HELP!! - New 124cc ATV barely charging!

[masta]

So I bought an ATV last Sat. and it's been giving me fits.

I just spent the night trying to sort out why my bike dies at night. It seems the charging system is sub-par. When charging, it barely moves past 12.5 V unless revved like crazy where it will finally get up to 13V unless you turn on the lights in which case the battery slowly dies until the bike dies. We tried a different battery that is good, and it wasn't as good as the one in my machine!

I could only ride in the day, but that would suck.

When taking off the battery cables while running I measured 2.5-3V which is miles off the 14.2V my friends Kymco Mongoose 90cc was showing. So my brand new bike won't charge a good battery.

Is it the stator? The regulator/rectifier?

I removed the stator and the string that covers the coil is coming off, now keep in mind this machine is new, barely been ridden. Maybe 1-2 hours on it total.

How do I test the stator, or have I already? Is is supposed to run at such a low voltage? Can somebody check their machine to see if it runs really low?

I also have my little 110cc machine, I checked it and it charges at over 16V, until you hit the lights, then it runs at 12.5-13v I assume it's the Regulator/rectifier?

I'm stumped. Anybody? There are Stators online, but at 65$ plus shipping, I'd rather not do that unless totally necessary.

[IronFist]

There is a problem with your charging system. The other bikes are correct at about 14v at 3000Rpm. There are many reasons for the drain, saddly. Trickle charge the battery would be my first suggestion. (so you have a battery when the problem's fixed) I wouldn't run the bike far until you solve your problem, my second suggestion.

Several things to try before ripping apart your stator. Though in the end the stator might be bad.

I don't know what you mean, "I removed the stator and the string that covers the coil is coming off" but others may. Don't Panic, breathe. It may take time and several opinions, but you should be able to track down the fault.

I think your machine comes with a regulator/rectifier single unit? Check those connections first. Sand the electrodes with fine sandpaper if dirty, then di-electric grease before re-attaching.

I don't know the procedure but there is a way to check the voltage coming out of the regulator/rectifier. Mine was bad and replaced and I was fine after that.

You might have a short somewhere else in the system too. Same procedure, but on every connection.

I hope it's your reg/rect, it's way cheaper and easier to replace. :wink:

[LynnEdwards]

You need to disconnect the stator from the regulator before making any useful measurements on whether the charge winding of stator is working. They affect each other so much that you can rarely tell who is at fault. When disconnected the charge winding should put out 9.5 volts AC or so while cranking (substantially higher if the quad starts). This is measured from winding end to end (it isn't tied to engine ground yet - that is done inside the regulator). It should also be about 1.2 ohms end to end. If you have the AC voltage and the ballpark resistance then the stator is fine.

Next check and double check the wiring connections, and then change the regulator.

The regulator is a shunt regulating device. As the output voltage of the stator charging system increases with engine speed the regulator crowbars the excess energy to ground, putting the charge system into current limit to maintain the 14.5 volts or so across the battery. With such a capability, a defective regulator can easily make the output of the stator look low.

[masta]

Thanks for the great reply!!

The reg/rec is the solid box correct? The stator is the windings on the left side of the motor.

So the stator produces AC voltage and the reg/rec changes it to DC correct?

So if my stator is producing 9.5V AC then it's probably my reg/rec?

[phil]

i have a post somewhere on here one of the diagrams may match yours take a look its problems like this one is why i made the post

[LynnEdwards]

Originally Posted by masta

Thanks for the great reply!!

The reg/rec is the solid box correct? The stator is the windings on the left side of the motor.

So the stator produces AC voltage and the reg/rec changes it to DC correct?

So if my stator is producing 9.5V AC then it's probably my reg/rec?

My regulator is a rectangular box with heat sink fins on it. Yes, it rectifies the AC voltage from the stator and sort of regulates the DC voltage going to the battery. I say "sort of" because it does a really poor job of it compared to what is possible with todays technology. Even for 1960's technology it is crude.

The stator is just three coils of wire that have magnets rotated past them. Two are used in the ignition system (high voltage ignition power and timing/trigger). The third is the battery charge winding. On my 8 pole stator it is actually a bunch of smaller coils all wound in series, but electrically it is the same as a single coil. What can go wrong with a coil of wire? It can be open, or maybe shorted to ground (an ohmmeter measurement will find this). More remote, but still possible, is a short between turns in the winding. Shorted turns will cause the AC output voltage to be drastically wrong. So yes, if your charge winding is producing roughly 9.5 Volts AC while cranking (and disconnected from the regulator) then the stator is OK.

Just a few posts back there is a wiring diagram of my 150cc Hensim quad. It shows the internal windings of the stator and how they are wired up. It also has the voltages and resistances of the stator windings written down. Yours is probably similar.

I have some oscilloscope waveforms of the charging system voltages where the stator is both connected and disconnected to the regulator. I will post these tonight (I have to go to work this morning). Of course you don't need an oscilloscope to troubleshoot a quad charging system, but it helps to see what the voltages look like so you can interpret what your voltmeter is telling you.

