110v Residential fridge install

Almot wrote:
Gdetrailer, 0.768 KWH is 65 AH. This is closer to what one could expect. And, this is post-inverter, so add another 5 (7?) to this number, to get the battery draw. 70 AH. Maybe 75 AH. This is at 30% cycle. Did it run 30% at 100F?

Now, the draw less than on the nameplate is one thing, but there is also a start-up spike way higher than a running current, with these 120V machines.

Fridge seems to run consistently at 20 minutes per hr regardless of the ambient temps for 70F-100F range (varying maybe 1 or 2 minutes at the most).

Startup spike even though I did manage to measure it at about 10A at 120V is such a short duration overall (microseconds) that it really is not worth even worrying about.

Granted the .768 KWHr is not including the inverter loss, however I consider the inverter “loss” as a “wash”.

Many folk who like to point out the “bad points” of a home fridge (like inverter losses) also conveniently “forget” that a RV fridge ALSO USES 12V for the control board AND the gas valve so in reality you can EASILY remove the inverter overhead loss or “waste” out of the equation..

If I remember correctly the RV fridge control board uses about .150A (150ma) 24/7 and the gas solenoid can use upwards of .5A (500 ma), perhaps more as long as the burner is on. Not to mention the spark igniter board current draw each time at the beginning of ignition. So the control board uses 3.6 Ahr for 24hrs and if we assume burner running 20 minutes per hr that would be 12Ahr for 24 hrs.

So a RV fridge can use at least 15.6Ahr of battery per 24 hrs (not including the igniter).

In my case, my Tripplite has an no load idle current of 2A at 12V (you can typically add in the no load idle current of the inverter and count that as your inefficiency of the inverter since idle current typically adds to whatever the load of the inverter is and varies a little from no load to full load).

So if I allowed the inverter to run all the time (as you would with most inverters) that would be 48Ahr draw. By using the load sense feature of my inverter it only runs the time the compressor is running or 8hrs which would be 16Ahr.

Add 16Ahr to my fridge of 65Ahr I need to plan for 81Ahr for 24hrs.

So even using my numbers of 81Ahr I would be only adding 65.4Ahr to the battery load ABOVE what a RV fridge would use.. pretty much easily taken care of with only one pair of 6V GC batts

This number is well within the capacity of one pair of 6V GC batteries, I am using one pair of Sams Club GC batts with 210Ahr capacity.

Granted 50% DOD of that is 105Ahr so I have a leftover capacity of 24Ahr. KEEPING IN MIND THIS IS FOR A 24 HOUR TIME PERIOD BETWEEN CHARGING.

Also keeping in mind very few people TRULY go 24hrs or more without the need to run a generator for high draw AC things like microwaves, A/C and such.

In my case, I typically camp with shore power but I DO run the fridge from battery while driving AND OVERNIGHTING. While driving the charge line helps to keep the batteries from being heavily discharged and we typically stop for the night at 9 PM and get back on the road at 6AM the next morning (about 9hrs).

So I would expect 3.357Ahr per hr and 9hrs for overnighting would be 30.375Ahr used by my fridge for the night.. This leaves me with 74.625Ahr of usable capacity left (which I can run the furnace and lighting overnight).

All but the hardcore no gen boondockers would not have any real issue since many often run their gen in the morning to make coffee, microwave breakfast and such then run gen for lunch or supper and in the evening.. As I see it only those folks who are “weekend” no gen warriors who do not take or run a gen for a two or three day weekend would be “affected” by having a home fridge.

I personally would not be afraid to boondock for a few days with my setup since I KNOW I will be running a gen for microwave and or A/C usage (I am not into the boondocking thing, I “camp” to get away from work and the idea of toting additional freshwater, dealing with getting rid of waste water and constant watching over these “systems” is more work than I am getting away from).

An hr in the morning and hr at noon and an hr during the evening of gen time would be all that is needed, for most folks it would only require running their gen an additional few minutes...

If some solar were added one might be able to get the gen run time down to two hrs total for each day..

On the flip side of things, I use very little propane, it has taken me 8 years to empty ONE 30lb cylinder! We only use propane for water heater, furnace and if we cooked inside a lot the stove… The previous trailer we used one 30lb cylinder every couple of years.

We only get a couple of weeks a year to camp, so I want to spend very little time messing with boondocking like maintenance (water systems and battery stuff) and enjoy doing very little (or as little as possible like sitting around a campfire)..