Fridge Power Draw

Vince · Senior Member

Fridge Power Draw

Olley46 · Guru

Hi Vince

You can also fit a motion switch to your fridge,when there isn't any movement of towing the van the fridge will switch off automaticly,when you start towing the fridge will switch on again,very simple to fit.

Lance C

Vince · Senior Member

Yes Lance I had a look at that idea and decided that putting a relay and a dash light connected for function - IE on / off

I can also see if power is getting thru while ignition is on if not look for a blown fuse or other problem.

I'll test it out on our trip to Wari with a 1 night stop over at Mittagong starting Thursday

Spydermann · Senior Member

Some fridges turn off if they cannot get at least 12V so they don't drain the battery when stopped. Check the fine print in the fridge manual.

03_Troopy · Guru

Your ignition operated relay is a very common way to do it, and works well.

Olley46 · Guru

I have both my fridges van and the Bushman in the 4wd running through two toggle switch,s on the dash, so I can turn them on and off at random, I have two monitors in both fridge,s giving me a read out of tempature , I know if the temp drops dramaticly I have a problem some where.

Lance C

dogbox · Guru

Spydermann wrote:

Some fridges turn off if they cannot get at least 12V so they don't drain the battery when stopped. Check the fine print in the fridge manual.

most of the fridges that have low voltage cut out are set up to protect the fridge not the battery they will draw power till it is to low to run them then cut out usually not enough left to start vehicle

PeterD · Guru

Spydermann wrote:
Some fridges turn off if they cannot get at least 12V so they don't drain the battery when stopped. Check the fine print in the fridge manual.

Those fridges are the AES (automatic energy select) models. Look for that in the fridges handbook. The AES fridges have a wire from the tugs ignition circuit so they only operate on 12 V when the motor is running (if they are wired correctly, many are not.) If you have the gas bottle turned on the AES fridges will light the gas 20 minutes after you stop the motor. None of the other fridges have any protection.

-- Edited by PeterD on Wednesday 30th of September 2015 11:45:59 PM

PeterD · Guru

03_Troopy wrote:
Your ignition operated relay is a very common way to do it, and works well.

This is the way that Dometic recommend that you wire up your tug.

Dometic Fridge 12 V Wiring 2.PNG

Vince · Senior Member

Thank heavens for this forum. Turned the van fridge on and no go. Tried 12v and no go couldn't use gas because van is parked on a slope. found by searching forum fridge won't work on sloped ground. parked it level and all 3 ways work...phew! information here is GOLD.

Aus-Kiwi · Guru

Some 3 way only work on stand by on 12v .. The thermostat doesn't work on 12V..

katenal · Member

Hi,
My understanding is that with 3-ways or the larger units like our 184l the 12 volt option is only to "maintain" fridge temperature while travelling. Our Manual says to switch to gas or 240 v when parked. Guess if you stopped to check out something of interest for half an hour you wouldn't bother but if it was for a few hours and given while the van was stationary things inside would heat up I would consider running the fridge on gas if not to save some battery at least keep the beer cold, and the food of course.

elliemike · Guru

Vince wrote:
Thank heavens for this forum. Turned the van fridge on and no go. Tried 12v and no go couldn't use gas because van is parked on a slope. found by searching forum fridge won't work on sloped ground. parked it level and all 3 ways work...phew! information here is GOLD.

The Absorption type (3 way ) fridge needs to be Level at all times when in use.

That is whether on 240v, 12v, or gas heating the the liquid in the system. It need to be level to allow the liquid to Thermo Syphon (flow) around the pipework.

I use a Fridge Switch in mine. Think it cost about $40 when I fitted it about 5 years ago. Never had a problem with it always works well. Easy to fit.

PeterD · Guru

elliemike wrote:
I use a Fridge Switch in mine. Think it cost about $40 when I fitted it about 5 years ago. Never had a problem with it always works well. Easy to fit.

Currently the Fridge Switch coats $66 . Why not user the protection that Dometic specify? An ignition switched relay costs less than $10 and the installation costs are around the same. An added advantage is if you are getting an auto elec to install it you don't have to drag your van around to him.

PeterD · Guru

Aus-Kiwi wrote:
Some 3 way only work on stand by on 12v .. The thermostat doesn't work on 12V..

A lot of the large fridges do have the 12 V element controlled by the thermostat. The reason that people think that the 12 V operation is inefficient is the RS wiring that auto electricians and van manufacturers install. Those who have rewired their vans and tugs with the proper size wire have good results. I have even seen some travellers report that the fridge temperature has come down to near good operation temperature after they pick their vans up from storage and they proceed to their first camping spot. Don't whine about your fridges performance, do something about it.