Charge light dimly lit while running

Hey guys, one for the sparkies

This is probably a real dumb question but,

I have a 06 4.2 ute, I made my own duel battery circuit which has a wire tapped into the charge signal wire to switch a 12v relay (85 terminal)

Which brings on the charge light dimly, barely visible during the day but easy to see at night !

I also had another ute exactly the same when I did field service up north in wa with the same relay set up and same problem (diesel mechanic not sparkie)

I've never tested the voltage on the wire (as sometimes these can be half voltage) but used a 12v test light on it which lit up good when I installed it

I suspect to much draw for the wire but am a bit scared of frying something if I put more power in the wire to help hold the relay once switched ???

Cheers

It might tell you if charging two or just start battery.?
Multi meter will give you some more info

If Im understanding this right, I think where you have tapped into is a Yellow Black wire at the alternator? Probably not the best place to go, Looking at the diagrams in my book this is the alternator sense wire, used to adjust its output. If you have placed an additional load on it between the light and the alternator, you'll change the voltage it "sees" and therefore will adjust the alternator output. This could be why you are getting the light on.

The light being on dimly is due to a difference in voltage between the ignition circuit and alternator regulator.

What type of relay are you using? I'm guessing a constant operation solenoid?

You could try using a smaller standard type relay to switch the constant operation solenoid, hopefully the reduced load will allow the light to go out fully.

Or you could change the relay to switch on with ignition instead of the charge signal wire.

Cheers for your input guys

I can't recall the wire colour and I'm away at the moment, she's never had any charge issues so maybe the voltage being slightly lower is causing it to charge a bit more than required ?

Yea Yendor its a bog stock relay might try finding a relay that requires less current to pull, not to keen having it switch with the ign, fool proof setup how it is now !

Grazer