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DaveB

Just Installed a Compufire Series Regulator

186 posts in this topic

I just installed a Compu-fire 55402 series regulator; I bought it from Chrome-Addiction.com for $173.

The unit is a little smaller than the standard Honda R&R but the mounting holes line up nicely so installation was easy. I just cut off the stator connector and lengthen the wires then connected them to the new regulator using a connector block. The unit came with 2 long and very beefy power output wires which I connected directly to the battery via the 40 amp fuse that it came with. This avoids using the old cables and connectors that everyone here on this site seems to replace with a VFRness.

The regulator gave 14.25 volts at the battery and was supplying 15 amps to run the bike and charge the battery i.e. much less that the 40 amps that is continuously supplied by original shunt unit most of which is dumped to ground.

The major benefit of the series regulator is that the power supplied is typically half that of the standard unit as it doesn’t regulate by dumping excess power to ground. So I don’t expect to burn up regulators and stators on regular basis as many people here seem to. The regulator is rated at 40 amps which gives it has plenty of reserve power for more accessories.

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Thanks for posting up on your install.

There will be a lot of interest in your long term experience with it. My GSXR 750 R/R on my '97 has been working great for almost 3 years now, but if it dies I'll probably go with the Compufire.

Edited by rangemaster

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Just curious, with headlights on low, and metering the battery, how does the voltage change as you raise thottle to around 5000 rpm? Then try on high

You can see the shuting of voltage with stock set up, atleast till the high beams generate a big load,

Edited by spud786

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Just curious, with headlights on low, and metering the battery, how does the voltage change as you raise thottle to around 5000 rpm? Then try on high

You can see the shuting of voltage with stock set up, at least till the high beams generate a big load,

Increasing the RPM from 1200 to 5000 rpm caused the battery voltage to drop from 14.25 to 14.15 it made no difference whether the high beams were on. At idle putting on the high beams again dropped the voltage to 14.15. So it seems to regulate to 14.15 to 14.25 volts.

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I just installed a Compu-fire 55402 series regulator; I bought it from Chrome-Addiction.com for $173.

The unit is a little smaller than the standard Honda R&R but the mounting holes line up nicely so installation was easy. I just cut off the stator connector and lengthen the wires then connected them to the new regulator using a connector block. The unit came with 2 long and very beefy power output wires which I connected directly to the battery via the 40 amp fuse that it came with. This avoids using the old cables and connectors that everyone here on this site seems to replace with a VFRness.

The regulator gave 14.25 volts at the battery and was supplying 15 amps to run the bike and charge the battery i.e. much less that the 40 amps that is continuously supplied by original shunt unit most of which is dumped to ground.

The major benefit of the series regulator is that the power supplied is typically half that of the standard unit as it doesnt regulate by dumping excess power to ground. So I dont expect to burn up regulators and stators on regular basis as many people here seem to. The regulator is rated at 40 amps which gives it has plenty of reserve power for more accessories.

Could you post some pics of the install? This is on my to do list for my '98 electrical cleanup.

-- Let us how know this works out - you may be the first CF R/R on a VFR.

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I just installed a Compu-fire 55402 series regulator; I bought it from Chrome-Addiction.com for $173.

The unit is a little smaller than the standard Honda R&R but the mounting holes line up nicely so installation was easy. I just cut off the stator connector and lengthen the wires then connected them to the new regulator using a connector block. The unit came with 2 long and very beefy power output wires which I connected directly to the battery via the 40 amp fuse that it came with. This avoids using the old cables and connectors that everyone here on this site seems to replace with a VFRness.

The regulator gave 14.25 volts at the battery and was supplying 15 amps to run the bike and charge the battery i.e. much less that the 40 amps that is continuously supplied by original shunt unit most of which is dumped to ground.

The major benefit of the series regulator is that the power supplied is typically half that of the standard unit as it doesn’t regulate by dumping excess power to ground. So I don’t expect to burn up regulators and stators on regular basis as many people here seem to. The regulator is rated at 40 amps which gives it has plenty of reserve power for more accessories.

