Compact fridge and inverter

Compromises compromises...as long as the owner is tickled to death, why worry...?

Going to an absorption fridge is, in my opinion, a mistake.

I have been chewing all this input over for the weekend, amps and wire size, reserve capacity. Thinking about running wires and mounting fridge. Maybe eventually adding a solar panel.

So for about $600 to $700 I am gaining 2 cu ft of fridge and not having to worry about parking level! Plus will likely be about 3 days of fabricating, running wires, collecting parts. Maybe not worth while?

I am grateful for all the input and hopefully someone else has found the info useful. But tomorrow I am going to start on returning RM 2410 to its rightful home and learn to live with it.
Jim SW FL

I had a Mini fridge rated at .8a at 120Vac for a bit, ran it on the system for a while and gave it to the MIL because the freezer was too small. I wouldn't even think of trying it on the Grp 27, that's a good way to kill a battery very quickly. Even quicker for our five year old battery.

New and fully charged our grp 27 with 95 Ah was pressed to run just our 12v absorption fridge pulling 8 amp overnight. It never cycles but also has no start up surge or needs a inverter. The cycling would help but the start up surge will be harder and harder to handle as the battery loses voltage.

That surge takes a chunk out your battery's power every time. Eventually the battery will be low enough that the compressor doesn't start and the continued attempt will drain the battery the rest of the way. I've watched it happen testing the little A/C on a 250 Ah 8-D. It damaged it and the 3000w inverter, surges are nothing to ignore. Starting and marine batteries can't take that kind of abuse and it will shorten the life of even GC batts.


8 amps or .8a at 120Vac is on the low end for mini fridges. The majority pull 1.5a at 120Vac and have even higher start up surges to deal with. Only one pulls less than .8a and it cost a extra $100 for that .16a savings. That's a extra 1.6a not coming out of your battery. ( mini cubes are almost always 1.5a @ 120Vac)

Just adding info to hopefully help you set it up.

westend wrote:
You will need more capacity. I wouldn't rely on the vehicle charge line to charge batteries to 100 percent SOC. That means you may park with less-than-full battery. Hence, the loss of food.

I would be also concerned with a loss of battery. A single gr29 holding - as we established - about 90-100 AH, will cycle between 50% and 85-90%, possibly dropping below 50% regularly. Not a good idea even if it were a real deep cycle battery - or whatever is normally labeled as deep cycle.

Getting full 100% would be difficult even without that fridge though. This is is the nature of charging, last 20% are slow. Fridge would aggravate the situation.

I would try that 2/0 in a heartbeat with the existing inverter before spending money.
Worst case the wire is in place for the new inverter.

jjrbus wrote:
I am shopping for and trying to size an inverter. I do not have wires or fuse yet as I do not know what size I will need.

Length of wire should be less than 3 feet each way. I do have some 2/0 welding cable, seems a bit much for a small inverter.

The wire size is OK if you have it. You will need a minimum of #2 AWG and a 150 amp fuse. I'd recommend a 1000W inverter, minimum, and a quality product, not a price leader that may not handle the surge of the fridge compressor.
You should also ask yourself if the price of losing a chest of food is worth the additional price of adequate battery capacity. You will need more capacity. I wouldn't rely on the vehicle charge line to charge batteries to 100 percent SOC. That means you may park with less-than-full battery. Hence, the loss of food.

I am shopping for and trying to size an inverter. I do not have wires or fuse yet as I do not know what size I will need.

Length of wire should be less than 3 feet each way. I do have some 2/0 welding cable, seems a bit much for a small inverter.

jjrbus wrote:
I will experiment with this and if the GP 29 is not sufficient I will go to the 2 GC.

Took a bit to get the battery info.
Any chance you can post the 12v wire size and length?

Need a connection to carry 120 amps and maybe a bit more with low voltage drop to ensure maximum surge performance.

As an alternative put the voltmeter on the inverter 12v input. Monitor the voltage stays above about 11.8 as you turn on the fridge. Although voltage can drop out faster than you see indicated.

jjrbus wrote:
People are skipping what I am saying, I will be driving often (charging battery) and running the generator or tied to a power poll. So all I actually need is to keep the fridge cold over night

Daily driving and generator have come up when - after 3 pages of responses? Forgive those of us here that are not psychics :)... Then they will hopefully forgive your skipping what they are trying to tell - your battery is way too small and is not even the right type for a coach battery.

Power poll you have mentioned for the first time now.

For your own good, I hope you will be running generator same or even more often as you drive, i.e. all the time while on the camp, unless hooked up to grid. Without constant source of power your single 100 AH battery will have a hard time charging above 90%.

If you avoid opening fridge in the night, it will remain TAD cold for 10-15 hours. Depends on the ambient. Won't keep initial 40F but will remain below 77F by the morning. A small freezer tray of a dorm fridge will probably have water pouring out, by the morning. Standalone freezer - especially a chest freezer, full of frozen items, is a different thing, it can stay cool longer because of the cold accumulated in all those items - but it takes longer to freeze them too.