Overcharging problem @ 23 volts

[Gunnypauly]

Hey Guys, I've got a problem that I cant figure out to save my life...Almost 3yrs ago, I got a 86 Yamaha Vmax with 18k on it. The guy I got it from said it would need a battery, because it was weak. Put a new battery in it , and every thing seemed fine for about 3 months.The battery started to show signs of getting weak. I checked the charging volts @ the batt, and saw 23volts. Did some reading , and every thing pointed to the voltage regulator. So I replaced the regulator and battery(1st) after that, charging volts were 13.1. 2012 early spring I stated riding as much as I could . June came, and on the way home from work on I-95 the bike shut off , due to the voltage regulator shorting out , and popping the mail fuse, and melting wires. Cut out the bad wiring, had to replace the voltage regulator again, put everything back together. Didnt solder the wires together, but everything looked good. 13.2 volts. A month or so after that I noticed that the battery was getting weak again (slower cranking in the morning). Checked the charging voltage, and it was read 20volts .Took it to the Yamaha dealership , and explained everything to them. About $400 later and a new(2nd) battery , they said it was loose wire connection where the stator and the regulator connect together, basically my fault is what the were saying.

Every thing seamed fine after that. That was about 4 months ago. I parked the bike for the winter. I had not started the bike in about 20 days or so . I thought it would be a good time to charger the battery, and maybe ride it up and down the street a few time. The bike wouldnt start because the the battery was to weak !!!!! So I jumped started the bike, and checked the voltage on the battery , and ITS READING 23volts

WHat the hell is going on!!! I ended up soldering the wires together where the stator\regulator connect just to make sure there are no loose connections, but that didnt fix the problem.... Is it possible that the stator is the problem, and that its burning up my voltage regulators and in return regulator is eating up my battery by overcharging it??? This will be the (3rd) battery in two yrs. Two batteries this year. Obviously, the problem is intermittent. Ive checked the voltage coming out of the stator before on the 3 wires, and they were in spec. The problem is here and now, so what do i need to check???? If anyone can help me out on this, I would really appreciate it, because im just about ready to catch the bike on fire and cook some hot dogs.. Thanks

 

[MaxMidnight]

My guess would be that the failed batteries are as a result of R/R's overcharging but this is caused by another issue.

To eliminate the alternator measure the resistance between the white wires which should be around 42 ohms.

The high voltage reading indicates that the R/R is Donald Ducked so will need replacing.

My best guess would be that it is an earthing issue causing the problem.

The early Maxii earthed the R/R through the body of the unit then via the foot-rest mount and frame to the main earth point. High resistance at any of these junctions will cause problems.

Remove the foot-rest hanger and clean the contact points; do likewise at the main earth point.
When re-assembling you could also run a separate earth wire from one of the R/R mounting bolts to the main earth.

If not already done so ensure that all connections between the R/R and battery are in good condition

 

[Rusty McNeil]

My guess would be that the failed batteries are as a result of R/R's overcharging but this is caused by another issue.

To eliminate the alternator measure the resistance between the white wires which should be around 42 ohms.

The high voltage reading indicates that the R/R is Donald Ducked so will need replacing.

My best guess would be that it is an earthing issue causing the problem.

The early Maxii earthed the R/R through the body of the unit then via the foot-rest mount and frame to the main earth point. High resistance at any of these junctions will cause problems.

Remove the foot-rest hanger and clean the contact points; do likewise at the main earth point.
When re-assembling you could also run a separate earth wire from one of the R/R mounting bolts to the main earth.

If not already done so ensure that all connections between the R/R and battery are in good condition

+1 on all this.

You can also check your stator by measuring voltage output on the three white wires.
40-55 AC Volts is about right, measured between all combinations of any two if the three. It puts out three phase AC

Likes been said already tho the over voltage is almost always due to r/r diode failure. But obviously since it keeps coming back perhaps it is a ground problem.