Could you post some pics of the install? This is on my to do list for my '98 electrical cleanup.

-- Let us how know this works out - you may be the first CF R/R on a VFR.

Here are a few pics sorry i didn't photograph

the unit off the bike

post-20702-0-15308300-1303574516_thumb.j

post-20702-0-99391200-1303574803_thumb.j

The old Honda unit

post-20702-0-61086200-1303574566_thumb.j

Lengthen stator wires

post-20702-0-49614700-1303574640_thumb.j

Battery connection with fuse

post-20702-0-27750000-1303574866_thumb.j

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Increasing the RPM from 1200 to 5000 rpm caused the battery voltage to drop from 14.25 to 14.15 it made no difference whether the high beams were on. At idle putting on the high beams again dropped the voltage to 14.15. So it seems to regulate to 14.15 to 14.25 volts.

This sounds like 14V+ at 1200 rpm idle with high beams on, which seems unlikely to me. Can you double-check that?

My test with factory components:

(FYI - You may need to cut the volume down...)

Edited by pserve

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I just received a new MOSFET regulator / rectifier from "wiremybike.com". Hope to get around to the install in the next day or two. My factory unit is still working fine at 40,000 miles, but I am hitting the road for a few days in May and thought it would be a good time to do the upgrade in order to avoid getting stranded.

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Just curious, with headlights on low, and metering the battery, how does the voltage change as you raise thottle to around 5000 rpm? Then try on high

You can see the shuting of voltage with stock set up, at least till the high beams generate a big load,

Increasing the RPM from 1200 to 5000 rpm caused the battery voltage to drop from 14.25 to 14.15 it made no difference whether the high beams were on. At idle putting on the high beams again dropped the voltage to 14.15. So it seems to regulate to 14.15 to 14.25 volts.

Interesting Notes and results. If these really are the answer to increased stator life, that would be nice. The Voltage seem to be running lower than a stock 6th gen, so I would expect higher current levels, under load.

But it comes down to Stator life, If people consistantly getiing more than 60,000 mile on stators, that would be a really good sign,

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Increasing the RPM from 1200 to 5000 rpm caused the battery voltage to drop from 14.25 to 14.15 it made no difference whether the high beams were on. At idle putting on the high beams again dropped the voltage to 14.15. So it seems to regulate to 14.15 to 14.25 volts.

This sounds like 14V+ at 1200 rpm idle with high beams on, which seems unlikely to me. Can you double-check that?

My test with factory components:

(FYI - You may need to cut the volume down...)

According to its specs this R&R is set to regulate to 14.25 volts which may be a little less than the stock Honda unit. On their web site Compu-fire claim their 3 phase charging system will give 25 amps at idle and 40 amps above 2800 rpm this is with their stator and is of course designed for use on a Harley.

I got 14.15 volts at 1200 rpm idle with the high beams on. So it works for me !

I have just done 120 miles with no issues I'll let you know how I get on in a few 1000 miles more.

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I got 14.15 volts at 1200 rpm idle with the high beams on. So it works for me !

Fair enough. I don't know how it can manage that, but since it can, I'll bet they will sell a lot of them.

Thanks for the clarification. :fing02:

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I just installed a Compu-fire 55402 series regulator; I bought it from Chrome-Addiction.com for $173.

The unit is a little smaller than the standard Honda R&R but the mounting holes line up nicely so installation was easy. I just cut off the stator connector and lengthen the wires then connected them to the new regulator using a connector block. The unit came with 2 long and very beefy power output wires which I connected directly to the battery via the 40 amp fuse that it came with. This avoids using the old cables and connectors that everyone here on this site seems to replace with a VFRness.

The regulator gave 14.25 volts at the battery and was supplying 15 amps to run the bike and charge the battery i.e. much less that the 40 amps that is continuously supplied by original shunt unit most of which is dumped to ground.

