Is my alternator bust? - with resitance/voltage figures
 

ive been having problems with my battery going flat.

with the engine running i get 14.3V across the battery.
At 5000 rpm i get 13.9V

This means to me that everything is working.
But the battery does keep going flat.

The three yellow wires from the alternator to the regulator/rectifier all give 0.001 ohms between them. This is low, but im prepared to blame my multimeter for this as with the engine running, they give 80V AC across all pairs.
baffling.

Surely an alternator cannot be faulty if it is giving 80V AC the the RR and 14.3 to the battery.

???

I did a diode test on the RR and i only got 600mV redings from the red to the yellow wires.... im getting a RR from jakeRS (cheers 8) ) im HOPING this will solve it.....
but im still worried about the low resistance across the alternator stators.

note: there is no continuity from stators to earth (this is good :lol: )


any help on this subject will ease my stress levels a little.
thanks

Looks like battery from first glance. A freinds TL had exactly the same problem, he got a new regulator but the values were still the same and the batt still went dead. Got a new battery and the bike works fine now. I might be wrong though.

I had the same on my bike a couple of months ago, same sort of readings. It turned out to be a knackered battery in the end!

Your readings sound fine. Did you measure the 80V with the alternator plug disconnected? You should have done, if not the numbers would be lower, so sounds fine anyway. Other check to do is for continuity between the three alternator wires and earth - should be nothing otherwise obviously it's shagged. Sounds like the battery to me too. Also if the bike runs okay once started the charging system has to have a little bit of life in it, at least.

yeah...
i was sure it was the battery, because most of the values on my (value) multimeter looked good....
but ive had the battery checked and they cant see anything wrong with it, it happened on one battery and then on this new one too.... sooooo its GOT to be the reg/rec.

cheers

how do you check the alternator out of interest, sid squid explained the reg/rec but i dont think the alternator has been mentioned...unless im blind

andy

You're blind.


(No, not really - you'd never find the keyboard if you were, but it's there anyway).

RRs can work intermittently and be very hard to diagnose, quite often, they will work properly while they are still cool, then once they warm up, they don't

my guess is you have a bad RR

after you have ridden a half hour or more, get everything good and hot, then check the voltage

Good call Randy. If the battery is new and has been FFFF'd then I too would suspect the RR giving it a hard time.

http://www.thegsresources.com/garage/gs_statorfault.htm

this site has the best fault finding flow chart ive seen.