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Post by motomech on May 3, 2008 13:12:16 GMT -5
Charging and dead battery problems.
Preliminary testing;
Think K.I.S.S. here. Testing ALWAYS begins at the battery and the vast majority of testing will end here as well.
Drains on system;
This should be checked first. Placing the voltmeter in-line(in series) with one of the battery cables and it's relative terminal(doesn't matter which one)and with the key off, the voltmeter reading should be zero. On tri-phase systems, there are three diodes in the rectifier and each diode represents approx. 4 volts. Therefore, drain readings of 3 to 5 volts would indicate a failure of one diode and readings of 7 to 9 volts, two diodes. Systems on these scooters use a combination regulator/rectifier ASM. and these are replaced as a unit. Drains can also be caused by by shunts to ground. These are best tracked down by isolating circuits, either by pulling fuses, or separating connectors(while watching the meter).
All 250's and above displacment scooters are tri-phase systems, while it is my understanding the GY6 based scooters(125/150's)use a single-phase system. For these, the "at battery" tests apply, but some details(such as voltage readings and diode location and replacement) will be different.
Charging;
With a known good battery installed(see Battery testing, in this section), charging is tested by placing a volt meter across(in parallel)the battery. With the engine at idle, establish a base-line reading. Now, rev the engine slowly, taking care that the scooter does not roll off the center stand and launch itself. At some point, the needle should deflect up wards by approx. a volt. If the needle deflects up wards, the charging system is functioning.
Reading of over 14 volts would indicate that the regulator is malfunctioning and again, the rectifier/regulator ASM should be replaced.
Zero charging would indicate a stator/rotor failure and the testing procedures out-lined in the service manual should be followed.
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Post by kink on Jul 13, 2008 17:27:17 GMT -5
I have been having trouble with my electric start lately. It seems to have enough juice to crank once or twice but then winds down and dies. I can kick start with no problems.
I tried this test to see whether there is some kind of electrical drain on the battery that is causing it to be low. These are the results I got:
With the key turned off and the meter hooked up in series to the battery I got 10.4 volts. I tested this by disconnecting the black terminal and inserting the volt meter between the black cable and the battery post.
With the key turned off in parallel (one probe on each battery terminal) I got a reading of 11.4 volts.
With the bike at idle and the volt meter in parallel I got a reading of about 11.6 volts. Revving the bike up brought the reading to just shy of 12 volts (around 11.95 at the most).
From what you say about the in series test, a reading of 10.6 volts would indicate that my rectifier is blown. Is there a conclusive method to determine whether this is the case?
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Post by thedannymullen on Jul 13, 2008 17:48:06 GMT -5
The reason you measured 10.6 volts when in series is because the voltage was divided down due to the scooter load. You have to measure voltage with the meter in parallel with the battery. You measure Current(amps) with the meter in series.
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Post by kink on Jul 13, 2008 18:40:28 GMT -5
Ok, that seems to contradict what motomech said in his post. Either way, voltage in parallel was less than 12v across the board, even when revving the engine. Something isn't adding up here.
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Post by pukame2 on Jul 13, 2008 22:19:12 GMT -5
Yep. I refer to it as the Keep IT Simple & Sweet principle.
I changed out my battery to a 9A version.
Disconnected the stereo and alarm.
Ordered a LED tail/brake lite. Saw an earlier posting and that influenced my action.
These with my built in float charger should keep my battery peaked at all times.
Earlier postings and their recommendations have really kept my scoot running right. Its comforting to know that this forum has some very smart dawgs.
Continue good riding.
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Post by thedannymullen on Jul 14, 2008 0:02:12 GMT -5
Voltmeters are connected in parallel to measure the voltage across something. Since you did not receive 12v in parallel I would suggest you check 2 things.
1. Disconnect the battery and measure it if it is 12V then the scoot could be loading the battery when connected.
2. Start the scoot then with battery disconnected measure the voltage to see if it is say 12.5+ at idle and goes up when the engine is rev'd.
If 1 and 2 are true you may have a bad battery. If only #1 is true I suggest troubleshooting what is drawing power. If only #2 is true you most likely have a bad battery. If #2 is false then I would suggest checking the scoot electrical system backwards to the stator.
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Post by thedannymullen on Jul 14, 2008 0:10:18 GMT -5
Charging and dead battery problems.
This should be checked first. Placing the voltmeter in-line(in series) with one of the battery cables and it's relative terminal (doesn't matter which one) and with the key off, the voltmeter reading should be zero. I would assume he made an error here and meant to check the current under this condition. The current should be 0 when the scoot is off. Unless you have electronics like an alarm system that is active while the scoot is turned off. |
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Post by kink on Jul 14, 2008 8:40:04 GMT -5
Voltmeters are connected in parallel to measure the voltage across something. Since you did not receive 12v in parallel I would suggest you check 2 things. 1. Disconnect the battery and measure it if it is 12V then the scoot could be loading the battery when connected. 2. Start the scoot then with battery disconnected measure the voltage to see if it is say 12.5+ at idle and goes up when the engine is rev'd. If 1 and 2 are true you may have a bad battery. If only #1 is true I suggest troubleshooting what is drawing power. If only #2 is true you most likely have a bad battery. If #2 is false then I would suggest checking the scoot electrical system backwards to the stator. Thanks for that man! Bone for you! I'm going to try this tonight. I understand what you say about the in line check being for amps, I'll run that check as well tonight and see what I can come up with. Need to get some alligator clips for the meter though. Either that or enlist the wife's help for a couple of minutes. Trying to use probes with one hand and run the throttle with the other is a PITA.  |
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Post by thedannymullen on Jul 14, 2008 22:12:16 GMT -5
Glad to know that my 4yrs of electrical engineering finally paid off..
