CHARGING HELP NEEDED ON 49CC CHINESE SCOOTER By jerimiah (Read 1,387 times)

[jerimiah]

I acquired a basket case 49cc chinese scooter. It runs good now after working on it and replacing some parts. The main electrical part I replaced was the cdi. The battery in it was bad so I have been kick starting it and using the bike with no problem, except the blinkers would not have enough electricity to work although the headlight stays on all the time with no problem.
Today I put in a new battery and everything works great including the blinkers and horn, except I checked if the battery was charging and it is not. With engine off battery read 12.25v and with engine started and high rpm does not increase. I checked at the back of bike and unplugged the wires coming from the stator. I checked the yellow and the white wire and used the green for ground for the vom meter. At idle both wires read 13-16 vac and at really high rpm 105 vac. Shut motor and I plugged the connector from the stator back in. I pulled the plug in the front on the rectifier and tested the red fused wire coming from the battery and it was 12.25v. Started the scooter and tested the white and yellow wires at rectifier plug and got same readings as the plug at the back of the scooter. I pulled the fuse on the red wire going from the battery to the rectifier plug and plugged the plug back into the rectifier. I took a volt reading on the red wire coming from the rectifier to the fuse and got at idle 5v dc and at very high rpm 9v. Then I changed the meter to 10amps dc and put the test wires between the place where the fuse is removed, on the red wire coming from the rectifier to the battery, and it read 1.4 amps at idle and at high rpm.

I am trying to figure out why I am not getting the 12 to 14 volts dc that should be going to the battery.
Can the rectifier go bad so it only sends lower voltage, things I read say that usually if it goes bad the volts get too high?
Could it be the stator?? Also.... why are there 2 wires, yellow and white bringing ac voltage from the stator to the rectifier? Is there a way to check the rectifier? Am I getting enough ac volts to the rectifier?
Any help is appreciated.

Read more: 49ccscoot.proboards.com/thread/9588/charging-problem#ixzz389jPOSXd

[Alleyoop]

One wire from the R/R goes to the battery for charging and the other is for some of your lighting.
So from all that you did the R/R is toast, which usually go bad if you have a bad battery or disconnect the battery and run it that way. So you blew your R/R due to not replacing your bad battery.
Alleyoop

[Bashan]

1. Test the stator in series, that is one probe in a supply wire and ground the other
2: Unplug the stator connector. Set your multi to AC voltage (up to 100v AC if not an auto ranger) and ground one probe IN THE STATOR GREEN CONNECTOR OF THE PIGTAIL. Do not ground it to the frame to avoid interference. Put the other probe in white wire and start the engine. Give it some RPM and you may get up to 60v AC or even a little more. Down to 40 would be acceptable.
3: Same procedure for the yellow wire, it should be a little less. If the voltages aren't within these ranges your stator is bad. Plug the stator back in.
4: If the stator voltages are good start on the R/R. Leave the R/R PLUGGED IN. Set your multi to AC low volts, no more than 50. Ground one probe to the R/R green to avoid interference. Test the yellow wire, you should get 10 to 13 v AC depending on RPM and what lights are on.
5: Test the white wire the same way, up to 15v AC is acceptable, less than 12 suspect.
6: Test the battery terminals set at DC with some RPM, 13 to 14.75v DC is acceptable. Anything outside of the above parameters is a bad R/R.

The G/Y/W single phase GY6 stator uses one long white wire through the stator to generate AC voltage dedicated for the charging circuit. About halfway along the wire a yellow wire taps into the center of the white and is used for AC to drive the headlights etc. That's why there's two wires that are both AC.

Now Alley is 100% correct, by not using the battery you were forcing the current through the yellow and the R/R will take some of this but soon poof. Even if you have the battery hooked up, if it gets bad enough it actually becomes a resistor and starts refusing to let electrons through especially if a plate shorts out. Make sure you test the stator like I outlined above, your results from your testing were a little screwy but I agree with Alley it's probably your R/R which it usually is.

