Site Search
Print Page Setup Profile Login
Section Image

New Prado - Power to Van only with ignition on

Submitted: Sunday, Apr 01, 2007 at 16:26

Member - Peter R (QLD)

I am planning for wiring of new Prado so that power to van is only transmitted when ignition is switched on. This is mainly because of the drain on battery from fridge in van.
What are the alternatives to arrange this.
Having said that I will also have an Anderson plug on Prado/van for charging of van battery during travel
Is it possible that whilst power to van is not provided with ignition switch off to provide power to fridge through van battery.

In old vehicle I got sick of pulling plug out at fuel stops etc, but wanted to make sure grog etc was cold in fridge van.

Thanks

Pedro

Advertisement
ThreadID: 43881 Replies: 5
Views: 585 FollowUps: 13
This Thread has been Archived
Thread Summary
Thread Watch Back To Forum Alert Moderator FAQ
AnswerID: 231019   Submitted: Sunday, Apr 01, 2007 at 16:34

Member - Davoe (Nullagine) replied:

dunno if it is of any use but I bought a camper van that had the fridge running from the battery to the fridge via a relay. the activation wire for the relay was atached to the power in wire to the coil so when you pulled up the fridge turned off
you dont need to leave perth to go bush
Click Image to Enlarge
You dont need to leave Perth to go bush
Reply 1 of 5
AnswerID: 231020   Submitted: Sunday, Apr 01, 2007 at 16:41

Richard Kovac replied:

Hi Peter

Smarter people will be along shortly.. LOL
but till then get one of these wired in www.sidewinder.com.au/page83.html

that way your main car (crank) battery will always be fully charged and the van battery will only be connected to the car battery when the car battery is over a certain voltage...

Regards

Richard
Camped under Mt Leisler
Click Image to Enlarge
Still Getting There
Reply 2 of 5
FollowupID: 491921   Submitted: Sunday, Apr 01, 2007 at 17:39

Member - Peter R (QLD) posted:

Richard,
Thanks for that.
I will have a Redarc connected between cranking battery and auxiliary battery in car and this then goes through to back of car to an Anderson plug.
In turn the Anderson plug on van which is wired to van battery receives a charge while travelling when cranking battery reaches a certain voltage.
If I leave the 7 pin plug in with ignition off this would currently run the fridge off cranking battery , and in turn would drain it.
Don't know if the van battery through the Anderson plug picks up that cranking battery but if it does that may solve the problem providing van battery has sufficient charge.
Auxiliary battery is for running my Waeco in cargo area.
With 3 batteries there must be some way to keep the van fridge powered with the ignition off but with cranking battery always at sufficient charge to start car.
Perhaps wiring to fridge from van battery, linked to auxilliary battery in need may be the way to look at it.

Davoe,thanks for that suggestion too , will put it into the mix of ways to do it.

Pedro
FollowUp 1 of 1
AnswerID: 231027   Submitted: Sunday, Apr 01, 2007 at 17:21

disco1942 replied:

There is a thing called a fridge switch (or similar) that detects if the van is moving or not. If no motion is detected the fridge is switched off 10 minutes after you stop - also switches back on when you start moving. The big problem is in this 10 minutes you discharge the battery 5 A/H of current - every time you stop for a break if you have your fridge connected to your van battery.

The better way is to use separate cables for battery charging and the fridge. Have your Prado wired with a 12 pin socket. The 5 large pins will be sufficient to supply the fridge. Also ask that the fridge cable is routed through a relay that is energised when the ignition switch is in the run position. This will also mean changing the van plug - but not other trailers if you are using a flat 7 pin system (the 7 pin plugs mate with a 12 pin socket.)

If you want the fridge to work efficiently (assuming 3 way - you did not specify) you will need cable 6 squ mm in cross section - not 6 mm auto cable (which is lucky if it is 4 squ mm.) You will probably have to rewire the van as well - lots of manufacturers use wire that is too small for the job. If the fridge is at the back of a long van you may need heavier cable - the longer the distance the thicker the wire needed. Also these sizes assume you are using a chassis earth - if you are using a dedicated earth return then you have to double the size of the wiring.

PeterD
Reply 3 of 5
FollowupID: 491928   Submitted: Sunday, Apr 01, 2007 at 18:04

Member - Peter R (QLD) posted:

Peter D.,
Thanks.
Did you read my follow up to Richard Kovac which was posted after your reply.
I think I covered all points re the set up except that it is to a 3 way fridge Dominico.

The cable from anderson plug on van is heavy duty 6 B & S .
Cable from auxiliary to Anderson plug on car will also be 6 B&S.

Presently the van battery is charged via this separate anderson plug while the fridge is powered through the 7 pin plug.

Do all of your earlier comments still apply with this additional info.
Sorry I am a slow learner.

Pedro
FollowUp 1 of 7
FollowupID: 491938   Submitted: Sunday, Apr 01, 2007 at 18:27

disco1942 posted:

Forget the first paragraph - you are using my second suggestion. Just take note of my suggestion of using a van supply plug and socket with large pins and use heavy wire for the fridge. I once used the 7 pin flat units for my van - that was until I rewired my van with heavy enough cable and the fridge pin welded itself into the socket. The short answer is the second & third paragraphs still apply.

