The Charging System Thread
- Thread starter ALANRIDER7
- Start date
dravnx
Well-known member
Just lost my second stator in less then a year. The first bad stator was replaced on May 2015 and 24,000 miles ago. On my way home from a romp where I rode her pretty hard, I noticed low voltage on my voltmeter and it didn't increase with RPM's. Got home, checked resistance from coil to coil and coils to ground, all good. Checked stator output at 5000 RPM and zero, zed, nada, nothing. I pulled the stator and it's burned at the usual place, the top. I thought I wouldn't have to deal with this again as I installed the series SH775 R/R last year when I replaced the stator.
Thoughts, comments, suggestions or am I just unlucky? If it matters, this is a 2012 Vstrom 650.
Thoughts, comments, suggestions or am I just unlucky? If it matters, this is a 2012 Vstrom 650.
James
Well-known member
Hey Barf!
I just finished replacing the motor in an 2001 FZ1. Motor runs great but the new motor came with an upgraded MOSFET Reg/rect. 3 wires go into the reg/rect and 2 wires come out. These 2 wires are tied directly to the battery with a 30 amp fuse in the positive wire. When I pull the red and black and test voltage with the motor running, I get 14-15 volts. When I attach the wires to the battery and start the motor I read slightly more than 12 volts at ~3000 rpm.
I am leaning towards something specific causing an excessive voltage drain. I disconnected all the connections to the front fairing (headlight, running lamps, heated grips, etc.) without much improvement. Maybe half a volt.
The remaining possibilities would be taillight/ rear turn signals. Going to test those out this evening.
Any tricks with a multi-meter to speed up isolation? I am primarily leaning on the unplug and test method.
I just finished replacing the motor in an 2001 FZ1. Motor runs great but the new motor came with an upgraded MOSFET Reg/rect. 3 wires go into the reg/rect and 2 wires come out. These 2 wires are tied directly to the battery with a 30 amp fuse in the positive wire. When I pull the red and black and test voltage with the motor running, I get 14-15 volts. When I attach the wires to the battery and start the motor I read slightly more than 12 volts at ~3000 rpm.
I am leaning towards something specific causing an excessive voltage drain. I disconnected all the connections to the front fairing (headlight, running lamps, heated grips, etc.) without much improvement. Maybe half a volt.
The remaining possibilities would be taillight/ rear turn signals. Going to test those out this evening.
Any tricks with a multi-meter to speed up isolation? I am primarily leaning on the unplug and test method.
El Feo
Rich Kid on LSD
That is probably normal. Your battery is soaking up the charge, as it is low. If it doesn't go any higher after riding on the freeway for a while, then you may have a bad battery.
mototireguy
Moto Tire Veteran
When the bike is running at low-mid rpms you should see something close to 14.4v at the battery. This is a normal charging voltage.
If the battery is low it might take a while for it to come up to this voltage.
With the bike not-running you should see 12.8v at the battery.
If the battery is low it might take a while for it to come up to this voltage.
With the bike not-running you should see 12.8v at the battery.
James
Well-known member
As a quick follow up, I ran into a situation that is hurting my brain. The FZ1 has 3 wires to each front turn signal (neutral, running, and blink). When I disconnect all 3, and measure continuity to the negative battery cable (disconnected from the battery), I get hard shorts on all 3 wires. I was expecting to have 1 short and 2 opens. Any thoughts?
Also, when I unplug a headlight socket and measure each contact (neutral, low, and high beam) I get shorts on all 3.
I am thinking there are damaged wires in the harness?
*I am an idiot. Figured out why I was getting continuity to ground. That was embarrassing. Now I am just trying to figure out why this turd isn't charging.
Also, when I unplug a headlight socket and measure each contact (neutral, low, and high beam) I get shorts on all 3.
I am thinking there are damaged wires in the harness?
*I am an idiot. Figured out why I was getting continuity to ground. That was embarrassing. Now I am just trying to figure out why this turd isn't charging.
Last edited:
James
Well-known member
Hey Barf, wanted to give an update to my charging issues. I took off the stator cover to find the flywheel had been monkeyed with and the inner threads had been stripped out. This made removing the flywheel a real chore. I ended up having to grind 3 holes on the outer wall and use a 3 jaw bearing puller. Suffice it to say, the flywheel is toast. Once the flywheel was off, I was greeted with a half burned stator.
I sent the ebay seller a message. I am not optimistic about any response. But I know what my problem is now. So, that is nice.
Thanks for all the help and fast responses here. As always, the garage has been there for me!
James
I sent the ebay seller a message. I am not optimistic about any response. But I know what my problem is now. So, that is nice.