The major benefit of the series regulator is that the power supplied is typically half that of the standard unit as it doesn’t regulate by dumping excess power to ground. So I don’t expect to burn up regulators and stators on regular basis as many people here seem to. The regulator is rated at 40 amps which gives it has plenty of reserve power for more accessories.

1. The compufire unit has 5 wires? (3 stator and 2 output wires) For some reason, I thought the compufire came with MORE wires that VFRs couldn't use, unique to the Harley application, etc, so I'm trying to make sure you didn't NOT use any provided wires, and that you DID use all provided wires. From the below pic of the compufire, it appears to have 3 smaller wires in the middle and one larger wire on each end of the unit. Are both of the larger wires output wires?

2. "The unit came with 2 long and very beefy power output wires which I connected directly to the battery . . . ." You hooked both of the larger wires to the battery positive terminal? How did you connect them to the battery? Tie them together and then put one connector on the positive terminal? Two separate connectors to the positive terminal? According to this post, http://www.triumphrat.net/speed-triple-forum/152623-compufire-55402-regulator-install-information.html the two non-stator wires consist of one output and one ground wire.

3. Your last pic appears to show an added wire to the negative terminal. Is that just an extra ground? Or is that one of the wires from the compufire?

4. What about heat from the compufire? Same as stock? Less?

Thanks for being the guinea pig on this mod!

post-5928-0-67998000-1303677163_thumb.jp

Edited by Misspent Youth

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I just installed a Compu-fire 55402 series regulator; I bought it from Chrome-Addiction.com for $173.

The unit is a little smaller than the standard Honda R&R but the mounting holes line up nicely so installation was easy. I just cut off the stator connector and lengthen the wires then connected them to the new regulator using a connector block. The unit came with 2 long and very beefy power output wires which I connected directly to the battery via the 40 amp fuse that it came with. This avoids using the old cables and connectors that everyone here on this site seems to replace with a VFRness.

The regulator gave 14.25 volts at the battery and was supplying 15 amps to run the bike and charge the battery i.e. much less that the 40 amps that is continuously supplied by original shunt unit most of which is dumped to ground.

The major benefit of the series regulator is that the power supplied is typically half that of the standard unit as it doesn’t regulate by dumping excess power to ground. So I don’t expect to burn up regulators and stators on regular basis as many people here seem to. The regulator is rated at 40 amps which gives it has plenty of reserve power for more accessories.

1. The compufire unit has 5 wires? (3 stator and 2 output wires) For some reason, I thought the compufire came with MORE wires that VFRs couldn't use, unique to the Harley application, etc, so I'm trying to make sure you didn't NOT use any provided wires, and that you DID use all provided wires. From the below pic of the compufire, it appears to have 3 smaller wires in the middle and one larger wire on each end of the unit. Are both of the larger wires output wires?

Yes the longer wires are the power output. The stator wires are the ones terminated by the 3 terminal connector . I cut this connector off also cut the VFR stator connector off and soldered longer wires on insulated with heat shrink sleeving then used a connector block to connect the regulator to the bike stator. I could have used 2 connector blocks instead of soldering or soldered both ends but then replacement would have been harder.

2. "The unit came with 2 long and very beefy power output wires which I connected directly to the battery . . . ." You hooked both of the larger wires to the battery positive terminal? How did you connect them to the battery? Tie them together and then put one connector on the positive terminal? Two separate connectors to the positive terminal? According to this post, http://www.triumphrat.net/speed-triple-forum/152623-compufire-55402-regulator-install-information.html the two non-stator wires consist of one output and one ground wire.

