18R Electrical System (alternator, voltage reg +battery)

[MorgzMods]

Hi all,

after a bit of screwing around I now have a new remanufactured alternator installed in the RA40 (18RC)
I have a toyota OEM replacement 12v voltage reg, that I've swapped plugs on to wire up.
And I now have a brand new red top optima.

Runs nicely, no trouble. charges at 13.5 in idle, rising as you rev it (still in idle) but this is were my worries start, it hits 15.3v in the higher revs.

Where should I start looking to stop that? with all my recent messing around I know i should of gone for an alternator with a built in reg (EA 80amp for example) but I'd love to run with what I have now installed.

This is my second OEM voltage reg, when my last battery died (it have previously been waay over charged by the factory voltage reg) I found the coating on the copper looms within the reg to be melting off. So i replaced it. I figured it was a by product of a trouble alternator. Is this my issue? Can i check it to see if it's suitable for use at all?

[Dazza]

There should be a sense wire running from your regulator to your battery. This wire is there for your regulator to sense battery voltage. If it has a bad connection anywhere then your regulator wont get a true reading of the battery voltage, so it thinks your battery is not fully charged when it actually is. You will need to get a wiring diagram and see where this sense wire goes and check all the connections. Some systems run the sense wire through the ignition switch and a faulty switch can cause overcharging. Normally 14.8 volts is as high as you want to go.

[MorgzMods]

Cheers for the info Dazza! I was told the local auto elec is pretty decent, I'll try and pop down to him today and find out what he thinks.

[thechuckster]

Dump the oem externally regulated items and fit Ford/Mitsubishi bocsh unit. Not only will it be far more reliable, your charging rate will improve. don't bother getting the current setup looked at, is a waste of peso.

[MorgzMods]

Hahahaha your info always comes too late Charles.

Had the local bloke sort it out, $30 for him to adjust the voltage regulator. Now it sits right on 12v. I'll head back to him in a few days as he said it will need to settle - I'll get him to up it a bit. what's the safest figure for it to sit on? I'd like to be able to run a small audio system and everything without the headlights dimming.

But that's definitely on the list in the future, even if it's me being lazy and grabbing a replacement 'EA falcon' alternator and fitting it rather than going to a wreckers.