Need Advice - Refrigerator on separate Inverter

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Hi All! I have an older Class A Motorhome (1986 Champion Titan Signature). The previous owner had installed a residential refrigerator that runs on AC/DC only. So No Propane. Its never been a huge issue as we have mostly went to campgrounds where I could plug in. The setup itself is there's a toggle switch from AC to DC for the fridge, so it has it's own inverter and battery. That battery I believe is tied to my larger battery bank that is located up front of the RV. This year we have boondocked a good amount. After this last trip I decided something needs to change as the battery drains very fast. I have to run my generator ALOT/bring a spare battery, etc just to keep the fridge from faulting out. All the things you would imagine needed to keep enough power to run the fridge.

Anyway, I had resound to just buying a new fridge and getting one equipped for Propane. After looking into that, there seems to be a good amount of options out there to stick with the residential fridge setup and just go with Lithium batteries or other upgrades. I am not interested in going solar. I do have an 120W portable solar kit that I hardwired to my battery bank to help maintain things. I am leaning toward just putting a Lithium battery for the dedicated Fridge battery as it's got long life and would charge fast. It's just a large cost initially I want to be sure its a good option.

Does anyone have any advice/input on this? Much appreciated!

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2oldman wrote:
I don't understand your reference to AC/Dc for fridge. A lithium battery is not going to solve your problems, it's still just a 100ah battery from which you can draw a bit more power than an acid.

Solar is a really good idea for this problem. In fact, it's about the only idea unless you like hookups all the time or running a generator.

Here's a few previous posts on the subject:


pros-cons v. gas2016
boondock with residential refer 2018
household refer and inverter2009
Household refer Class A 2009
residential fridge- boondocking 09
Residential refer Class A 2010

Thank you! Lots of good info in there. I'm not married to Lithium it's just what I found some people had luck with. One of the main selling points for me was the longevity of the battery itself along with being able to charge up quickly when running the generator.

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I would not mix the lithium with the other batteries. I would replace ALL the house batteries with lithium. Otherwise you will be managing two different banks with different charging etc. Verify the charging system specs match the lithium battery before you purchase. Even with the increased usable capacity you may still need to increase capacity until you are comfortable withe the power duration. I would want capability of 48 to 72 hours minimum between charging even if you charge daily. This capability for if something goes wrong. You will know more what you need after a few nights off-grid.

[theoldwizard1]

rcksblr wrote:

Anyway, I had resound to just buying a new fridge and getting one equipped for Propane. After looking into that, there seems to be a good amount of options out there to stick with the residential fridge setup and just go with Lithium batteries or other upgrades. I am not interested in going solar. I do have an 120W portable solar kit that I hardwired to my battery bank to help maintain things. I am leaning toward just putting a Lithium battery for the dedicated Fridge battery as it's got long life and would charge fast. It's just a large cost initially I want to be sure its a good option.

Does anyone have any advice/input on this? Much appreciated!

Do you boondock much ? If so for how long ?

You still have to decide if you want a DC only refrigerator or do you want a residential unit and then an inverter. The residential refrigerator will cost less, but then you have to adding in the cost of the inverter. Most DC only refrigerators have an optional AC power supply that you can use when on shore power, but that is not adequate for recharging a dedicated battery.

If you have no interest in an inverter for the rest of your coach, perhaps a separate battery just for a refrigerator but it might be a good option ! If you only boondock for a couple of nights, I think a 30Ah-50Ah refrigerator dedicated lithium battery would be adequate. Buy a dedicated lithium battery charger and wire it, the battery and the refrigerator positive leads together. Same for all of the negative leads together.

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jdc1 wrote:
100amps/day is what a 20 cubic fridge/freezer uses. One $899 battery will work for a day. You'll need a different charger.

The fridge is a Danby 7.4 Cubic Feet. Sticker says 344 kWh annually. So if I do the math that is somewhere around 80 Amps/day. Which is a lot, no doubt.

My thought in this application for the Lithium battery would be that I could run the Generator for a few hours a day to recharge the battery to keep things maintained while camping. I also have the solar panels I could keep plugged into the battery as well while not running the generator. I do have two separate standard RV/Marine batteries (845 CC amps) in the battery bank up front that are tied to the Fridge battery so that would help as well.

[2oldman]

I don't understand your reference to AC/Dc for fridge. A lithium battery is not going to solve your problems, it's still just a 100ah battery from which you can draw a bit more power than an acid.

Solar is a really good idea for this problem. In fact, it's about the only idea unless you like hookups all the time or running a generator.

Here's a few previous posts on the subject:


pros-cons v. gas2016
boondock with residential refer 2018
household refer and inverter2009
Household refer Class A 2009
residential fridge- boondocking 09
Residential refer Class A 2010

[jdc1]

100amps/day is what a 20 cubic fridge/freezer uses. One $899 battery will work for a day. You'll need a different charger.