The power output i.e. positive and negative (ground); I wired directly to the battery, the positive output to the positive battery terminal via a fuse that they supplied and the ground to the negative terminal. I just used the eyelets already on the cables and put them under the battery connector bolts you can see them in the pic. I also wanted to connect my trickle charger so I soldered on additional wires to the R&R cables rather than try to stuff more eyelets on the battery connectors that's what you can sees in the pic. Using their beefy wires directly to the battery means you don't need a VFRness to beef up the stock wiring.

i initially tried wiring to the connector that the original R&R used for power output but I lost 0.5 volt through the Honda wiring and connectors. It was actually easier and a lot better electrically wiring directly to the battery.

3. Your last pic appears to show an added wire to the negative terminal. Is that just an extra ground? Or is that one of the wires from the compufire?

No that was me adding a connection for my trickle charger.

4. What about heat from the compufire? Same as stock? Less?

Testing stationary in my garage it got a little hot on the road it runs very cool due to the air flow round the heat sink and that it dissipates much less power than the stock shunt R&R. I don't know what the heat is like on the Honda unit but have heard it runs very hot.

Thanks for being the guinea pig on this mod!

It's my pleasure. I've read so much bad stuff about the R&R, wiring, connectors and stator failures. As an electrical engineer I am convinced this is the solution to all this crappy electrical design and it is really easy to fit and as you don't need to replace the wiring and connectors with the VFRness is not that expensive.

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]It's my pleasure. I've read so much bad stuff about the R&R, wiring, connectors and stator failures. As an electrical engineer I am convinced this is the solution to all this crappy electrical design and it is really easy to fit and as you don't need to replace the wiring and connectors with the VFRness is not that expensive.

Wow, an electrical engineer who's installed a compu-fire - I've died and gone to VFR/electrical heaven! I promise not to abuse you, and I think you may have answered this before (I recall being confused by someone's answer to a similar question, but this seems familiar), but I remain confused about the "how" behind the compu-fire product. (All of my "understandings" are subject to correction) I understand the stock stator acts as a "constantly on" generator that feeds electricity (pardon my likely incorrect use of certain terms, here) to the stock r/r which acts as the brain that somehow considers battery/bike voltage needs and decides whether to shunt the produced electricity to the battery, or to ground. I understand it's this shunting to ground process that creates the heat within the r/r.

When I look at the compu-fire site (http://www.compufire.com/harley-main.html), I see: "When the battery reaches full charge, the stator output is switched off by the regulator."

So the stock r/r lets the stator keep running, but shunts the unneeded electricity to ground (creating heat), and the compu-fire somehow "switches off" the stator's output.

1. That sounds like the compu-fire breaks the connection from the stator to ground within the compu-fire unit - is that correct?

2. If something like that is happening, but the stator is still subject to the spinning magnetic flywheel and generating electricity, where does that electricity go? Or, is there NO electricity being produced if the stator's not connected up at the r/r?

3. According to the guru on the Triumph site, one should go to a compu-fire if one is burning up stators because the compu-fire is easier on stators. If the electrical connection is broken in the compu-fire, but the electricity is still being produced by the spinning flywheel/stator, how is that easier on the stator? Seems to be the same, to me.

I'm working to understand these issue and much appreciate your time and understanding. It's not easy digesting this technical stuff without sufficient training. I hope my questions are clear enough, but let me know if I need to clarify anything. Thanks again.

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I'm wondering if this unit has been examined by Tightwad yet. It sounds nice.

Also, my bike with a fresh stator and cleaned/greased connectors, and the stock R/R didn't put out more than 14.25 volts from idle to 5,000 RPM so I'm not sure what all that means. Probably means I'll get stranded somewhere fantastic again... I sure love me some Honda electrics.

In reply to Mr. Misspent; I believe you have the right idea about the Compufire R/R breaking connection to ground as seen by the stator. No ground, no circuit, no power production. Spinning a magnet around a piece of wire that electrically floating will not create amperage and the stator should live a little longer and average a cooler operating temp. And with MOSFET switching (I assume the Compufire unit uses MOSFETs, I haven't read about it directly) it should live a cooler and happier life as well.

