Wiring to rear of Vehicle for Caravan

Submitted: Sunday, Apr 26, 2015 at 12:26

ThreadID: 117626 Views:2997 Replies:3 FollowUps:2

This Thread has been Archived

Cougar 55

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.

Cheers
Brett

In Search of the Perfect Wave and not the one from the missus, ( see u later)..lol

Member
My Profile My Blog My Position Send Message

Back Expand Un-Read 1 Moderator Share

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

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.

Lifetime Member
My Profile My Position Send Message

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.

FollowupID: 838710