Car <span class="highlight">wiring</span> and van <span class="highlight">wiring</span> for fridges

Submitted: Thursday, Dec 01, 2011 at 11:09

ThreadID: 90395 Views:5168 Replies:5 FollowUps:9

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Battery Power

In this article we explain why you might need an additional power source independent of the starting battery installed into your vehicle and we look in detail at types of batteries,

Wak01

Hi all
My first go at this so please be gentle.
I have a Triton dual cab (2008) and a jayco finch outback (2004) and i am trying to wire up the car to run the 3 way fridge in the van as well as
an engel 2 way in the back of the car when we are travelling. We are off on a 7 week trip soon, and as we may want to leave the car and van to possibly check out a track or have lunch etc we need to be able to power both without having to popup the van lid. Basically my intention is to power the compressor fridge (3amps) in the back of the car via the car battery and use the van battery (100ah gel) to power the van fridge (12.5amps). If we are gone too long a low voltage drop out installed in the van will protect the van battery until we get to van park where the battery can be recharged by a 3 stage charger.Feedback and wiring diagrams would be appreciated.

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Reply By: ChrisK - Thursday, Dec 01, 2011 at 11:40

Thursday, Dec 01, 2011 at 11:40

Have a look at this site for some really good info...
Dual battery systems
Hope this is useful to you.

AnswerID: 471430

Reply By: landseka - Thursday, Dec 01, 2011 at 11:58

Thursday, Dec 01, 2011 at 11:58

I have an Andersen plug at the back of my MN Triton which feeds directly to my van fridge. I have a 12v socket (T shaped) in the tub to run my Engel.

The van battery is charged by 2 roof mounted solar panels or, if insufficient sunshine I top it by generator or park power (rarely needed).

When you are away from your camper I would strongly suggest running your 3way on gas, your battery will NOT last long running the fridge.

Cheers Neil

AnswerID: 471433

Follow Up By: Wak01 - Thursday, Dec 01, 2011 at 12:50

Thursday, Dec 01, 2011 at 12:50

Thanks Landseka but the Jayco manual advises not running the fridge on gas when the lid is down due to the vent on top of the fridge bench not having adequate ventilation and subsequent fire risk. That is why i was looking at the battery with a low voltage dropout. I should still get 3-4 hours of use before dropping out (at about 50% battery capacity i expect).

FollowupID: 746075

Follow Up By: Lucko - Thursday, Dec 01, 2011 at 14:49

Thursday, Dec 01, 2011 at 14:49

I strongly support Landseka's suggestion about running on gas when the van is left, what's the drama in popping the top?
You deep cycle battery will not last very long - not just before it goes flat, but more importantly before it goes bye-bye (at least $300 for a half decent 100AH battery when last I looked). These batteries have only so many charge/discharge cycles in them. The more severe the discharge the fewer the number of cycles available. That's my experience in any case. Cheers

Mark

FollowupID: 746087

Follow Up By: Wak01 - Thursday, Dec 01, 2011 at 14:57

Thursday, Dec 01, 2011 at 14:57

Thanks Lucko
The problem with popping the lid is the van is no longer secure unless i set it all up and that seems a fair bit of hassle just to stop for a while then continue on.

FollowupID: 746088

Reply By: Wak01 - Thursday, Dec 01, 2011 at 12:46

Thursday, Dec 01, 2011 at 12:46

Thanks Chrisk but i was hoping to get away with out installing a dual battery in the car. If i wire it up with a relay so that there is no power when the car is not running that should protect my battery from going flat.

AnswerID: 471437

Follow Up By: Bushranger1 - Thursday, Dec 01, 2011 at 16:10

Thursday, Dec 01, 2011 at 16:10

Yep the relay is a good idea but how will you supply power to the Engel fridge when stopped overnight when you are not connected to 240V power?

2 options as I see it.

Second deep cycle battery installed in the car for the Engel OR run a wire from the van to the car for the Engel. Of course if the van fridge has flattened the van battery then the 2nd option will not work.

One thing I discovered on my 2 year trip is you need to have a rough idea of the type of camping you will do and set up the system to suit.
For example some people like to plot in one place for days with no power available so clearly alternator charging only is no good. But this system suits me because I dont stay in one place for long & never have access to 240v power.

