Fridge's in your car or 4x4 or bus

howdrink · Senior Member

Fridge's in your car or 4x4 or bus

Yuglamron · Guru

Hi guys,agrre totally with your post.Too small wiring causes lots of problems with the fridges.
I would add a smart solenoid to the circuit though.They are available through Battery World and other outlets that do 4x4 stuff.Means you can use another battery which will be charged when driving and it automatically isolates your main cranking battery so it does not drain if your extra battery runs flat.

Not cheap at around $150 but cheaper than a tow or stuffed electronics if you use jump leads.

Easy to wire and don't forget to use 6mm or larger cable.

Helena · Guru

This is nothing to do with fridges in cars etc but as it is a fridgy thing though I would add it to this thread hope you don't mind when in Queensland last year couldn't drop the fridge control down to 3 as it would go out (it is a three way fridge) yet when we camped a couple of weeks ago in Deep Creek National Park we didn't have any problem with it could it be the weather in Queensland that could cause this problem Thanks Helena.

ken · Veteran Member

Thanks we have 2 fridges and we have been having trouble keeping the temp I was just starting to think it was the fridgees but both to go at same time I have just had the second battery installed to help the problem but couldnt figure it out so now I have another angle to look at.

Thanks
Ken & Cheryl

jimricho · Guru

One of the symptoms of wiring that's too light is that the compressor will be trying to start and will be cutting in and out every few seconds. Any terminations/connections in the system need to be secure and clean as this can be a cause of voltage drop. Apart from wiring that's too light, cig lighter plugs and sockets would be a major cause of fridge troubles. I consider these to quite unsuitable for use with car fridges, I've had problems with the "Hella" type plugs too, the Clipsal ones (similar to ordinary 240v power plugs and points but with 2 pins instead of 3) are the most reliable.

If trouble shooting a voltage drop problem, the measured voltage drop can appear ok but this can be misleading as compressor fridges momentarily draw significantly more amps when starting up.

Both Engel and Waeco sell wiring looms to overcome the problem of the car's wiring being too light.

-- Edited by jimricho on Sunday 1st of May 2011 06:53:44 PM

jimricho · Guru

Regarding 3 way fridges.... Running these from an auxiliary (house) battery is a lost cause due to the amount of current they draw. They should be wired to the main (starting) battery via a relay that disconnects the 12v when the engine is not running. This relay is in addition to the "smart" relay referred to above.

The gauge of the wiring is even more critical with these. I have a voltage booster installed in the Goldstream that recovers the voltage drop and supplies 13.8 volts to the fridge element.

-- Edited by jimricho on Sunday 1st of May 2011 07:08:43 PM

Helena · Guru

HI Jim, Yes have done that with ours Helena.

Turtle · Veteran Member

hey folks Im running 2 3ways direct from the main battery via 1 6mm cable and an anderson to the van no probs. can leave both connected for up to 2 hours and the Prado still strts ok,go gas or 240 overnight Turts

jimricho · Guru

Turtle wrote:
hey folks Im running 2 3ways direct from the main battery via 1 6mm cable and an anderson to the van no probs. can leave both connected for up to 2 hours and the Prado still strts ok,go gas or 240 overnight Turts

As the battery ages or in less than ideal conditions you may find that 2 hours is "stretching the friendship". 4WDs generally have more robust batteries (especially diesels). Most modern sedans/2wd wagons are fitted with batteries that have poor deep cycle performance.

The real trap is forgetting and staying longer at a lunch stop (or similar) than planned. I have a friend who did this and had to replace his battery and had his travel plans disrupted as a result. (I'm unaware of the age of the battery.)

An alternative to a simple control relay is a low voltage cut-out adjusted to ensure there is still sufficient charge to start the car. This would supply 12v to the fridge for a while when stopped.

There is also a gizmo called a "Fridge Switch" (click on underlined link) that can be wired into the caravan's fridge wiring that cuts the 12v to the fridge when it detects the van is not moving. I've not used one so I can't vouch for its effectiveness but I can't see why it wouldn't work ok. This may be a solution for those who don't wish to further modify the wiring in the vehicle.