One final note: My quad's regulator also contains the current limit resistor for the automatic choke. Since the ignition system runs on its own power supply from the stator, the quad will start and run with the regulator unplugged, but if you have the same setup as mine the automatic choke won't disengage and the engine will run too rich when it warms up. Not really a big deal as long as you know about it.

[IronFist]

I hope it's your reg/rect, it's way cheaper and easier to replace.


Lynn...
If I ever got a quad, I'd be talking to you. :wink: Electicity ain't my forte. Glad you're here Lynn, have a great day!

[masta]

Wow, I am overwhelmed by your responses Lynn, very informative!!

I am so busy this week I won't have time to troubleshoot, but I am chomping at the bit to get at it, I am quite confident its' the Stator. They aren't that expensive, bust seeing as the nike is new, it sucks(no warranty on these ATV's sucks!)

There are 5 wires coming out of the stator, any idea which ones I need to check for AC voltage?

My quad has a manual choke, so no issues there, but I can't see how the machine would run with the reg.rec unplugged, or maybe I read that wrong.

[phil]

im pretty sure your wiring will be close enough to figure what you need to know with these diagrams just match and compare values there isnt a lot of diffrent ways or values used thats why i havent sent any more in and i didnt see that many people using them if you run into trouble feel free to call me or email me i may be able to talk you through it and i may have parts http://www.chinariders.net/modules.p...ghlight=#62429

[LynnEdwards]

Originally Posted by masta

There are 5 wires coming out of the stator, any idea which ones I need to check for AC voltage?

The five wires are:

1) Ignition Power (high votage, low current)
2) Ignition timing trigger pulse
3) Ground
4) One side of the battery charge winding
5) The other side of the battery charge winding

Use a process of elimination. The Ignition Power and Timing Trigger wires will disappear into the wiring harness and reappear at the CDI. Use the wire colors at the CDI to figure out which those are. Here are two common CDI's and their pin out:





Ground is usually a green wire, but verify that by looking at other known ground wires.

The two that are left are the ones you're after

Originally Posted by masta

My quad has a manual choke, so no issues there, but I can't see how the machine would run with the reg.rec unplugged, or maybe I read that wrong.

The battery, regulator, and charge winding on the stator are there only for running the lights/accessories, and turning the starter motor. That's all. The ignition system runs on a completely independant supply. Think of your lawn mower. It doesn't have a battery, regulator, or a starter (well at least mine doesn't), nor does it have head lights. Yet if you turn the engine over by hand, it starts and runs just fine. It is the same with all most all quads.

I'm not going to get the charge winding voltage waveforms that I promised posted tonight. I thought I had them up on photobucket, but they weren't there. I found them on my PC, but I need to convert them to Jpegs and upload them. I'll have them up tomorrow.

Lynn Edwards

[ejcycles]

Hi masta

What brand atv is it? I have a Coolster 110 atv in my shop that does the same thing. All the parts check out good, Stator, regulator & battery, tested against another atv brand with the exact same charging system and what I know they should test at. I have spent some time on it swapping parts "except flywheel" and it does the same thing, {too much time}. It may need a flywheel??

The lady didn't even want me to go this far and I didn't charge her for it, but it was driving me nuts so I tried to find out what was wrong. I swapped a good stator, a few regulators and tried a different battery, it won't charge past 12.8-13.0v with the lights off and it doesn't make it to 12.0 v with the lights on.

[masta]

Thanks for all the great replies guys, Wow this site has proven to be amazing in my quest to go ATv'ing on the cheap.

The machine is a YongJiang, whatever that is. It's a 110cc with the Honda engine copy.

The telltale sign something is wrong is when I run the machine without the battery and check voltage. It should be at 13-14 but shows 2.5-3. That's not going to charge anything!! If that is normal, then I have no idea how I'm going to ATV at night, unless I strap a flashlight to the thing.

[ejcycles]

masta

Close, it should show 13-16 without the battery or with a close to dead battery attached.

Granted a good charging system will charge between 13.8-14.8 volts with a low charged battery installed. With a Charged battery and the lights on it should be about the same.

The funny thing is the one I tested the customers against Charges Normally!!!

[LynnEdwards]

Measuring the voltage across the battery is an indirect way of measuring whether or not the battery is charging. A more absolute way is to measure the charge (or discharge) current directly:

Pop the main fuse out and insert your voltmeter in its place set to measure current (amps) on the 10 amps full scale setting. [Usually you have to move the voltmeter probes into different jacks on the meter to measure current.]

As a data point my quad shows the following (battery is fully charged before test):

Engine Idling, no headlights: Battery is discharging at 0.3 amps
Engine Idling, with headlights on: Battery is discharging at 3.0 amps
Engine at about 3500 RPM, no lights: Battery is charging at 3.5 amps
Engine at about 3500 RPM, with headlights on: Battery is charging at 0.2 amps.

[masta]

sweet, I will check that.

I am super busy at the moment and haven't had a chance to go take a look.

As soon as I do I will post the results.