Thanks for all the help and fast responses here. As always, the garage has been there for me!
James
dravnx
Well-known member
Charging system explained
I mined this from Stromtroopers, a Vstrom forum. It's an excellent explanation of how a motorcycle charging system works and the difference between a shunt and series regulator/rectifier.
I am responding mainly to correct the common mistaken impression, expressed above, that power not used by the loads ends up in the regulator. When I first saw that notion stated on this board, I knew it could not be right because the regulator simply did not get hot enough. (My work has resulted in assessing lots of heat dissipation concerns in electronic systems.) So I undertook the study and analysis necessary to develop the understanding outlined next.
First, a few fundamentals necessary to understand this, put in lay terms:
1. Voltage is the force exerted upon electrons (or other charged particles.) It is analogous to water pressure or the force of gravity; it tends to produce charge flow (aka "current") if such flow is allowed. It is not power or current. Just as you can have plumbing pressurized with all the faucets off, or a heavy object sitting on a shelf, there need be no current (or water moving or things falling) just because there is a force tending to move the charge (or water or things.)
2. Current is the flow of charge. It is not, by itself, power. For example, current can flow indefinitely in a superconductor loop without power being used to keep it flowing. Or, a satellite can keep falling around the earth, in a stable orbit, without power used to sustain its motion, (if it is well out of the atmosphere.)
3. Electrical power is the product of voltage and current. It is usually stated in units of Watts, which is the product of voltage (in units of Volts) and current (in units of Amperes, often called "Amps".)
4. Current or voltage can be AC, which means regularly alternating in direction, or DC, which means steadily in one direction. The motorcycle loads need DC voltage and current. The battery provides DC voltage, and is charged by DC current or discharged by DC current.
The motorcycle magneto (which is the combination of the stator and the rotating permanent magnets enclosing it) generates a set of 3 AC voltages proportional to engine speed. The magneto output current, collectively among its 3 windings, is limited to about 28 Amps at all engine speeds. (The limiting mechanism is the stator inductance, whose impedance increases directly with frequency which is proportional to engine speed.)
If the magneto output is left open, so that no current can flow, there is negligible power delivered through the stator. The product of voltage and current is zero because the current is very close to zero.
If the magneto output is shorted, so that no voltage can appear across the stator terminals, the stator ouput power is zero. The product of output voltage and current is zero because the output voltage is very close to zero. If the stator windings were made with superconductors, the magneto with shorted output would convert no mechanical power to electrical power. Average torque applied to its rotor would be zero.
Unfortunately, the stator is not made with superconductors; the windings are made with copper and have some resistance. It is about 0.1 Ohms per winding, meaning that about 0.1 Volts must be applied to each winding just to get an Ampere of current to flow. Because of this resistance, the 28 Amperes of current flow from the stator dissipates over 60 Watts in the copper windings regardless of whether the output is shorted or delivering useful power to the loads. It is that 60+ Watt power dissipation which stresses the stator on stock bikes.
The stock, shunt regulator (sort of) shorts (or "shunts") the stator output as necessary to keep excessive power from reaching the 12V DC bus and destroying the battery and (most of) the loads. While that "shorting" occurs, about 50 Watts is dissipated in the regulator because it does not truly short the stator output at zero Volts. It uses diodes to convert the AC stator output to DC, and those drop a couple of Volts when conducting current. This 50 Watts is also dissipated when the regulator is not shunting but passing stator current to the DC bus. So the stator resistance and regulator are always consuming over 100 Watts when the stock bike runs.
The series regulator, instead of shunting the stator output to avoid excess DC bus power, blocks current flow between the stator and the DC bus. During this blocking, negligible power is dissipated in the stator or in the regulator's AC-to-DC conversion devices. So, for a typical bike load of a couple hundred Watts, the stator dissipation is reduced by about half. Likewise, the regulator dissipation is reduced. This reduced wasted power will translate to a small gas mileage improvement which you will be able to see if you measure it carefully before and after replacing the shunt regulator with a series one.
The bottom line here is: While there is 400W available from the magneto, that much power is not consumed when the loads do not take 400W. A significant fraction of the 400 available Watts, nearly a third, is wasted and converted to heat in the shunt-regulated system at all times when riding. (It drops a bit when idling.)
To answer the thread title's question: There is very little difference in regulator or stator dissipation, with the shunt-regulated system, between the stock load, a load closer to 400W (heated gear, etc.), or a load reduced by use of LED headlights. However, with the series-regulated system, regulator and stator dissipation are substantially reduced when the loads consume substantially less than 400W. (And conversely, when the loads take all of the available power, the series regulator yields no significant reduction in stator or regulator dissipation.)