When the Zener diode in the r/r is trying to bleed off excess voltage it needs a path to do so, so poor/no path isn't good.

If its a late model non vmax MOSFET type r/r then the electronics are different but the principles are still the same.

 

[satariel666]

Hey Guys, I've got a problem that I cant figure out to save my life...Almost 3yrs ago, I got a 86 Yamaha Vmax with 18k on it. The guy I got it from said it would need a battery, because it was weak. Put a new battery in it , and every thing seemed fine for about 3 months.The battery started to show signs of getting weak. I checked the charging volts @ the batt, and saw 23volts. Did some reading , and every thing pointed to the voltage regulator. So I replaced the regulator and battery(1st) after that, charging volts were 13.1. 2012 early spring I stated riding as much as I could . June came, and on the way home from work on I-95 the bike shut off , due to the voltage regulator shorting out , and popping the mail fuse, and melting wires. Cut out the bad wiring, had to replace the voltage regulator again, put everything back together. Didnt solder the wires together, but everything looked good. 13.2 volts. A month or so after that I noticed that the battery was getting weak again (slower cranking in the morning). Checked the charging voltage, and it was read 20volts .Took it to the Yamaha dealership , and explained everything to them. About $400 later and a new(2nd) battery , they said it was loose wire connection where the stator and the regulator connect together, basically my fault is what the were saying.

Every thing seamed fine after that. That was about 4 months ago. I parked the bike for the winter. I had not started the bike in about 20 days or so . I thought it would be a good time to charger the battery, and maybe ride it up and down the street a few time. The bike wouldnt start because the the battery was to weak !!!!! So I jumped started the bike, and checked the voltage on the battery , and ITS READING 23volts

WHat the hell is going on!!! I ended up soldering the wires together where the stator\regulator connect just to make sure there are no loose connections, but that didnt fix the problem.... Is it possible that the stator is the problem, and that its burning up my voltage regulators and in return regulator is eating up my battery by overcharging it??? This will be the (3rd) battery in two yrs. Two batteries this year. Obviously, the problem is intermittent. Ive checked the voltage coming out of the stator before on the 3 wires, and they were in spec. The problem is here and now, so what do i need to check???? If anyone can help me out on this, I would really appreciate it, because im just about ready to catch the bike on fire and cook some hot dogs.. Thanks

Now that's funny. Lose connection will never couse an increase of voltage,
some drop of course.

Now, buy yourself a new RR first as my collgues posted. Replace or rewind the stator.
I suggest rewinding as its not that dificult - I did it myself last time.
After that battery may be still good but I doubt so be ready for having extra coin for that.

If you want to be sure about stator failure then grab an Ohm meter and messure the resistance beteween each of 3 white stator wires and engine case(find a spot with no paint).
Of course do not forget to check that ground connection on a left footpeg assambly as Steve posted.

 

[Gunnypauly]

Thanks guys for the useful info. Last time i went through this, and replaced the R/R ,I ended up getting a newer fined one for better heat dispersion. If i'm not mistake , I think it was a 2003 R/R, that had a ground wire in the wiring harness. I was told to run the extra ground wire from the R/R right to the battery, which I did, and soldered it also. Does the R/R @ the left footpeg assembly still have to be grounded to the frame, or is the addition wire coming from the R/R to the battery I ran suffice for grounding?? If not , that way just be my re occurring problem. Now in the past I did check the voltage coming out of the stator, and did check the resistance on the 3 stator wires. They all check out. So , lets assume for a second that the stator checks out again, Im guessing the only thing that can cause the R/R to burn up, is if its over heating,= lack of adequate grounding .... Does that sound about right??? Is that the only thing that can cause the R/R to burn up in this scenario?? This Monday when I get a chance, I'll check the left footpeg assembly to see if it is grounded. One last thing, my guess is, that it will show as being grounded because of the negative ground wire going to the battery from the R/R, correct me if Im wrong. The R/R is saying that's not suffice grounding... Thanks again. Will keep you posted on the progress

 

[MaxMidnight]

If it has a separate earth wire then that should be sufficient.
You should also check with a multimeter set to ohms all of the earth paths within the system and their associated cables.

