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Marine Fridge 12V vs Regular 115V with inverter

Posted: June 18th, 2019, 9:40 am
by Brnn
Ok Guys, I discovered the fridge on my 38 convertiable was 115v only (must have been replaced by previous owner or maybe never was 12v) after my first year of use. I like to have my fridge working when im out and im not running the generator all the time to do it.

I can buy a bar fridge many places for cheap and put it on an inverter. The whole package might cost $450. When i looked at the dedicated marine 12v fridge they are like $1200 !!

Has anyone used a regular fridge on an inverter?? If so how does it work for you on battery power? Has anyone had both that they can compare. What are some of the more efficent models out there for in 12v.??

Cheers!
Eddy!

Re: Marine Fridge 12V vs Regular 115V with inverter

Posted: June 18th, 2019, 11:26 am
by km1125
I have a 115v fridge now as a temporary replacement for my normal 12v/115v fridge that failed. I am considering putting an inverter on it so we also have it running while on the hook. Haven't done that yet, but thought it through.

First, either you need to get a more expensive inverter which includes a transfer switch, or you need to move the plug from the "normal" plug to the "inverter" plug when you're disco'ing from shore power. Lots of good inverters can do this but the cheaper ones don't.

You also have to realize that the compressor in the 115v-only fridges are not made for a marine environment. To much bouncing around, particularly slapping waves, will cause the compressor to fail much earlier than normal. If you don't bash waves much this may not be an issue, but if you do, then consider that 115v fridge a temporary solution.

You will lose a little efficiency going through the converter. Expect about 20% more current draw than the fridge is rated for.

Re: Marine Fridge 12V vs Regular 115V with inverter

Posted: June 18th, 2019, 12:35 pm
by Midnightsun
Many do this however as mentioned the efficiency is not as good. Personally things like this turn me off when shopping for a boat. First thought that comes to mind is what else did they cheap out on. Just my personal opinion, a 110v inverter run fridge will work fine.

Re: Marine Fridge 12V vs Regular 115V with inverter

Posted: June 18th, 2019, 2:16 pm
by darrenlife
The previous owner of my last boat had replaced the failed 12/120V fridge with a 120V and he subsequently ran the generator when away from the dock. I installed a 2800W inverter with a shunt for the first 4 years with the 120V fridge for four years and can tell you it would draw 11A DC. I eventually replaced the 120V with a proper 12/120 and the consumption dropped to 6A DC as I no longer needed to run through the inverter.

I agree with Hans that I'm always leery when making a larger purchase from someone taking shortcuts but it can be done with a sacrifice of increased generator usage.

Re: Marine Fridge 12V vs Regular 115V with inverter

Posted: June 18th, 2019, 2:48 pm
by g36
I ran a ac under counter unit for additional space for quite a while it will work fine just have to size the battery bank properly. 10-11dc amps while running as mentioned is spot on. Sometimes you just got to break out another thousand. :-D
Here's what I have in my 405 now it comes with 3yr warranty. Have been very happy with it keeps ice cream solid and interior space is 8.1cuft.
https://www.defender.com/product.jsp?id=1262894

Re: Marine Fridge 12V vs Regular 115V with inverter

Posted: June 18th, 2019, 7:32 pm
by bud37
The only thing I got is the same advice I give to everyone considering using household appliances on a boat.......just make sure they are electrically compatible with marine wiring as far as grounds and neutrals.....I am sure most are now, but it never hurts to have it looked over first.

I do agree with the others here also, that the marine versions are probably the best choice in the long run, even though the initial cost seems high. The ability to go from 12 to 120 seamlessly will pay off. The ah usage will be substantially lower as well.

Re: Marine Fridge 12V vs Regular 115V with inverter

Posted: June 19th, 2019, 9:17 pm
by Viper
Several OEMs installed AC only fridges for years, some are probably still doing it, depends on the boat and intended/designed use I guess. My previous boat had an AC only unit to which I added a dedicated inverter with a selector switch to select between shore and inverter just for the fridge. Worked great. Never had a power issue but I had a large bank as I spent a lot of time on the hook.

If you're going the route of an inverter for the fridge, spend a little extra and get a pure sign wave unit, your compressor and fans will thank you for it.

Re: Marine Fridge 12V vs Regular 115V with inverter

Posted: June 19th, 2019, 11:48 pm
by tomschauer
also keep in mind when buying an inverter for a household appliance, the inverter should be rated for 150% of the running load amps of the compressor equipped appliance to be able to handle the start load.

Re: Marine Fridge 12V vs Regular 115V with inverter

Posted: June 20th, 2019, 6:50 am
by Viper
That's usually the case with most units on the market now, usually 200% for short startup spikes. On my previous boat, I added a large capacitor to the compressor which helped drop the startup load dramatically.