Volvo 940 and fridge

[Metallo]

Hi there,

I have a Volvo 940 SW and I want to add a 12V Compressor-type Refrigerator.

The specs of the fridge are the following:

Rated Power Input: 60W
Rated Current: AC 1.2A - 0.5A - DC 5.0A/2.5A

I want to add a separate cigarette lighter plug on the back of the car, and I am looking for:

1) Any advice on where I could install the plug on the side of the trunk. I was wondering if any of the 940/960 series ever came with a second 12V plug, if so where was it placed by Volvo?
2) Keeping in mind the above specs, I am planning to run a 12V wire directly from the battery to the back of the car. Which wire gauge would you recommend?
3) Which value would be good as a fuse on that circuit?

The fridge will only be ON while I am driving the car on the highway.
As a result, want the new 12V plug to be OFF when I turn the engine OFF, like the existing 12Vplug.
This will make sure I never drain my battery

Any other advice is very welcome!

Thank you,
Alex

[RickHaleParker]

You need to figure out the peak current and plan the wire size around the peak current.

Look for a marking LRA ( Locked Rotor Amp ) on the product plate or in the spec sheet. LRA is an average value. Start with LRA then add some more for a safety margin. Then some more for the long run.

LRA in this example is 5A @ 115V. It would be about ten time that at 12V. 115V/12V * 5A = 48A.

[Metallo]

It is rare to find the LRA on the specs, all the data they share on their site, is the one I posted above.
It is a small 21Quart(20Liter) fridge, with a compressor, I should be more than safe with a 10 AWG with a 15A fuse.
According to their specs, it should be max 5.0A.

Alex

[RickHaleParker]

Take a clue from the refrigerator's fuse size and type. If it is 5A fast blow figure 5A max. If it is 5A slow blow. The startup current is more then 5A.

The small portable refrigerators take a long time to cool down. I use to pre-cool them with a AC to DC power supply before I took off on a trip. Every time they warm up and then you got to go through the long cool down again.

There is a option to work around this . Go to a junkyard and get the Battery Cables from a Volvo with a rear mounted battery. Install the cables, a House Battery in the rear and a battery isolator. Run the refrigerator off the House battery. Be sure to vent the house battery to atmosphere if is a FLA ( Flooded Lead Acid ) or us a AGM ( Absorbent Glass Mat ) battery which does not need to be vented to atmosphere. With the large battery cables you need not work about being too small and you can charge fast the House battery faster.

The second battery will charge when the car is running if you drive long enough. When you turn off the car ,the battery isolator with disconnect the house battery from the starter battery. You need not worry about the refrigerator draining the starter battery. The House battery will provide energy to keep the refrigerator cool for some time.

If you are just planning to keep your soda cold on the 500 miles trip to mom's house this is not for you. An AC to DC power supply and pre-cool will do.

[Metallo]

It sounds like in your case you are referring to a thermoelectric cooler.
What I want to purchase is a compressor-type refrigerator, its reviews say it ranges between :-4℉～50℉ and it can go from 68F to 32F in 20 min.
When I travel, I do long trips, and this one will be particularly long, approx 6000 miles entirely on highway, I am not planning to keep the fridge operating while the engine is off. In the hotel, I can plug it in the AC.
According to reviews, it never reaches 5A.

Alex

[RickHaleParker]

In the hotel, I can plug it in the AC.

Ah man ... you will have nothing to contribute to camping in a Volvo thread.


60W / 12V = 5A make me a little suspicious of the 5A peak current claim.

Size the fuse to the wire size and keep the 5A fuse of the refrigerator. Wire fuse should be on the ( + ) battery end.

If you use a chassis ground you only need to count the wire from the battery to the refrigerator.