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Post by kink on Jul 14, 2008 22:20:43 GMT -5
Ok, this is totally wierd.
When removed from the scoot, the battery is showing 11.48 volts. Incidentally, it is a YUASA which I'm told is quite good.
With the battery removed from the scoot, testing at the battery connect wires while the scoot was running showed around 6.4 volts. This increased slightly when the throttle was open, but nowhere near 12v. In fact I don't think it even broke 7 volts.
When tested in series for amps with the scoot off, the meter read zero.
After running all these tests and hooking the battery back up, the electric start works fine. Before I started these tests it would not turn over (electric start would crank once or twice and then wind down to nothing). I honestly have no idea what the problem would have been. The fact that the scoot is producing nowhere near 12v when idle is concerning though... any ideas?
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Post by thedannymullen on Jul 14, 2008 23:24:45 GMT -5
Ok so with the scoot running and no batt connected, but measuring across the leads that would normally connect to the battery only measured 6.4-7 volts. In addition to the fact that the other day with the battery connected and engine running you never got over 12v, it appears to me that you possibly have something wrong in your charging system. My suggestion is:
1st to trace the connections back to the motor and look for any loose wires.
2nd Well I really don't know, I don't have my scoot yet to tell you how to attempt to measure the voltage out of the stator prior to the regulator.
You could verify all ground connections, I know sometimes you can have a bad ground you can get weird results.
Basically if no loose connections are found you need to see what component is not performing as advertised. I am not sure how to tell you further troubleshooting as I don't have my scoot as a reference yet. It is scheduled to arrive this week, I hope.....
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Post by isawhim on Jul 15, 2008 1:18:18 GMT -5
Sounds like a dead diode in the regulator... or... there is a partial short in the system.
If the rest of the bike functions, you should assume the regulator is the issue. The DC converter/rectifier inside is shot. (Might have been a manufacture defect, or due to a short in the system.)
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Post by kink on Jul 15, 2008 6:40:09 GMT -5
Ok, so these three items on the troubleshooting list:
1) Check all connections, particularly grounds, for loose connections.
2) Check regulator for proper function. How do I do this?
3) Check stator for proper output. I think I saw a post on this somewhere...
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Post by wf1761 on Jun 18, 2009 22:01:05 GMT -5
To check the charging voltage put the black lead from your volt meter on the negative terminal and the red lead on the positive terminal of the battery. Have the meter turned on and on the 20 volt or higher scale. With the engine running after it warms up for at least two minutes it should read between 13 to 16 volts on the meter. If it reads anything else you have a problem. Replace the Rectifier/regulator.
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Post by maxiscooter on Jan 24, 2010 12:03:49 GMT -5
I know it doesn't mean much to you guys but what motomech said about checking voltage and amperage holds true for scooters, cars, and even airplanes. I am a licensed airframe mechanic and you check voltage the EXACT same way. Electricity is electricity, it doesn't matter where it is. Airplanes usually deal with higher voltages and amperages than cars, boats or scoots but its the same exact principle.
Flow charts can help alot in the diagnosis of electrical issues. Starting at the battery is a good place to start, I totally agree.
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Post by davidnitro on May 28, 2010 23:29:06 GMT -5
OK im new but i know how to work on stuff. I have a 50cc united motors x-peed. I bought it the guy said all it needs is a new battery because of it sitting. I put a brand new battery fully charged within 3 days the battery couldn't turn over the engine. So i grabed the voltmeter and at the battery with it running only 0.39v were being put out, with half to open throttle it only had 0.43v. I think that the strator and alternator went bad. It does have 10k miles on it so idk where to start? Thanks David.
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Post by D-cat on May 31, 2010 21:45:35 GMT -5
The stator is the alternator. The regulator is the other suspect... and at least with cars, when one goes bad it can drag the other one down with it.
These seem like exceptionally low voltages though. Do the headlights work while the engine is running?
I think I'd start by checking all the electrical connectors and grounds, probably in this case starting from the stator and working my way out.