I mined this from Stromtroopers, a Vstrom forum. It's an excellent explanation of how a motorcycle charging system works and the difference between a shunt and series regulator/rectifier.
I am responding mainly to correct the common mistaken impression, expressed above, that power not used by the loads ends up in the regulator. When I first saw that notion stated on this board, I knew it could not be right because the regulator simply did not get hot enough. (My work has resulted in assessing lots of heat dissipation concerns in electronic systems.) So I undertook the study and analysis necessary to develop the understanding outlined next.
First, a few fundamentals necessary to understand this, put in lay terms:
1. Voltage is the force exerted upon electrons (or other charged particles.) It is analogous to water pressure or the force of gravity; it tends to produce charge flow (aka "current") if such flow is allowed. It is not power or current. Just as you can have plumbing pressurized with all the faucets off, or a heavy object sitting on a shelf, there need be no current (or water moving or things falling) just because there is a force tending to move the charge (or water or things.)
2. Current is the flow of charge. It is not, by itself, power. For example, current can flow indefinitely in a superconductor loop without power being used to keep it flowing. Or, a satellite can keep falling around the earth, in a stable orbit, without power used to sustain its motion, (if it is well out of the atmosphere.)
3. Electrical power is the product of voltage and current. It is usually stated in units of Watts, which is the product of voltage (in units of Volts) and current (in units of Amperes, often called "Amps".)
4. Current or voltage can be AC, which means regularly alternating in direction, or DC, which means steadily in one direction. The motorcycle loads need DC voltage and current. The battery provides DC voltage, and is charged by DC current or discharged by DC current.
The motorcycle magneto (which is the combination of the stator and the rotating permanent magnets enclosing it) generates a set of 3 AC voltages proportional to engine speed. The magneto output current, collectively among its 3 windings, is limited to about 28 Amps at all engine speeds. (The limiting mechanism is the stator inductance, whose impedance increases directly with frequency which is proportional to engine speed.)
If the magneto output is left open, so that no current can flow, there is negligible power delivered through the stator. The product of voltage and current is zero because the current is very close to zero.
If the magneto output is shorted, so that no voltage can appear across the stator terminals, the stator ouput power is zero. The product of output voltage and current is zero because the output voltage is very close to zero. If the stator windings were made with superconductors, the magneto with shorted output would convert no mechanical power to electrical power. Average torque applied to its rotor would be zero.
Unfortunately, the stator is not made with superconductors; the windings are made with copper and have some resistance. It is about 0.1 Ohms per winding, meaning that about 0.1 Volts must be applied to each winding just to get an Ampere of current to flow. Because of this resistance, the 28 Amperes of current flow from the stator dissipates over 60 Watts in the copper windings regardless of whether the output is shorted or delivering useful power to the loads. It is that 60+ Watt power dissipation which stresses the stator on stock bikes.
The stock, shunt regulator (sort of) shorts (or "shunts") the stator output as necessary to keep excessive power from reaching the 12V DC bus and destroying the battery and (most of) the loads. While that "shorting" occurs, about 50 Watts is dissipated in the regulator because it does not truly short the stator output at zero Volts. It uses diodes to convert the AC stator output to DC, and those drop a couple of Volts when conducting current. This 50 Watts is also dissipated when the regulator is not shunting but passing stator current to the DC bus. So the stator resistance and regulator are always consuming over 100 Watts when the stock bike runs.
The series regulator, instead of shunting the stator output to avoid excess DC bus power, blocks current flow between the stator and the DC bus. During this blocking, negligible power is dissipated in the stator or in the regulator's AC-to-DC conversion devices. So, for a typical bike load of a couple hundred Watts, the stator dissipation is reduced by about half. Likewise, the regulator dissipation is reduced. This reduced wasted power will translate to a small gas mileage improvement which you will be able to see if you measure it carefully before and after replacing the shunt regulator with a series one.
The bottom line here is: While there is 400W available from the magneto, that much power is not consumed when the loads do not take 400W. A significant fraction of the 400 available Watts, nearly a third, is wasted and converted to heat in the shunt-regulated system at all times when riding. (It drops a bit when idling.)
To answer the thread title's question: There is very little difference in regulator or stator dissipation, with the shunt-regulated system, between the stock load, a load closer to 400W (heated gear, etc.), or a load reduced by use of LED headlights. However, with the series-regulated system, regulator and stator dissipation are substantially reduced when the loads consume substantially less than 400W. (And conversely, when the loads take all of the available power, the series regulator yields no significant reduction in stator or regulator dissipation.)