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Today I installed the new MOSFET R/R. Compared to the OEM unit, this one is a bit smaller, and does not have the monitor wire.

Install could not have been much easier as this unit comes with the OEM Honda connectors and is basically plug & go.

With the new unit, I am getting 13.4 volts at idle and 14.4 at 5000 rpm. What surprised me was that when switching on the high beams at 5000 rpm, the voltage went up to 14.7. I expected switching on the high beams to pull the voltage down just a bit.

By the way.....I purchased the R/R for 145 bucks at "wiremybike.com".. Thanks Tightwad!

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]It's my pleasure. I've read so much bad stuff about the R&R, wiring, connectors and stator failures. As an electrical engineer I am convinced this is the solution to all this crappy electrical design and it is really easy to fit and as you don't need to replace the wiring and connectors with the VFRness is not that expensive.

Wow, an electrical engineer who's installed a compu-fire - I've died and gone to VFR/electrical heaven! I promise not to abuse you, and I think you may have answered this before (I recall being confused by someone's answer to a similar question, but this seems familiar), but I remain confused about the "how" behind the compu-fire product. (All of my "understandings" are subject to correction) I understand the stock stator acts as a "constantly on" generator that feeds electricity (pardon my likely incorrect use of certain terms, here) to the stock r/r which acts as the brain that somehow considers battery/bike voltage needs and decides whether to shunt the produced electricity to the battery, or to ground. I understand it's this shunting to ground process that creates the heat within the r/r.

When I look at the compu-fire site (http://www.compufire.com/harley-main.html), I see: "When the battery reaches full charge, the stator output is switched off by the regulator."

So the stock r/r lets the stator keep running, but shunts the unneeded electricity to ground (creating heat), and the compu-fire somehow "switches off" the stator's output.

1. That sounds like the compu-fire breaks the connection from the stator to ground within the compu-fire unit - is that correct?

2. If something like that is happening, but the stator is still subject to the spinning magnetic flywheel and generating electricity, where does that electricity go? Or, is there NO electricity being produced if the stator's not connected up at the r/r?

3. According to the guru on the Triumph site, one should go to a compu-fire if one is burning up stators because the compu-fire is easier on stators. If the electrical connection is broken in the compu-fire, but the electricity is still being produced by the spinning flywheel/stator, how is that easier on the stator? Seems to be the same, to me.

I'm working to understand these issue and much appreciate your time and understanding. It's not easy digesting this technical stuff without sufficient training. I hope my questions are clear enough, but let me know if I need to clarify anything. Thanks again.

I know it is confusing.

The generator spins magnets around coils to generate electricity. If you don't put an electrical load on the coils there is no electricity generated and no more mechanical energy is required to spin the magnets , as you load the circuit with more lights etc. then a bigger mechanical load is put on the engine due to the magnetic interaction. As you use the electricity i.e connect lights etc to it it puts a mechanical load on the engine and slows it down. It you do not use that electricity .i.e don't connect the generator output to anything then it puts no mechanical load load on the engine. It is like your electric outlets at home if you don't plug stuff in then you don't pay for any electricity used, but the generators are still running they just don't need as much fuel as they aren't generating as much energy unless you and everyone else has stuff plugged in using power.

So spinning magnets in front of stator coils creates the potential to generate electrical power as you load up those coils with electrical circuits e.g. lamps then power is generated and used the more power used the greater the mechanical load put on the engine.

Think of a charged battery if you don't connect anything it does not deliver any power or get discharged but as you connect more lamps it gives more power that power was always there but only used when you connect stuff to it. The chemical activity that generates the power only happens when you connect stuff to the battery, the same is true of a generator. As power is used it requires mechanical effort so a generator only generates the power that you demand of it.

An important point is that a generator has a maximum amount of power it can generate so it you ask for to much power the output voltage will sag and reduced the current. A shunt regulator works by putting a big load to ground to force the output voltage to remain at 14.5 volts.