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Post by JR on Jun 6, 2010 12:18:27 GMT -5
Oh me it's simple; The stock 6-pole stator is actually a very simple device. There are 6 windings total. 5 of these windings are wired together in series and are responsible for charging your battery and supplying power to your headlights & auto-choke. Positive voltage flows from the stator through the the yellow and white wires. The black wire is ground back to the stator. It must be noted that these three wires are completely isolated from the ignition system. You can unplug the 3-prong stator wires harness and the engine will still fire up just fine. The 6th winding wrapped up in white layering seems to be dedicated to supplying the CDI with AC power. The blue/white wire leading to the black magnetic pickup is called the trigger wire. This wire is responsible for telling the CDI when to send power to the ignition coil, firing the spark plug. The 6 and 8 pole stators are similar in function, the key difference being that the 8 pole stator as 2 additional poles dedicated to charging. scooterdoc.proboards.com/index.cgi?board=electrical&action=display&thread=294 |
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Post by joethursday on Nov 4, 2010 12:58:16 GMT -5
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Post by prophecy on Dec 23, 2010 18:49:12 GMT -5
can u help i know nothing on electrical . my signal lights wont work and my night lights wont work . my brake and rear night lihgt works. i work at night and really need to fix this so i can get to my job.need help.
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Post by tvnacman on Dec 24, 2010 1:13:31 GMT -5
do you own a meter
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Post by saoul on Apr 6, 2011 17:03:27 GMT -5
Thanks for all of the posts on this. I just got my scoot and have done all of the tests you posted. My problem seems to be a pitifully small capacity battery supplied by the factory. A trip to WalMart for a higher amp hour one will do the trick. Again, many thanks!!!
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Post by justthisguy1292 on Jun 11, 2011 15:52:51 GMT -5
I was wondering if you could help me reason through trouble shooting a Roketa mc-07-150 scooter. It has a long history, but I'll skip stuff that doesn't seem important. So there is a magneto(generates electricity), regulator/rectifier(grounds any extra power generated by the magneto and converts it from AC to DC), wiring harness, battery, and head lights involved in this problem. I replaced the wiring harness because some of the wires had shorts. Two reg/rect's have fried( one literally had a melt down). Head lights keep blowing out. The head lights i believe are either symptom of being pieces of Chinese junk, or (but most likely and) an obvious sign that the reg/rect has blown. Normally, from what I've read online, you can usually replace a reg/rect and everything should be fine, but they keep blowing. So that makes me to suspect the stator in the magneto is shot, making too much power and frying the reg/rect and then blowing the headlights and probably causing those shorts in the wiring harness. I apologize for how long this is. I'm almost done. So after replacing the wiring harness, headlights and reg/rect, a voltmeter on the terminals of the battery with the scooter at 5k rpms slowly climbed to 13.5 volts. I road the scooter for about an hour, the headlight blew, and I took out the dead bulbs. NOW the battery reads 15.17 volts at 5k rpms. I figure with new bulbs plugged in that will bring it down to 14.5 volts and then it'll be exactly where it is supposed to be. This problem should not have fixed itself like this. I'm pretty lost. My best guess is to replace the reg/rect again, put in a new stator, replace the headlights, and hope for the best. That'll cost over $100 so I want to be sure, before I do anything.
After riding it to campus the the battery went back to slowly working up to 13.5 volts. And after a minute or two of running it slowly got up to 14.5, but this is all without headlights plugged in. I plugged in one of the old reg/rect's to see if it did the same thing, but it just didn't charge at all. So the reg/rect that I've been using is either fine or messed up in some new way that I've never heard of before.
p.s. I'm fixing this for my brother.
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Post by 86helix on Apr 9, 2012 19:28:29 GMT -5
I know this is a little late but I have found some interesting values regarding this very same subject. I hope this helps someone.
My scoot is an 86 Honda Helix CN250. Just this past week I could not get one single start out of a brand new Yuasa 10Ah battery.
It began with a starter that barely turned and could not start without a boost.
I took current readings using a DC current clamp while watching my voltage drop dramatically.
They were 6.5V @ 70+Amps! I thought a bad starter so rebuilt the Mitsuba starter with the SM-8 brush rebuild kit for $20.
Note to Helix owners, you can drop the starter by removing the coolant supply line and small hands it's a real tight space but works.
The result was the same values (note the brushes were almost all but non existant)
Spent my Easter weekend with the scooter in pieces looking for draw on the battery.
Seems when I took all the fuses out here was the draw values with the key on:
Dash 0.7A
Brake (w. brake light on) 2A
Headlight 11A !!!!
Herein was my draw down. Took out the headlamp bulb and found that both the 55W and 60W elements were on all the time. That works out to be my 11 amps of draw!
Turns out my Hi/Lo beam switch was worn and jammed in the mid position. A little brake cleaner to remove the old gummed grease. My draw dropped to 5A and allowed me to startup a dozen times before not being able to start (under 7V).
Normal starter draw is 44 amps at a fully charged new battery of 13.86 volts.
Hope this helps someone.
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Post by 86helix on Apr 9, 2012 19:37:07 GMT -5
One last note. Normal charge voltage is just above 14V. With a 5A + .7A (headlight + dash) draw there is approximately 1.3A charge current left filling the battery. Just enough to cut even when running the high beams.
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Post by tradeiswear on May 14, 2012 0:17:53 GMT -5
so good
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