mains fridge from inverter

[Rory_McGee]

I have a small mains powered domestic fridge with a label on the back that says it's 75watts. It works fine when plugged into the mains.

I'm trying to operate it on my boat from a 12v DC to mains inverter which is rated 350w continuous and 600w peak, but it seems to overload it.

The inverter is new and works ok with other smaller loads.

Anyone tried this before?

I know there may be a fairly high start up current required to get the fridge going, but surely it wouldn't be more than 600w?

Any advice would be most welcome.

Rory

 

[iangrant]

The start up for a domestic fridge compressor will be more than 1Kw. May pop your inverter if you keep trying.

Ian

 

[quintella]

I am currently running a small domestic off a 700W inverter whilst at sea/anchor and have had no problems. Almost 72 hours has been the longest stint away from a marina berth and cold beer all that time. A smaller inverter did "pop" due to the start-up current.

This application is in use in Spain and is running more than you'd experience in the UK. I switch the fridge off if I run the PC (desktop), and again no defrosting problems over an hour or so.

Like Colvic, I experienced trouble with a 12v fridge which Danfoss have confirmed is a mains compressor with a small modification and a "type" of inverter built into the control box for the compressor. You should see the heatsinl for it. At £160 I chose to get a domestic 65litre fridge and saved £85 which is a longway towards the inverter which can also power handtools etc..

I'm not going back to a 12v fridge at some £600 a time!

Peter

 

[Teddy]

Is the inverter wired directly to the battery, or is it via a cigar lighter plug? If the latter, it could be the contacts are not man enough for the job. Good luck.

 

[jfkal]

Agree.

 

[oldharry]

Invertors take a pretty hefty current from the battery, notionally an amp for every 10watts mains power. The compressor motor may need as much as 100 amps from the battery to start it even if the consumption drops to 7 or 8 amps almost immediately. A good bit more than the 'cigarette lighter' plug can cope with, and a lot more than a 300 w invertor will push.

 

[ccscott49]

75 wats, is it's continuous running consumption, + 6 amps at 12 volts, it's start current is considerably more. I would expect in the region of 500 watts or more, with the subsequent current surge. 500 / 12 = +40 amps at 12 volts, so your wiring to the inverter from the batteries should be able to handle this current, it probably wont without allowing a large voltdrop, which will trip the inverter, because it gets less than its designed voltage, which causes it to trip to save your batteries from being completely flattened, check your wiring, I would also invest in a much bigger inverter, you may need it. I agree with all the other stuff, I use a domestic freezer, in the med, which does me very well. I wont be buying anymore "marine" fridges, but my boat is big enough to use the small domestic type, some smaller boats aren't.