How to wire up a 1 wire alternator

sublimemike · Post by **sublimemike** » Wed Oct 22, 14 9:41 pm

I'm in the process of upgrading my alternator and this thread has come at the right time. I'm running a delco ray single wire connected to the starter relay. I've upgraded to the merc c class fan set up that draws about 38 amp (almost 50 on start up) then there are the lights , lecy fuel pump etc. I've no way of testing the alternator max output but looking at the Volt meter I suspect its on its limit. I ended up going to an alternator exchange place and sent then some pics of my current(sorry) set up. They sent me out a 95amp unit identical on the exterior to what I have. Bolted it on and fired her up just 12v on the volt meter. Turn the lights on and no charge...rang them up to see if it was tested and they said I must have earthed a wire and blown a fuse on my fuse box. Having read this with the link I sent it over to them as I had stated it only had 1 wire connected. They have now told me to try running a link between the main wire battery terminal on the alternator and the ignition spade on the alternator. The original wiring for the ign. light on the alternator is long gone so I can only anticipate some splicing and chopping on the loom (messy) which is a route I am reluctant to go down. Does this link have a chance of working ?

The shop has a reputable reputation but the fact they haven't heard of 1 wire alternators worries me, maybe they just don't know yanks.

Thoughts please

MilesnMiles · Post by **MilesnMiles** » Wed Oct 22, 14 10:11 pm

Mike, just a thought,but did you rev the motor sufficiently to get the alternator to work?
As I understand it, they need approx 1300 rpm to kick in. After that it will charge Normally until you turn the car off. That is the case with my one wire alternator.

sublimemike · Post by **sublimemike** » Wed Oct 22, 14 10:38 pm

Can't remember but I did read that. The guy at the alternator place said it needed a bulb (meaning the ignition light) and consequently the ignition lead to make it work . I'll check but I think they sold me a 3 wire unit

cadboy · Post by **cadboy** » Thu Oct 23, 14 6:54 am

You can easily convert to a 2 field wire system and electronic regulator

sublimemike · Post by **sublimemike** » Thu Oct 23, 14 2:00 pm

Usefull - thanks. Any ideas on hooking the battery wire terminal up to the ignition spade as they have recommended?

sublimemike · Post by **sublimemike** » Sun Nov 09, 14 6:18 pm

I got to the bottom of this for anyone else that is looking at 1 wire alternators. Basically you need to make sure the voltage regulator within the alternator is a "self exciting" one if your looking at 1 wire

The regulators look very similar but the self exciting one activates at lower revs rather than the stock regulator that relies on voltage leakage to kick in the charging process. TBH the advantages of the 3 wire set up mostly outweigh the convenience of a 1 wire set up but I'm not about to change my wiring as what I've got works now with a 100 amp unit