Inverters ,12v supply to 240 appliance.

chrisnchris · Senior Member

Inverters ,12v supply to 240 appliance.

Peter_n_Margaret · Guru

Depends on the power consumption of the fridge and the size of the cables to and from the anderson plug.
Need that information.

Cheers,
Peter

justcruisin01 · Guru

chrisnchris wrote:
Hi,
i have a 240v/gas fridge. It seems OK on gas but i would like to run it while travelling,using my Anderson plug to supply 12vthrough an Inverter to the 240v system.
Will this work? I imagine it will not be very efficient but would it still be better than nothing?,
Cheers

You will find that the 12volt power consumpion will be very high, would need very HD cables etc to do this from the tug.

I have a 600watt pure sine inverter mounted in the van, I connected the fridge to it just the check the12volt power usage & it was drawing 18amps.

Maybe run it on the 12volt while travelling, thats what I do.

JC

jimricho · Guru

chrisnchris wrote:
Hi,
i have a 240v/gas fridge. It seems OK on gas but i would like to run it while travelling,using my Anderson plug to supply 12vthrough an Inverter to the 240v system.
Will this work? I imagine it will not be very efficient but would it still be better than nothing?,
Cheers

Doesn't it have provision to run directly from the car's 12volt system via the Anderson plug?

oldboar · Senior Member

The way I read the original post the fridge is only a 2 way. If that is the case, running via an inverter seems the only real option unless they take the risk of running it on gas while travelling (definitely not recommended)

Darrell

jimricho · Guru

oldboar wrote:
The way I read the original post the fridge is only a 2 way. If that is the case, running via an inverter seems the only real option unless they take the risk of running it on gas while travelling (definitely not recommended)

Darrell

That's how I read it too but I've not ever come across a gas type fridge in a caravan/RV that was not a 3way. Maybe they do exist.

chrisnchris · Senior Member

Cheers and thanks for the replies. The fridge is an Electrolux two way fitted originally in a 1983 Millard van.

jimricho · Guru

Thanks Chris for clarifying that. Obviously your only option is to use the inverter if you wish to run the fridge when travelling.

Absorption fridges (that's techie-speak for fridges that run on gas) are not very efficient anyway. The cable needs to be heavy gauge to reduce the voltage drop as much as possible. The 12v power for the inverter will need to come from the vehicle's main (ie starting) battery, not an auxiliary battery or the van's "house" battery as it will soon flatten these.

If you don't already have one I'd recommend installing a relay in the circuit from the car battery to the Anderson Plug to automatically disconnect the 12v to the plug when the vehicle's engine is not running. The best option is a Redarc "smart charge" or similar unit that's primarily intended for dual battery systems but will work well here. Using one of these instead of a "common or garden variety" relay ensures that the Anderson Plug is not connected until the main battery has been recharged following a start.

A "modified sine wave" inverter would be ok for this job but if you're buying an inverter I'd suggest a "pure sine wave" as you may wish to use it for other duties where using an modified SW is not advisable.

Jim

PS: One thing to keep in mind is that 240v is just as dangerous when coming from an inverter as it is when coming off the mains.

jimricho · Guru

Former next door neighbours of mine (sadly both now deceased) used to do as johnno02 does and found it worked ok for them too.

-- Edited by jimricho on Monday 31st of December 2012 05:21:19 AM

johnno02 · Veteran Member

Chris,

We had a similar setup in our Van,and used to freeze some Techni-Ice sheets,or frozen bottles full of water,

when travelling,and put them in the fridge with the cold food/drinks etc,when travelling during the day

worked ok for us,on reasonably short runs,several hours or so,between stops.

John

chrisnchris · Senior Member

Many thanks for all the info/advice.It seems that my situation is not as common as I thought.I will try the inverter ,keeping in mind the cautions you have offered. Wait with bated breath and I will advise of my results in the near future.

deadlyprincess · Veteran Member

I seem to remember reading about a 12v battery charger that is placed in the van, that works on the step up process, only requiring light gauge wire to unit and heavy after. could be a posibility before inverter.

Dougwe · Chief one feather

Hi Chris,

I am just about to start a 12V re-wire of my Avan Camper in the next couple of days.

I am running 8mm wire from A frame direct to battery then another wire back to my 3 way fridge. I will have a portable 120W Solar Panel to charge the Camper Battery OR the car will do it through the Anderson Plug.

I am thinking of fixing the Solar Panel to the racks on top of my Prado, locked as well, I don't use the racks and don't see a need in the near future. I do have a storage problem of the panel as it is has ended up a bit bigger than it looked on the wall in the shop. By having the panel on the top of the car my thought now is, maybe charge the Camper battery by Solar as driving along instead of the car alternator doing all the work, that way I can stop and the panel will keep charging with no risk of the Prado battery going flat. It will solve my storage problem as well. I can't see why this wouldn't work but stand corrected of course.

Chris, maybe you could think of a similar set up to keep your battery charging while using your inverter. (reason for my comment in your thread)

There are more knowledgeable people above and on this forum than me so they may correct me and send you off in a completely different direction. I will keep an eye on this thread as well for my reference.

Good luck with your project, and,

oldboar · Senior Member

Merely a simple little matter of having a pilot flame (or more) running in close proximity to the bowser whenever the vehicle needs refuelling. There haven't been a huge number of cases where the fumes have ignited but I certainly don't want to be within cooee of when they do. The insurance claim would have as much future as a snowball in hell as well. Do you smoke while refuelling as well - probably safer as there's no naked flame.

Darrell & Sandra

-- Edited by oldboar on Monday 31st of December 2012 06:14:23 PM

-- Edited by oldboar on Monday 31st of December 2012 06:15:26 PM

allinone · Senior Member

oldboar wrote:
The way I read the original post the fridge is only a 2 way. If that is the case, running via an inverter seems the only real option unless they take the risk of running it on gas while travelling (definitely not recommended)

Darrell

Hi oldboar why the risk of running on gas while travelling? I find it works better than the 12v, as on 12v th fidge seems to get hotter.

Thanks...

Peter_n_Margaret · Guru

It is illegal to go into a servo with a fridge running on gas.
End of storey.

Cheers,
Peter

jimricho · Guru

deadlyprincess wrote:
I seem to remember reading about a 12v battery charger that is placed in the van, that works on the step up process, only requiring light gauge wire to unit and heavy after. could be a posibility before inverter.

!2v to !2v battery chargers will operate most reliably when steps are taken to avoid excessive voltage drop between the source battery and the charger's input. The same applies to voltage boosters and inverters. The lower the input voltage the more current they draw to make up the shortfall in voltage. This additional current worsens the voltage drop and further increases the current drawn. These devices are not simple static resistive loads and do not behave like them.

I have a 13.8v voltage booster fitted to my rig to charge my van battery when on the move should I need to and found I needed to install the dual battery type relay to ensure stable operation, the reason I recommended it in my earlier post. It also prevents the main battery from discharging if some seriously stupid person leaves the ignition on without the engine running (um...um...guilty as charged Your Honour! disbelief confuse )

To sum up: go with the heavy gauge wire. Dougwe's choice of 8mm²(or 8 gauge) is a good one and would be appropriate here.

Jim

(PS: before someone tells me that 13.8 volts will not fully charge a battery I point out that this is not my primary means of charging the van battery and is only used very occasionally.)