The mounting of the R/R is sufficient to keep it at a safe operating temperature unless there is a bad earth whereby it will generate excess heat as it tries to regulate the voltage.

 

[wildweasel_pt]

Im not too sure the stator is in good working order. Did you measure the resistance/continuity between the 3 phases? You may have an insulation problem on the stator wiring that when dry it isolates but when splashed with motor oil will allow for continuity between phases or wires that are not supposed to be touching each other. You said its an intermittent fault so i'd check the crimps/solders at the stator as well as the 3 phase wiring. As last resort get a replacement stator for checking and find your conclusions.

 

[[email protected]]

Now that's funny. Lose connection will never couse an increase of voltage,
some drop of course.

Great point. A bad connection would cause voltage would go down, amperage up. That is why you see burnt up stator connectors. Resistance builds up due to a poor connection. Resistance causes higher amps and heat and melts the connector.

I agree that at this point, the stator should be examined again.
Keep in mind that even though the R/R is connected directly to the battery, you could still have a grounding problem if the connection between the battery and the engine/frame has a high resistance. I would definitely look into this.

 

[satariel666]

Great point. A bad connection would cause voltage would go down, amperage up. That is why you see burnt up stator connectors. Resistance builds up due to a poor connection. Resistance causes higher amps and heat and melts the connector.

I agree that at this point, the stator should be examined again.
Keep in mind that even though the R/R is connected directly to the battery, you could still have a grounding problem if the connection between the battery and the engine/frame has a high resistance. I would definitely look into this.

Appreciated Sir :biglaugh:

 

[wildweasel_pt]

Great point. A bad connection would cause voltage would go down, amperage up. That is why you see burnt up stator connectors. Resistance builds up due to a poor connection. Resistance causes higher amps and heat and melts the connector.

I agree that at this point, the stator should be examined again.
Keep in mind that even though the R/R is connected directly to the battery, you could still have a grounding problem if the connection between the battery and the engine/frame has a high resistance. I would definitely look into this.

I don't agree with what you said. for the charging circuit. The circuit is closed by the R/R ground wire to the battery directly, the only way there's the need to check the ground connections to the engine/frame is only if the R/R grounds to the frame through the casing like in the old models...

 

[Rusty McNeil]

Just thinking out loud with no diagram in front of me but when the Zener diode bleeds off over voltage doesn't it do it thoroughly the case body of the rectifier or its ground if there is one like the newer r/r's?
Just asking.

By the way, high resistance doesn't cause high amps, true that amps are dependent on voltage and resistance. Assuming voltage is same, then high resistance lower amps and vice versa.

What high resistance does, is create a voltage drop across that resistance point.

I = Amps

Power/watts = I x R, if there's no R then theres no Watts, as R goes up Watts goes up, that makes heat. Poor high resistance connections get hot and melt.

The generator just sees load, it doesn't care if its the load we want or the load we don't want like poor connections. The more you load it past its wattage capability the lower the voltage will go.

I seriously doubt a bad stator or rotor is going to melt a connection or feed high voltage to the r/r and then get turned to DC and be seen on the DC side as high voltage.
One exception is if part of the gen is lost and power consumption is so high the the remaining gen wires are asked to do more than they are capable of. This could make a ok gen wire connection get hot but it would not make high DC voltage.
I've seen a lot of bikes and older cars do the high DC voltage thing and it was always a bad regulator. Which cooks the hell out of batteries.

IF higher than normal voltage was fed from the gen to the r/r the Zener diode in the r/r should be bleeding it off. This is its normal mode anyway.....
The Zener diode is the regulator part of our r/r.

The r/r has to have a path to bleed the over voltage off to.... which was my original question or thought, it may be truly ground dependent to get rid of that bleed off but i don't have the diagram. Just thinking about things that could cause thus problem to reoccur like it is.

