Wiring to rear of Vehicle for Caravan

Submitted: Sunday, Apr 26, 2015 at 12:26
ThreadID: 117626 Views:2477 Replies:3 FollowUps:2
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I was wondering would it be better to take the power directly from the alternator, rather from the battery? Still using circuit breaker and solenoid as if coming from the battery.
My D40 has limited space around the battery area.

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Reply By: vk1dx - Sunday, Apr 26, 2015 at 14:30

Sunday, Apr 26, 2015 at 14:30
Practily speaking I would take power from the battery, run it to a new fuse box and then to the rear of the car. I am guessing that the terminal on the alternator is not easy to get to. And if you happen to leave it loose or it comes loose then that buggers the rest of the car.

See if there is room for one of the fuse boxes shown below. If so then this would also give you a convenient place for fuses for future development and a darn quick way to see or replace a fuse if it blew. What do you need a solenoid for? If it's fused (circuit breaker is just a fancy fuse) then that is all you need.

From Jaycar - 0 Way Blade Fuse Block with LED Indicators. CAT.NO: SZ2008. About $20 and the same fuses as in your car and each circuit can carry 30 amp with a 100 amp input max from the battery.

AnswerID: 552955

Follow Up By: vk1dx - Sunday, Apr 26, 2015 at 14:34

Sunday, Apr 26, 2015 at 14:34

Jaycar 10 way fuse box
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Reply By: HKB Electronics - Sunday, Apr 26, 2015 at 15:28

Sunday, Apr 26, 2015 at 15:28
In modern cars the manufactures tend to use the smallest cable they
can to meet the expected power demand.

This can result in a significant voltage drop over the cable running from the
alternator to the fuse box, to overcome this a lot of manufactures these days
are installing alternators that have remote voltage sensing, the alternator monitors
the remote reference point usually the positive battery terminal or fuse box buss
and adjusts its output voltage to keep the reference at the regulation voltage. This
can mean that under high accessory loads the alternators output terminal may be
for example 1.5V higher than the cranking battery terminal voltage.

So bottom line is if you want a tightly controlled regulated voltage connect to the
usual points depending on what your charging setup is. If your not worried about
a possible widely swinging voltage then you can connect to directly to the alternator.

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AnswerID: 552956

Follow Up By: Ross M - Sunday, Apr 26, 2015 at 20:41

Sunday, Apr 26, 2015 at 20:41
I totally agree with HBK.
My practice of connecting driving light cables directly to the rear of the alt has resulted in very bright 55w globes and never a need for 100w or more as some go for thinking they are better.
The alt terminal will( as mentioned) supply the highest voltage and therefore charge capability for ANY item run off 12 v.
Sometimes with modern vehicles some problems are eliminated by doubling or replacing the alt to battery supply.

Where the battery is charged, any small resistance effect is lessened as the battery becomes charged.
With a constant drain of additional equipment, going from the alt to the battery and then to the appliance/system is less effective.

Working on the alternator you will of course do the work correctly, tighten the connection appropriately, and instal wiring so it is protected and won't chafe. SO, no problems with that method at all.

You will probably do a far better job than Holden has done with the cabling on the Colorados, many thousands of them have to be checked/modded, because no one in QC noticed they were made sus. at the outset.
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Reply By: Member - mike g2 - Monday, Apr 27, 2015 at 10:53

Monday, Apr 27, 2015 at 10:53
Hi cougar, sounds like your after a 'hot wire' to rear utilix/anderson plug? Agree with 1 main cable taking it initially from battery to side wall distribution/fuse box with whatever bits you want added such as relay if required . would look like what's shown in other reply photo, from there good solid wire to rear. this enables other take offs to be made as required for such things as a 12V plug outlet (rear canopy), 12v to a car fridge, 12 for electric brake controller,... etc. Thus all the take offs are not on battery itself, but tucked away on a side wall, I had this done for my navara and patrol by a local auto elect- worked well and fitted well.
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