PeterD
FollowUp 2 of 7
FollowupID: 491946   Submitted: Sunday, Apr 01, 2007 at 18:59

Member - Peter R (QLD) posted:

PeterD,
Thanks again.
With the knowledge that I will have an Anderson plug from vehicle (running from auxiliary battery) which attaches to an Anderson plug on van both with heavy duty wire, do I still need heavy duty wire from ignition to a 12 pin plug which would power fridge and van accessories?
And would I need to change the wiring on van to heavy duty with 12 pin unit?
Or could I piggy back off the heavy duty wire on van (through existing Anderson Plug), which runs behind van fridge to the nearby van battery ?
The relay that is energised only when iginition is in run position sounds the go in the overall mix.
Lunchbucket has suggested this method too I think.
Wingbang, I will have a Redarc fitted and it will be between the cranking and the auxiliary battery .
Also intend to have a momentary Rocker Switch fitted in case cranking battery fails , and I can use auxiliary to start.
Peter
FollowUp 3 of 7
FollowupID: 491974   Submitted: Sunday, Apr 01, 2007 at 20:41

disco1942 posted:

Let me make it a little clearer. I recommend a completely separate cable for the fridge. You seem to have the battery charge sorted out to your satisfaction. The cable to the fridge (and through a heavy contact in the trailer plug) will go from the vehicles battery and charging circuitry to the fridge so as to obtain a minimum of voltage drop. To prevent the fridge from discharging the cranking battery battery a relay is inserted in this cable and is controlled by the ignition switch (relay activates and applies power only when the ignition is in the run position.)

I trust that your van battery is not solely on the tow vehicle to charge it. A vehicle alternator will not fully charge a battery in a caravan.

PeterD
FollowUp 4 of 7
FollowupID: 491980   Submitted: Sunday, Apr 01, 2007 at 20:52

Member - Peter R (QLD) posted:

Peter,
That makes it clearer.
Battery in van is an AGM and I charge it before leaving with a Ctek7000.

Pedro
FollowUp 5 of 7
FollowupID: 491990   Submitted: Sunday, Apr 01, 2007 at 21:01

disco1942 posted:

Pedro

That is an excellent choice of charger, I take it that it is permanently installed in the van.

PeterD
FollowUp 6 of 7
FollowupID: 491993   Submitted: Sunday, Apr 01, 2007 at 21:07

Member - Peter R (QLD) posted:

Peter,
No I use it to charge, car ,van and boat batteries as well.

I am getting an Anderson Plug fitted to the Ctek7000 and can then charge the auxiliary battery and the van battery through the Anderson Plug on van or on vehicle.

Have had it for 2 years and it has worked really well, with conventional plugs, so hope the new method works as well.

Pedro
FollowUp 7 of 7
AnswerID: 231028   Submitted: Sunday, Apr 01, 2007 at 17:30

lunchbuckett replied:

peter r there is a simple way come off the run side on the ignition to a constant soloniod relay to anderson plug if it is a long run use 8 mill cable hope this helps
Reply 4 of 5
FollowupID: 491932   Submitted: Sunday, Apr 01, 2007 at 18:06

lunchbuckett posted:

peter it should switch of run side of ignition power off alternator if charging as well
FollowUp 1 of 1
Activities Index
Tasmania Wild West - 3 Days Tasmania Wild West - 3 Days
Devonport and North West - TAS
This is the best way to travel from Launceston/Davenport to Hobart.
Daintree Cape Tribulation Tour Daintree Cape Tribulation Tour
Cairns and Tropical North QLD - QLD
Join us on this fully guided Daintree Rainforest walk, including a wildlife river cruise in seach of
Harley Ride - Yarra Boulevard Tour Harley Ride - Yarra Boulevard Tour
Melbourne - VIC
Take in Melbourne's panoramic views on the back of a roaring Harley Davidson motor bike!
Day Spa Pedicure & Manicure Treatment Day Spa Pedicure & Manicure Treatment
Brisbane - QLD
It's time to be spoilt!
Book Now - Things To Do
AnswerID: 231038   Submitted: Sunday, Apr 01, 2007 at 17:51

Wingwang replied:

used a Redarc VSR on my setup after flattening the battery
$100 incl post was best price could find on the caravan forum
Reply 5 of 5
FollowupID: 491939   Submitted: Sunday, Apr 01, 2007 at 18:31

disco1942 posted:

If it is only the fridge you are supplying $100 is a bit much - a headlight relay can be obtained for less than $10 - just wire the coil to something that is only alive when the motor is running.

PeterD
FollowUp 1 of 4
FollowupID: 491950   Submitted: Sunday, Apr 01, 2007 at 19:12

Wingwang posted:

and blow up the electronics of the vehicle because it causes sparks or stuff.
$100 is cheap over repairs to electronics. my auto electrician said was the best device and told me why and so you buy it.
what are your qualifications and expertise in this field and do you guarantee the vehicle electronics and computers with your advice.
FollowUp 2 of 4
FollowupID: 491966   Submitted: Sunday, Apr 01, 2007 at 20:23

jamess posted:

A relay activated by a unit that only operates when the engine is running , such as the charging indicator light will work fine. Just make sure you purchase a diode protected relay unit. When the magnetic filed of a coil is collapsed, it induces a voltage spike. This may cause a computer to fail. The diode, in a diode protected unit, will prevent this.
jims
FollowUp 3 of 4
FollowupID: 491985   Submitted: Sunday, Apr 01, 2007 at 20:58

disco1942 posted:

Wingwang

You ask of my qualifications. In my working life I was a radio technical officer. I am well aware of "sparks or stuff" having worked on intrinsically safe radio transceivers. I have been involved in the the installation of battery systems from flee powered systems to ones like in telephone exchanges and also installed some of the earliest solar systems in Australia. I have been involved in installing two way radio systems and other electronic equipment in police and other vehicles. I have maintained my own vehicle charging systems since the days of 6V systems. I have also studied the subject of battery charging to a much higher level than the average auto electrician.

PeterD
FollowUp 4 of 4