge to retrieve food, cooling down food you bought and put in the fridge, extra load due to warmer weather, etc.

On our coach where we have the 12vdc compressor fridge we boondock quite a bit. If we're careful with things, it we usually consume about 75 Ah in 24 hrs running the fridge, a few LED lights, the water pump, and the roof vent fan. There have been days we've done better and some where we've done worse.

This is all just an example though, as you'll need to calculate your particular situation incorporating whether or not you have solar, how much you draw from batteries for other things, etc.

uncle_bob 12-13-2021 09:23 AM

Hi

Compressor fridges average somewhere between 1.5A and 7A "depending". Battery banks can be anywhere from 80AH (= stock flooded cells) usable on up past 400AH ( four lithiums). So:

7A fridge on 80AH battery will be "ok" for about 11 hours.

1.5A fridge on 400AH will do ok for a bit over 11 days.

Very much a "that depends" sort of thing.

Bob

GeocamperAS 12-14-2021 07:08 PM

Thanks for the input. I will do my homework.

Stormalong 12-14-2021 07:25 PM

Works for us. We have 400 amp/hrs AGM batteries (200 amp/hrs usable), 400 watts solar. Our NovaKool refer plus electric coffee maker in the AM uses about 70 amp/hrs, then even with partial sun we usually get full charge by end of day. We have not used our generator in over a year, but still carry it in case. We often boondock for a week at a time in Washington state. I'm happy to have stable refer temps in hot or cold weather.

mrdes8 12-15-2021 10:11 AM

We have gone with a Dometic CRX110, very similar power use to other responders. 250 ah AGM so 125 available. 400 watts solar or 45 amp Boondocker converter. Challenging days are frig and furnace together. Victron BMV 712 is very helpful keeping track of power in and out, gotten down around 60% battery a few times, had to run the generator once in 2 full years of use, around 150 days. Bottom line , if we're careful we can go 3 days batteries only.
Good luck, Mark D


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