Is my alternator bust? - with resitance/voltage figures - SV650.org

04-05-06, 10:02 AM

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

) 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

)

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

TSM · 04-05-06, 10:06 AM

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.

04-05-06, 11:18 AM

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!

johnnyrod · 04-05-06, 11:49 AM

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.

04-05-06, 12:22 PM

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

04-05-06, 02:12 PM

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

Sid Squid · 04-05-06, 02:21 PM

You're blind.

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

04-05-06, 02:36 PM

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

johnnyrod · 04-05-06, 03:20 PM

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.

04-05-06, 04:17 PM

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

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

04-05-06, 10:02 AM	#1
branny Guest Posts: n/a	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 ) 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 ) any help on this subject will ease my stress levels a little. thanks

04-05-06, 10:06 AM	#2
TSM The Sick Man Mega Poster Join Date: Nov 2004 Location: Peckham.SE.LDN Posts: 4,768	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. __________________ OTR: KTM 690 Duke R 2015 Full Akro SIDELINE: Kwak ZX636 A1P 2002, Red, R&G's, Yoshi, Double Bubble Screen GONE: Kwak ZX-7R P1, Full Akro, Undertray, Screen GONE: SV650S K2 Very Bruised & Without Fairing, Motovation Frame Sliders, R&G Ally Sprocket Toe Protector, HEL 2 Line Setup, GSXR K1 600 RWU Forks, Barnett Clutch & Springs, Penske 8981 Shock, Gilles Ti Rearsets, Steel Barends, Scottoiler, AFAM Chain & Sprockets, Twin FIAMM Horns, Skidmarx Bellypan, Full Micron Zeta Steel System, Cut down undertay. Forum Problems & Information / Site Suggestions

04-05-06, 02:21 PM	#7
Sid Squid No, I don't lend tools. Mega Poster Join Date: Jul 2003 Location: Skunk Works, Nth London Posts: 8,680	You're blind. (No, not really - you'd never find the keyboard if you were, but it's there anyway). __________________ If an SV650 has a flat tyre in the forest and no-one is there to blow it up, how long will it be 'til someone posts that the reg/rec is duff and the world will end unless a CBR unit is fitted? A little bit of knowledge = a dangerous thing. "a deathless anthem of nuclear-strength romantic angst"

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04-05-06, 11:18 AM	#3
andyb Guest Posts: n/a	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!

04-05-06, 11:49 AM	#4
johnnyrod Member Mega Poster Join Date: Jul 2003 Location: Doncaster, oop norf Posts: 2,128	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.

04-05-06, 12:22 PM	#5
branny Guest Posts: n/a	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

04-05-06, 02:12 PM	#6
silent Guest Posts: n/a	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

04-05-06, 02:36 PM	#8
RandyO Guest Posts: n/a	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

04-05-06, 03:20 PM	#9
johnnyrod Member Mega Poster Join Date: Jul 2003 Location: Doncaster, oop norf Posts: 2,128	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.

04-05-06, 04:17 PM	#10
branny Guest Posts: n/a	http://www.thegsresources.com/garage/gs_statorfault.htm this site has the best fault finding flow chart ive seen.