New Prado - Power to Van only with ignition on
Submitted: Sunday, Apr 01, 2007 at 16:26
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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
Reply By: disco1942 - Sunday, Apr 01, 2007 at 17:21
Sunday, Apr 01, 2007 at 17:21
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
AnswerID:
231027
Follow Up By: Member - Peter R (QLD) - Sunday, Apr 01, 2007 at 18:04
Sunday, Apr 01, 2007 at 18:04
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
FollowupID:
491928
Follow Up By: disco1942 - Sunday, Apr 01, 2007 at 18:27
Sunday, Apr 01, 2007 at 18:27
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
FollowupID:
491938
Follow Up By: Member - Peter R (QLD) - Sunday, Apr 01, 2007 at 18:59
Sunday, Apr 01, 2007 at 18:59
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
FollowupID:
491946
Follow Up By: disco1942 - Sunday, Apr 01, 2007 at 20:41
Sunday, Apr 01, 2007 at 20:41
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
FollowupID:
491974
Follow Up By: Member - Peter R (QLD) - Sunday, Apr 01, 2007 at 20:52
Sunday, Apr 01, 2007 at 20:52
Peter,
That makes it clearer.
Battery in van is an AGM and I charge it before leaving with a Ctek7000.
Pedro
FollowupID:
491980
Follow Up By: disco1942 - Sunday, Apr 01, 2007 at 21:01
Sunday, Apr 01, 2007 at 21:01
Pedro
That is an excellent choice of charger, I take it that it is permanently installed in the van.
PeterD
FollowupID:
491990
Follow Up By: Member - Peter R (QLD) - Sunday, Apr 01, 2007 at 21:07
Sunday, Apr 01, 2007 at 21:07
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
FollowupID:
491993