Fridge Inverter

[300sflyer]

I have a DE-251E Norcold fridge that runs great on 110V AC, but will not switch over to 12V when disconnected from shore power. I have diagnosed the problem, and have determined it is the oscillator. Fixing the fridge is not an option, and new ones are far too much $$$.

I would like to mount an inverter, and have the fridge run off of it all the time. This way it would run regardless of whether or not the shore power was connected. The battery charger will keep the batteries topped up when the boat is plugged into shore power.

My question is, how many watts does the inverter need to be? 500? 1000? Or can I get away with 100W? If the fridge draws 4 amps on 12V, is that not just 48 watts?

Thanks!

 

[bruceb58]

Yes, the compressors in those are pretty low wattage. I would buy a larger one than you need just so it can handle the inrush current for when the compressor starts up. The bigger question is if you need to get a pure sine wave inverter or not.

The part that isn't working is actually an inverter itself except that it just converts the 12V DC to around 22VAC.

 

[300sflyer]

My research found 22V AC too. I suppose 100 watts would be plenty then. Could I use the factory fridge10 gauge wire to power the new inverter itself? This would save having to run new cables to the battery.

 

[bruceb58]

I would think that would be plenty.

 

[Scott Danforth]

I run my laptop on a 100 watt inverter and can trip the circuit breaker if the battery on the laptop is completely dead. I personally would look at something a bit larger. most are rated at intermittent use with continuous use at half their rating.

while I agree the 12 volt side is 48 watts, however what is the 110VAC side drawing. this is the side you need to power since your 12 volt side is dead.

 

[gm280]

300sflyer, if you isolated the bad part section to the oscillator, when not fix the oscillator and happy boating again? I mean the piece parts can be that unique or expensive. I doubt it is any special wound coils but probably the driver transistors gone. That is what usually goes out in them. And those transistors can easily be bought at a ton of electronic stores. Just a thought... :noidea:

 

[bruceb58]

while I agree the 12 volt side is 48 watts, however what is the 110VAC side drawing. this is the side you need to power since your 12 volt side is dead.

My guess it is even less because the current 12V side has an inverter in it. All the 110VAC side does is run through a transformer down to 22VAC.

 

[bruceb58]

300sflyer, if you isolated the bad part section to the oscillator, when not fix the oscillator and happy boating again?

If you had a scope, a schematic and the skills to troubleshoot something like this then maybe.

 

[300sflyer]

If you had a scope, a schematic and the skills to troubleshoot something like this then maybe.

I don't have the skills or the equipment needed to replace electronic parts on the circuit board. I picked up a 700W inverter last night. I should have it running by the weekend.