12v versus 120v fridge

[jack2]

Hi, Thanks for all your ideas and suggestions.

The answer lay at Puffer Parts today -

I was in there getting other stuff and saw a 12v fridge at £230. it had been faulty and was just back from the manufacturers. Too good to resist!

Thanks again for all your help

[WotEver]

Hi, Thanks for all your ideas and suggestions.

The answer lay at Puffer Parts today -

I was in there getting other stuff and saw a 12v fridge at £230. it had been faulty and was just back from the manufacturers. Too good to resist!

Thanks again for all your help

 

Ensure you feed it with big fat cables

[smileypete]

On the basis that your 600mm fridge is approx 20% bigger than our 500mm (and assuming it has an ice box like ours) our 1.4a @24v equates to 2.8a on 12v x 1.2 fridge size which with our PSW 94% efficient inverter works out at 3.5 amps (ish) compared to your 6.5amps!

 

So a PSW would be a big improvement?

 

Gibbo?

 

Well though I'm not Gibbo , I'd have thought there's some difference but not a huge amount; other factors will play a bigger part.

 

Best way to compare might be run a fridge through an electricity supply meter, then compare 240V landline to 240V MSW under the same working conditions.

 

MSW will generate some higher frequency 'harmonics' along with the 50Hz AC, which will lead to the compressor running a bit hotter and so less efficiently as it will still run at the same rpm.

 

Edit:

 

One thing that makes a big difference to efficiency is the temperature the black grid at the back gets up to.

 

If it gets quite hot, especially in summer then directly cooling at least part of it with computer fans will boost efficiency.

 

It might make the running current increase a bit, but the duty cycle will drop considerably.

 

The more efficient fridges use a bigger grid to get the same effect.

 

cheers,

Pete.

Edited October 16, 2009 by smileypete

[Keeping Up]

One thing that makes a big difference to efficiency is the temperature the black grid at the back gets up to.

 

If it gets quite hot, especially in summer then directly cooling at least part of it with computer fans will boost efficiency.

 

It might make the running current increase a bit, but the duty cycle will drop considerably.

I added a fan to mine this year. I cut a hole in the floor and screwed the fan over it, so it sucks cold air in from the bilge and blows it at the grill. The fridge has a connection for a fan which ensures the fan only runs wjen the compressor is running; I also used an old room thermostat so the fan also only runs when the temperature next to the grill requires it.

 

The fan runs a lot in hot weather or when the oven is on (it's next to the fridge), and not at all on cooler days. The fridge definitely runs a lot less than it used to on hot days