A bad stator is going to make lower voltages, lopsided voltages between phases, or no voltage at all on one or more of the phases due to partially or completely shorted windings or open windings which will only lessen the available power to and out of the r/r.

It's almost impossible for a gen failure to create an abnormally high voltage AC input to the r/r. It can melt a gen out put wire.

The Zener diode in the r/r is like a pressure relief valve.
Voltage is like pressure in electricity.
Amps are like flow
Watts is work achieved.
Our generators are three phase AC also.
Watts rating on a gen are what's available from the gen, actual watts consumed is entirely dependent on the system load.
You could completely cut one of the white wires from the gen and the only result on the DC side of things would be less power in watts available. Plus a little extra AC ripple on the DC side.
Checking for AC ripple on the DC side is a good troubleshooting method but you have to have a baseline for it to mean anything.

The voltage from the gen to the r/r is almost always high enough ( higher than is really needed) that the r/r is almost ALWAYS bleeding off excess voltage, its designed this way so that it can still provide adequate voltage at the lower rpm's.

If it was me the first thing I would do is ground the piss out of everything to everything, overkill isn't gonna hurt anything in this regard. And make sure the r/r positive and negative has a VERY good path straight to the battery, and that the battery has a VERY solid path to both the frame and the engine. Although that's more about charging.

I also think checking AC voltage output between the three white wires while the bike is running and the connector is unplugged is a great test of the generator ALONG with the ohm check.


The ohm check is very sensitive to temperature but regardless of temperature the values should be equal. between the three wires.

The AC voltage check should be equal numbers between all of the white wires in any combination you can think of.
The values from white wire to ground don't t mean much as the gen is either ungrounded WYE or DELTA and has no true solid reference to ground.

If you plug the gen connector in and the voltages don't stay equal to each other ( they will go down overall cause you added load when you plugged it in) I'd be looking at the r/r

I think normal AC voltage for the gen with it unplugged from the r/r is around 40-60 volts AC, I can't remember what it is plugged in and loaded.

Just as a reference my bike has the original stock components and makes a solid 13.5-14 volts at the battery at idle with two 100 watt headlight bulbs turned on. And those same stock components spin the 13:1 compression 1540 motor as well as the stock motor so I'm a pretty firm believer in the measures I've described c

 

[MaxMidnight]

Excellent posting Mr McNeil! :clapping:

If it was me the first thing I would do is ground the piss out of everything to everything, overkill isn't gonna hurt anything in this regard. And make sure the r/r positive and negative has a VERY good path straight to the battery, and that the battery has a VERY solid path to both the frame and the engine. Although that's more about charging.

Yeh, wot he said.

 

[Miles Long]

Excellent posting Mr McNeil! :clapping:

Agreed. With electrical being such a mystery to so many (myself included), it's sooooo groovy to to read detailed explanations from those that work with it professionally.
Cheers!
p.s. - when stating that you can measure the stator A.C. voltages after plugging in to the R/R, do you mean doing this with a clamp-on device, or baring wires?

 

[Rusty McNeil]

Excellent posting Mr McNeil! :clapping:

Agreed. With electrical being such a mystery to so many (myself included), it's sooooo groovy to to read detailed explanations from those that work with it professionally.
Cheers!
p.s. - when stating that you can measure the stator A.C. voltages after plugging in to the R/R, do you mean doing this with a clamp-on device, or baring wires?

Thanks,
Really I was just bored watching A&M kick the shit out of Oklahoma and felt like typing a whole lot....:rofl_200:

I would use the meter prongs and stick them down in to the connector, assuming you still have a connector.....I got rid of all mine and butt spliced, soldered/heat shrinked them so on mine I'd have to bare wires to do it......

A clamp on is for current......A normal clamp on will read AC, it takes a special "Hall Effect" clamp on to read DC......i've got one but don't think I've hardly ever used it.....