Alternators again. I hate em.

Post by **RattyMcClelland** » Tue Aug 04, 2015 6:40 pm

Last week after MOT tickling time my battery lights came on when the revs dropped at low speed driving. Ok so my Lucas refurbed alt is going.

Got a new one as it just ran out of its 1 year warranty.
New one is Delphi I think. Not sure but looks a he'll of a lot better made.

Anyway installed and it charges. But battery light is on.

This happened last time with the Lucas alt and it look 3 attempts of sending back to get the lights out and fully working.

What cause this?

I have still yet to measue voltage output on the alt and battery.

Does the alt have a ground at all?

I'm so annoyed.

Also voltage at the cigarette light never goes above 13.4v. That normal? In the van it's at 14.4v all the time.

mercutio · Post by **mercutio** » Tue Aug 04, 2015 9:36 pm

thats whats causing your light to stay on if you unplug the alternator the light should go out. The plug goes to your ecu and it tells the alternator to work in low voltage mode

Post by **RattyMcClelland** » Tue Aug 04, 2015 9:47 pm

mercutio wrote:thats whats causing your light to stay on if you unplug the alternator the light should go out. The plug goes to your ecu and it tells the alternator to work in low voltage mode

What's causing the light to stay on?

Yes if I unplug the alt the light goes out and voltage drops.

mercutio · Post by **mercutio** » Tue Aug 04, 2015 9:48 pm

its not producing enough

Post by **RattyMcClelland** » Tue Aug 04, 2015 9:57 pm

mercutio wrote:its not producing enough

It's a brand new recon alt. That's 4 out of 6 recon alts not working.

mercutio · Post by **mercutio** » Tue Aug 04, 2015 10:04 pm

and another 2 if you count mine lol

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Wed Aug 05, 2015 8:37 am

You haven't got a high resistance on one of the leads out of the alternator, have you? (and yes, an alternator will have an earth connection, otherwise the circuit doesn't work - can't recall if that's a cable or via the block on a lude though)

also... your battery is a lightweight racing one, relocated to the boot isn't it?

Try slapping in a standard good meaty heavy one to see if that changes anything? And is it possible to temporarily relocate it back into the engine bay? I think it's worth eliminating all these things that have changed the basic circuit and could be putting extra load on it, while getting to the bottom of it. That's a LOT of alternators to just keep failing...

Post by **vanzep** » Wed Aug 05, 2015 8:56 am

yep a lot of alternators not up to the job and it also seems a lot of new batteries are not up to the job either - one of my neighbours has had 3 brand new batteries in the last few months as they werent holding the charge and would only take a charge of about 70 percent when they were taken out and tested. Makes you wonder whats going on.
Isnt the alternator earth strap part of the loom that sits ontop of the rocker cover...

Post by **RattyMcClelland** » Wed Aug 05, 2015 1:18 pm

Nope I have a heavy duty car audio battery but is still lighter than oem.

Post by **Merlin** » Wed Aug 05, 2015 1:24 pm

Could it be that which is screwing your alternators? Do you need an high output alternator?