Group 27 deep cycle battery + 2000W inverter

wa8yxm wrote:
If you are lucky .... an hour Likely less

That inverter needs 400 amp hours of battery support
two pair of GC-2 is recommended.. That's 400 amp hours with 200 usable
your group 27 is 100 (bit less) with 20-25 usable.

The fridge.. Well you did not say but look at the watts and divide by 10. yes 10 that's how many amp hours it will suck off the battery. So if it sucks 200 watts then it needs 20 amps of battery power

Both Dometic. and Norcold at one time made RV-Fridges using a ultra-high effiency compressors. 35-40 watts.. at 12 volts that's a bit over 3 amps. Door closed (Seems strange to have to specify door closed but the interior light adds a major draw)

A lot of "assumptions" being made..

2Kw inverter doesn't "need" 400Ahr of "battery support" (what ever THAT means).. If you mean 400Ahr capacity, you would be dead wrong because the OP did not specify just how long are they needing to run the fridge from inverter..

As I mentioned in my other post above, inverter will draw an average of 1Ahr-2Ahr per hr the inverter is turned on. 24 hrs of that and that is 24Ar-48hrs of battery not including fridge or anything else.. That certainly is not anywhere near 400Ahrs of "support".

Many apartment sized residential fridges will use about 90W at 120V and typical run time will be 20 minutes-30 minutes per hr..

So, lets say the fridge runs 30 minutes per hr at 90W level..

That is 7.5A at 12V (90W) x 12 (run time of 30 on and 30 off for 24 hrs) = 90Ahr

Add in the inverter loss (total time on, plus time with fridge running) of 48Ahr.

And we get 138Ahr of battery capacity required for the inverter and fridge for a 24 hr period..

Far less than your "assumed" 400Ahr of "support"..

Even if you went went with a far bigger fridge the results most likely will never come close to the supposed 400Ahr "support" you claimed..

And for the record, I AM using just ONE PAIR of 6V GC2s with a home fridge conversion.. ONE PAIR of GC2 gives me plenty of capacity to run my fridge for 24hrs, plus run the 30K furnace plus a few hrs in the evening of using lights and STILL have plenty of battery capacity left over..

Since the OP did not say how long they NEED to run the fridge and how much current the fridge uses plus details on the inverter and how much no load power it uses absolutely no way to blanketly say that the OP needs so much capacity "support"..

My suggestion is the OP should try their current battery in their driveway without shore power to see how long it runs.. Then they can make a better decision on how long they wish it to run and how much battery they will need for THEIR use.

Much better than giving some hokey number you pulled out of a hat because YOU don't like Home fridges in a RV..

Not everything must say RV on it to be used in a RV..

Not enough information to hazard a guess.

That being said, I have run a ten year old (not very efficient compared to new ones), 14 cubic foot (smallish “full size”), refrigerator for several days in 75-85 degree ambient temperatures and measured electricity consumption to be 2.0 kilowatt hours per day. Newer, more efficient refrigerators, larger/smaller ones, warmer/cooler environments, all make a difference. Oh, add 10% to cover the inverter.

That’s my beer fridge down in my man cave. 2.2 kWh translates to 183.33 Amp-hours, requiring 4.3 (that is, actually 5) of the common group 27 “marine deep cycle” batteries most travel trailers come with. Your mileage will vary, depending on factors noted above.

Gdetrailer wrote:

A lot of "assumptions" being made..

2Kw inverter doesn't "need" 400Ahr of "battery support" (what ever THAT means).. If you mean 400Ahr capacity, you would be dead wrong because the OP did not specify just how long are they needing to run the fridge from inverter..

Well yes. poor choice of words

Xantrex recommends two pair GC-2 for a 2000 watt inverter is what I should have said. Yes it will work on less. but Xantrex recommendation for the Prosione 2.0 was 2 pair GC-2 or 420 Amp Hour. of storage

You generally don't need more than a 1000 watt inverter to power a fridge. But if you are going to press an inverter close to 2000 watts for an extended period... 400 amp hours is barely making it. Certainly a fridge does not even come close to that with just a short surge and a couple hundred watts running.