Your blinkers quit working and then started back working because they are DC and run off of the battery. So the AC voltage coming from the yellow never made it to the blinkers, or dash lights, or tail lights, or any of the other DC DOT mandated lights. So you may want to run through the tests again to make sure you did it right and then check with us before you order parts. Rich

[tvnacman]

It sounds like a regulator/rectifier .

John

[jerimiah]

Thanks for the info. I ran the tests again as you asked and everything was ok except for the red charging wire going from rectifier to battery. I ordered the rectifier on ebay and should be here Friday. From the picture on ebay it looked identical physically to the 4 wire one I have now and I thought I could just plug the new one in and good to go. I have been reading that sometimes replacement rectifiers are wired differently and it might not be compatable with my scooter plug wiring. So.... what to do to figure this out. If I plug it in and it's not like the old rectifier can I hurt the new rectifier or my scooter. Is there a way to figure out the prongs on the new rectifier? The old rectifier I have now is wired like this: Looking at the rectifier's plug with the plastic nub ( the plastic piece that protrudes out of one side of the plug that is used to lock the scooter's side of the plug in place) on the bottom of plug: top left is Green, Top right is white, Bottom left is yellow, bottom right is red.

Another big question I have is about how the ac/dc system actually works together. From what I have read from your post and others online I understand that the white wire is being fed ac voltage from the stator and so is the yellow wire. With my bad battery, which even when charged was only about 4v, the headlights and tail light and brake light worked, which must have been from the ac being generated. When I tried to use the blinkers I would just get a buzzing noise from the blinker relay because not enough juice to run the blinkers. Now I have a new battery that is slowly running down because it is not charging. I am confused about the dc and ac votage. My headlights, tail and brake lights were working off the ac voltage, but when I look at the bulb it says 12v dc. The same for the all the bulbs on the scooter including the blinkers. Can these bulbs run on ac and dc, and when the bike is at higher rpm isn't the ac voltage much higher than 12volts. Is the ac and dc running through the wires at the same time?

Jul 21, 2014 21:53:18 GMT -6 Bashan said:

1. Test the stator in series, that is one probe in a supply wire and ground the other
2: Unplug the stator connector. Set your multi to AC voltage (up to 100v AC if not an auto ranger) and ground one probe IN THE STATOR GREEN CONNECTOR OF THE PIGTAIL. Do not ground it to the frame to avoid interference. Put the other probe in white wire and start the engine. Give it some RPM and you may get up to 60v AC or even a little more. Down to 40 would be acceptable.
3: Same procedure for the yellow wire, it should be a little less. If the voltages aren't within these ranges your stator is bad. Plug the stator back in.
4: If the stator voltages are good start on the R/R. Leave the R/R PLUGGED IN. Set your multi to AC low volts, no more than 50. Ground one probe to the R/R green to avoid interference. Test the yellow wire, you should get 10 to 13 v AC depending on RPM and what lights are on.
5: Test the white wire the same way, up to 15v AC is acceptable, less than 12 suspect.
6: Test the battery terminals set at DC with some RPM, 13 to 14.75v DC is acceptable. Anything outside of the above parameters is a bad R/R.

The G/Y/W single phase GY6 stator uses one long white wire through the stator to generate AC voltage dedicated for the charging circuit. About halfway along the wire a yellow wire taps into the center of the white and is used for AC to drive the headlights etc. That's why there's two wires that are both AC.

Now Alley is 100% correct, by not using the battery you were forcing the current through the yellow and the R/R will take some of this but soon poof. Even if you have the battery hooked up, if it gets bad enough it actually becomes a resistor and starts refusing to let electrons through especially if a plate shorts out. Make sure you test the stator like I outlined above, your results from your testing were a little screwy but I agree with Alley it's probably your R/R which it usually is.

Your blinkers quit working and then started back working because they are DC and run off of the battery. So the AC voltage coming from the yellow never made it to the blinkers, or dash lights, or tail lights, or any of the other DC DOT mandated lights. So you may want to run through the tests again to make sure you did it right and then check with us before you order parts. Rich