Fridge Voltage

[KBerg Rig]

Hello All....another 12v fridge question.......hopefully someone can confirm the voltages I'm seeing with fridge operating on 12v are OK/standard.

My Anderson plug on the tug (patrol) is always live (not my choice just how it came from previous owner) it puts out 12.7v engine not running & 13.80v engine running. These figures look correct to me.

I pulled the bottom vent cover off and at the fridge (not turned on to 12v) engine not running I get 12.6v and engine running I get 13.75v.

However when I turn the fridge on to 12v the voltage (engine running) drops to 11.4v.

Can anyone confirm if 11.4v is ok to run the fridge? Is 2.4v drop when turned on acceptable, correct or normal?

The cable running to the Anderson plug on the car doesn't look anything special i.e very thick and the van wiring is standard jayco (apart from fridge power moved to Anderson plug from 12pin plug)

If I replace this wiring with something more substantial and make the run through the van more direct can I expect less voltage drop and better performance?

I'm sure I'm no Robinson Curuso with this issue....

Much thanks, Matt.

 

[jvp]

Thicker wiring to reduce voltage drop will improve performance.
The readings you got are not uncommon.
The 12V operation is not through a thermostat & only helps to maintain fridge temperature while driving. This may be for a short time only.
Most work good enough.
jvp

 

[millers]

Matt,
Did you happen to measure the battery voltage at the car to determine the actual voltage drop. From your measurments you are assuming that the no load voltages are being maintained at the battery under load. This may not be the case. Measure the voltage at the battery and then measure the voltage across the fridge to determine the voltage drop. If you want to get technical and have a long enough test wire measure the voltage from battery + to fridge + and from fridge - to battery -. This will give you the voltage drop on positive and negative cable runs.

Would not be good to contribute all to cable loss, when it may be the battery dropping voltage under load.

I hope I have read your post correctly.

Cheers Steve

 

[Burnsy]

Matt I'd be pretty happy with that! I only get 9v to my fridge when switched to 12v but that's only through 6mm twin cable. I will probably get around to running it through my Anderson which uses 6b&s but in saying that items still frozen after 5hrs on the road!

Cheers.

 

[Hubble80]

You are only losing 1V when the fridge is running. Would not be concerned. However to stop you accidentally draining your battery I would put something between the Anderson plug and you battery. This could be a VSR like a RedArc SBi12 or similar, or even just a circuit breaker. You could even use both if you wanted.

When I was last in Brisbane, I saw a decked out Patrol and three little so and so's with a paperclip watching the sparks they were making at the plug!!!!