139qma/b charging problem ? By rob63 (Read 1,110 times)

[rob63]

We`ve got a 3 month old scoot in work where the owner has to charge the battery every couple of days or it dies. Battery voltage when running is about 12.4 tops. I checked the charging system, the white and yellow wires from the stator are only putting out between 8 and 10 volts each tops. If I disconnect the regulator the voltage from each wire goes up to about 32. I swapped the stator and flywheel to no avail. Swapped the regulator in case it was causing a problem but all remained the same. Any thoughts chaps ?

[trashtruck12172]

i think the stator only puts out ac voltage, not dc. voltage is converted by the regulator. increase rpms to 2000/3000 and retest. stator may not put out much voltage at idle.

[rob63]

The rpm was about 5000 when I tested the stator AC voltage bud. Sorry I didn`t make that clear

[tvnacman]

You need to balance the load.
Has this ever charged correctly?
Something is off.
Tell us any lighting problems? Change any lights or add any electrical items?
Lighting is it ac or dc?

John

[rob63]

Lighting is AC (only works with engine running). Scoot is 3 months old, totally stock with 381km on the clock. I PDI`d it when new and charging was 13.5 volts at battery.
Had a fiddle with it this afternoon, removed battery and started bike by kickstart, yellow and white wires were down to 6 volts each without battery fitted
Then fully charged battery and refitted, double checked earths, connected an extra lead with crocodile clips each end from engine to negative battery terminal, at that point for a split second I started getting 14 volts at battery, then that disappeared and went back to 12.3. I don`t know if that was because of the extra earth lead or just a blip in the system, it didn`t give me chance to check.
I`m back in work on Monday so hopefully will have a bit more time on it.

[tvnacman]

A bad battery could be the cause of your symptoms. If you can check it with a different battery I would do that. You sound like your on the ball with electrics.

John

[Alleyoop]

Yes a bad cell in the battery will cause that and initially may show good but that is just surface charge.
Alleyoop

[rob63]

Cheers lads. I did try another battery on Wednesday with no difference, but it wasn`t fully charged. Will try a charged battery on Monday to see how that goes.

[tvnacman]

I agree with checking grounds and using heavier gauge wire too.

John

[rob63]

Charged battery right up and drop tested, all seems fine with that. Tried another charged battery on scoot to see if that made a difference but no change.
Checked resistances on stator wires and thats all good (it should be as its new).
Tried two new regulators on there but all the same.
Checked and cleaned all earths but made no difference, even tried popping on the extra earth lead as before to replicate the 14 volts but it didn`t happen again.
Only thing I can say for sure is the white stator wire gives 10v and yellow gives 8v when connected. Disconnect the stator plug at regulator and I get 26v at idle which seems right. So it would point to regulator but it isn`t (having tried replacements) . I checked resistances at regulator plug and they`re good as well.
I think this one will have to go back to the distributor....

[tvnacman]

pull your headlight bulb and see if things go back to normal.

[Alleyoop]

From the readings your getting the stator is bad. Your readings should be much higher that what your seeing.
Alleyoop

[rob63]

Jan 18, 2016 8:06:28 GMT -6 tvnacman said:

pull your headlight bulb and see if things go back to normal.

I`ll try it tomorrow bud.

From the readings your getting the stator is bad. Your readings should be much higher that what your seeing.
Alleyoop

That`s the vid I used Alley. I`m getting 26v at idle (goes up with rpm) with the multiplug disconnected. The problem seems to be when its connected, it`s just not sending enough to the regulator to charge the battery.
I had a word with the distributor and they`re sending down another regulator, if it works then I`ve got two 6 month old reg`s on the shelf which are faulty. What would be the chances of that ?

[Alleyoop]

Ah, did not read that part of you getting 26v and higher when revving. So then its a bad R/R/. And they are all made in china so QUALITY IS NOT THEIR NUMBER 1 PRIORITY Some folks have bought up to FIVE R/Rs before they got a good one.
Alleyoop

[rob63]

Yep looks like the RR Alley. It still ain`t great but at least I`ve got just over 13v at the battery now. Those two RR`s on the shelf can go back to the distributors.