Running 3 way fridge via inverter

[Lefty]

I only intended to run it via the inverter when on the move, essentially just replicating the way the normal 12v system works. I realise that there would be the inverter overhead but again, whilst on the move considered that covered.

All that said, I had discounted the option of a simple repair on the grounds of obsolescence but hairy dogs post prompted me to look and replacement elements are available on eBay for around £12.

The only rub then is that it would mean taking the fridge out and if I did that I could be sorely tempted to go down your route of fitting a domestic compressor fridge.[/QUO

I have an Electrolux RM270 fridge fitted to my van.

I suspect the 12v section is faulty (I will investigate more fully in due course) as it cools fine on mains hook up and on gas, but even if it is cold already does not stay cold when 12v whilst driving.

Looking at the specs and wiring diagram I see that 240v element is 105 watts and the 12v element is 100 watts. Also, the 240v element is controlled by a thermostat whereas the 12V element is on all the time the 12V is present (engine running).

It seems to me that a reasonable solution might be to, take the 12v supply to the fridge and use this via an inverter to feed the 240V fridge circuit. I realise that I would not then be able to use the fridge on mains hookup.

Any thoughts?

Light the gas up go off on adventures turn off when you get home, no fuss or forgetting to change over. The electric elements drag your battery down very quickly that why the engine has to be running on 12v.

 

[linkshouse]

Absolutely no reason at all not to do this while driving, assuming you have the inverter already. I've been doing it for years and it's actually better and cooler on 230v vs 12v.

Sorry, I hadn't spotted that this thread had been re-opened.

Thank you for your feedback on your own use of 230V.

I do have a small (300W) inverter in the van that is used for the telly and charging my laptop. So I could use that with a bit of extra wiring. Or I may shell out for a dedicated inverter as it shouldn't need to be pure sine wave for a resistive load like the fridge heater so shouldn't cost too much.

That all said when I got the chance to investigate further I found that although the relay was working fine and the light on the fridge switch was lighting when the engine was running there was a very dodgy connection from the switch to the element I've remade that and will check how the fridge performs on 12V next time we're out.

 

[linkshouse]

Just run it on gas all the time and save yourself all the hassles that are being suggested.

Whilst I have on the odd occasion forgotten to turn the gas off before setting out, I wouldn't be happy to do it on a routine basis. It would be very dangerous at e.g. a petrol station. In any event, I would never get the idea past SWMBO.

 

[MartinFa]

If you're thinking of running the fridge off an inverter whilst driving, is there a way you can connect the output of your inverter, via a 13A plug to 16A socket converter, and thence plug in to your ehu point? Of course, if your ehu connection is outside, that wouldn't work (ours is in the moho's garage so I can route a cable internally).

Otherwise - as, like myself, you're a retired electrician - you could open up your consumer unit and disconnect the incoming line from the ehu point. Then connect your inverter output to the consumer unit bus bars. All a pain in the backside, of course, and a fairly extreme measure, but it should work.

 

[linkshouse]

If you're thinking of running the fridge off an inverter whilst driving, is there a way you can connect the output of your inverter, via a 13A plug to 16A socket converter, and thence plug in to your ehu point? Of course, if your ehu connection is outside, that wouldn't work (ours is in the moho's garage so I can route a cable internally).

Otherwise - as, like myself, you're a retired electrician - you could open up your consumer unit and disconnect the incoming line from the ehu point. Then connect your inverter output to the consumer unit bus bars. All a pain in the backside, of course, and a fairly extreme measure, but it should work.

I had in mind to use a dedicated inverter and just take the existing 12V supply for the fridge to the inverter and then replace the fridge mains switch with a centre off double throw switch to feed the 240V element form either the EHU or the Inverter.

 

[hairydog]

I had in mind to use a dedicated inverter and just take the existing 12V supply for the fridge to the inverter and then replace the fridge mains switch with a centre off double throw switch to feed the 240V element form either the EHU or the Inverter.

If you are opening it up, why not fit a relay, which automatically switches the power to EHU when that's live? Easier, cheaper and neater than changing the switch.

 

[hairydog]

Whilst I have on the odd occasion forgotten to turn the gas off before setting out, I wouldn't be happy to do it on a routine basis. It would be very dangerous at e.g. a petrol station. In any event, I would never get the idea past SWMBO.

The danger at petrol stations is starter motors. Big fat sparks near the ground where petrol vapour collects. A fridge isn't going to be 2% of that risk.
I ran on gas all the time for a year or two until I got round to finding the fault (it was just a corroded fuse connection). No problems at all, no trail of blazing filling stations.