So which setup is best is dependant on your camping style and access to 240v power.
Hope this helps you a bit.

Cheers
Stu

FollowupID: 746097

Follow Up By: ChrisE - Thursday, Dec 01, 2011 at 16:15

Thursday, Dec 01, 2011 at 16:15

Check the diagram on that website. It shows a car and van setup without a car dual battery. Use the redarc as suggested and it will automatically cut power when the your cars battery level drops a bit, however this will drop out quite quickly, leaving you with no power to your fridge in the car (the van will look after itself as it has its own protection from your post). Best option really is a dual battery/battery back which could be mounted near the fridge if you don't have room under the hood.

FollowupID: 746099

Follow Up By: Wak01 - Thursday, Dec 01, 2011 at 16:19

Thursday, Dec 01, 2011 at 16:19

Thanks Stu
I really appreciate all this feed back this site is great. We will only need the compressor fridge in the car to be powered in transit as we dont envisage being away from 240v at night time.

FollowupID: 746100

Follow Up By: Wak01 - Thursday, Dec 01, 2011 at 16:36

Thursday, Dec 01, 2011 at 16:36

Thanks ChrisE/K
Yeh i see what you mean. Perhaps i could use the van battery as my Auxillary battery to power the Engel (as Stu suggested) if i was at a site with no 240v (and i hadn't used the battery during the day to power the van fridge). The van fridge would be on gas then at night and would have been powered via the car battery during transit.

FollowupID: 746104

Reply By: Bushranger1 - Thursday, Dec 01, 2011 at 16:57

Thursday, Dec 01, 2011 at 16:57

If your going to have 240v power available every night then I would use the car battery to run the Engel (it will run off alternator when driving) and van battery to run the 3 way during the day and connect BOTH fridges to the 240v each night. Also charge the van Battery at the same time at night.

You will not flatten your car battery with the Engel running off it for a few hrs in the middle of the day when stationary. If your worried then turn the Engel off during the miday break. It will stay pretty cool for a couple of hrs with no power.

There is no use paying for relays & wiring if you don't need too. More money for holidays!

If your camping style changes then just re-asses your power needs & wire it up to suit.

Cheers
Stu

AnswerID: 471456

Follow Up By: Not so grey nomad - Thursday, Dec 01, 2011 at 20:04

Thursday, Dec 01, 2011 at 20:04

Hi there
we also have a triton dual cab, that we towed a goldstream storm with (before it got stolen,....whole other story) We had a 12 plug in the back tray for the evacool fridge and an anderson plug to charge the camper battery as we drove. We often stopped for a few hours at a time and never bothered to run the fridge on gas, it was closed up and managed for that period of time.Our auto leccy wired a cutoff switch into it somehow( dont ask me the ins and outs i am a girl lol) to when the car ignition was turned off it cut the power to the van, it stops the car battery being drained by the fridge. If we had no power out in the bush we always ran the fridge on gas,the fridge uses way to much power to try running it froom you van battery, would drain it in a matter of hours.
hope this helps

FollowupID: 746119

Follow Up By: Bushranger1 - Thursday, Dec 01, 2011 at 20:41

Thursday, Dec 01, 2011 at 20:41

I just realised that I meant to say run the van fridge off the van battery over your lunch break & have it charge off the alternator while you drive.
Then when you get to the 240v for the night charge the van batt up to full capacity.

FollowupID: 746125

Reply By: LeighW - Friday, Dec 02, 2011 at 08:37

Friday, Dec 02, 2011 at 08:37

You will most likely have problems trying to charge the van battery off the car if the fridge is running unless you have run massive cables for the power. A 3 way has you wrote will draw 12.5A continuously and make it difficult to charge the battery using normal van wiring as supplied by the manufacturer.

I would suggest you run the car fridge of the car battery.

Install a movement activated switch for the van fridge, these are not expensive and will turn of the power to the van fridge when the car is not moving.

Place a ice pack or bottle of water in the van fridge freezer or bettre still keep the van freezer full. Assuming you will run the van fridge on gas or 240 over night the freezer will stay frozen for a few hours without power during the day as long as your not opening and closing the day. Just set the thermostate a little higher whilst moving dailly

Cheers
LeighW

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AnswerID: 471523