Caravan and car power

When leaving my car connected to new Discovery van on the Spirit trip, found car battery was flat overnight. Have an anderson plug fitted wired from car battery to van. What caused this to happen? Should I ensure that battery switch is on?
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Reply By: DBN05 (tas) - Tuesday, Jul 29, 2014 at 15:56

Tuesday, Jul 29, 2014 at 15:56
Hi bii w7
did you leave the fridge on 12v that will drain battery overnight. easily done (have done before on the spirit )

my two cents for what its worth

Harvey (dbn05 tas ))
I NEVER get lost, but don't i see a lot of NEW places.

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Reply By: Allan B (Member, SunCoast) - Tuesday, Jul 29, 2014 at 16:12

Tuesday, Jul 29, 2014 at 16:12
Hi Bill, It sounds as though your car is not fitted with a Battery Isolator to separate your car battery from the van when the motor is stopped. Even if you left the fridge on in the van it should not affect your car cranking battery, but can discharge the auxiliary battery in the van.

Take a look at Auxiliary Battery Systems - Blog, particularly Diagram 3 for details of a wiring diagram suitable for your situation.

What do you refer to by ...... "Should I ensure that battery switch is on?"
Cheers
Allan

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Follow Up By: bill w7 - Tuesday, Jul 29, 2014 at 18:09

Tuesday, Jul 29, 2014 at 18:09
Thanks all - I mean the battery isolation switch - should I have left it on to ensure the slave battery was used and not the car battery? I am not aware of any isolation switch between the car and the van - the anderson plug is not connected via the accessories switch. If I was to turn the fridge off completely then all would have defrosted.
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Follow Up By: Nomadic Navara - Wednesday, Jul 30, 2014 at 20:58

Wednesday, Jul 30, 2014 at 20:58
Quote "If I was to turn the fridge off completely then all would have defrosted."

If you cook your fridge up properly for some time after you last open the fridge before you embark your fridge should be OK. Best do that on a night crossing although it is still fairly cool in the hold on day time crossings.

We did a night time crossing in February. We turned the gas up a bit in the afternoon. Half an hour after eating after having our evening meal we headed for the ferry and the fridge was not opened until the quarantine inspection in Tasmania. We then drove to Burnie and did some shopping. When we opened the fridge again to stow our food the freezer contents were somewhat mushy. We then booked into the park at Somerset and refroze the fridge.

It's OK to refreeze food if it has not been thawed out of a fridge and there are still some ice crystal in it. The instruction to not refreeze frozen food is not the complete instruction. The only food you should not refreeze is food that has been thawed out of the fridge. If your fridge has been warmed somewhat you should reduce the keeping time of your food, but who keeps food very long in a caravan fridge, you don't have the capacity to keep much. We also arrange so we do not have food like chicken that is a little touchy regarding not being kept properly during periods when we know the fridge will be warmed a bit.

PeterD
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Reply By: HKB Electronics - Tuesday, Jul 29, 2014 at 16:27

Tuesday, Jul 29, 2014 at 16:27
Does your van have a three way fridge, if so then the fridge should be wired
directly to the cranking battery by an automatic isolator such as a fridge switch etc. A three way fridge will draw around 15 amps and flatten any battery in a short time.

Also as above, your vehicle should also have an isolator between the cranking battery
and any auxiliary batteries to protect it from accidental discharge.

Leigh

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Reply By: Erad - Wednesday, Jul 30, 2014 at 09:12

Wednesday, Jul 30, 2014 at 09:12
Bill W:
Your caravan fridge will flatten your battery very quickly if the engine is not running and you leave the fridge on 12 Volts. The boat people have massive battery packs to get people moving - as you no doubt found out.

Other people have replied pushing the fridge switch, but maybe this would not work in this case. The fridge switch relies on sensing motion to allow current to the fridge. Possibly the movement and vibration of the ferry would be enough to keep the fridge on and still batten your flattery. Next time, I would be inclined to unplug the caravan completely.
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Reply By: Member - Craig F (WA) - Wednesday, Jul 30, 2014 at 18:34

Wednesday, Jul 30, 2014 at 18:34
Has the van got electric brakes?
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Reply By: Janos K - Wednesday, Aug 06, 2014 at 17:58

Wednesday, Aug 06, 2014 at 17:58
You can always use a DC breaker in between the two batteries, Acts as a protection device but can also isolate the secondary battery when stationary.
http://www.wallcann.com.au/dc-circuit-breaker-surface-mount-8zed.html

OR as a back up a jumpstarter just in case ???
http://www.wallcann.com.au/categories/jumpstarters.html
AnswerID: 537257

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