So the way a shunt regulator works is to overload the stator so it can only produce 14.5 volts which happens when it is generating 40 amps. So if the bike needs 15 amps then 25 amps are shunted to ground or just wasted. If the bike needs 20 amps then only 20 amps are wasted to ground. The regulator basically absorbs any excess current to ground keeping the generator giving 40 amps and 14.5 volts. Which is why we keep blowing stators as they always run at maximum power of 40 amps which also generates a lot of heat.

A series regulator works by reducing the voltage from the stator (it effectively puts variable series resistance between the stator and the bike) so that that the output voltage is reduced to 14.25 volts no matter what the current drawn by the bike is.

The series regulator reduces the generator output voltage to 14.25 volts at what ever current the bike is demanding so if the bike only needs 15 amps then the stator only generates 15 amps remember the stator generates 60 volts unloaded at 5000 rpm the shunt regulator overloads the stator to reduce the voltage the series regulator limits the output voltage by limiting the current supplied and reducing the voltage not overloading the generator.

Conclusion a shunt regulator always takes 40 amps from the stator running it at max power and so it eventually burns out whereas a series regulator only allows the current required by the bike to be drawn from the stator which is 15 amps with no accessorize so the stator only generates 15 amps of electricity and the associated heat and so it lasts a lot longer as it is working half as hard as with a shunt regulator where it generate 40 amps worth of heat.

I hope this makes sense.

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]It's my pleasure. I've read so much bad stuff about the R&R, wiring, connectors and stator failures. As an electrical engineer I am convinced this is the solution to all this crappy electrical design and it is really easy to fit and as you don't need to replace the wiring and connectors with the VFRness is not that expensive.

Wow, an electrical engineer who's installed a compu-fire - I've died and gone to VFR/electrical heaven! I promise not to abuse you, and I think you may have answered this before (I recall being confused by someone's answer to a similar question, but this seems familiar), but I remain confused about the "how" behind the compu-fire product. (All of my "understandings" are subject to correction) I understand the stock stator acts as a "constantly on" generator that feeds electricity (pardon my likely incorrect use of certain terms, here) to the stock r/r which acts as the brain that somehow considers battery/bike voltage needs and decides whether to shunt the produced electricity to the battery, or to ground. I understand it's this shunting to ground process that creates the heat within the r/r.

When I look at the compu-fire site (http://www.compufire...arley-main.html), I see: "When the battery reaches full charge, the stator output is switched off by the regulator."

So the stock r/r lets the stator keep running, but shunts the unneeded electricity to ground (creating heat), and the compu-fire somehow "switches off" the stator's output.

1. That sounds like the compu-fire breaks the connection from the stator to ground within the compu-fire unit - is that correct?

2. If something like that is happening, but the stator is still subject to the spinning magnetic flywheel and generating electricity, where does that electricity go? Or, is there NO electricity being produced if the stator's not connected up at the r/r?

3. According to the guru on the Triumph site, one should go to a compu-fire if one is burning up stators because the compu-fire is easier on stators. If the electrical connection is broken in the compu-fire, but the electricity is still being produced by the spinning flywheel/stator, how is that easier on the stator? Seems to be the same, to me.

I'm working to understand these issue and much appreciate your time and understanding. It's not easy digesting this technical stuff without sufficient training. I hope my questions are clear enough, but let me know if I need to clarify anything. Thanks again.

I know it is confusing.

The generator spins magnets around coils to generate electricity. If you don't put an electrical load on the coils there is no electricity generated and no more mechanical energy is required to spin the magnets , as you load the circuit with more lights etc. then a bigger mechanical load is put on the engine due to the magnetic interaction. As you use the electricity i.e connect lights etc to it it puts a mechanical load on the engine and slows it down. It you do not use that electricity .i.e don't connect the generator output to anything then it puts no mechanical load load on the engine. It is like your electric outlets at home if you don't plug stuff in then you don't pay for any electricity used, but the generators are still running they just don't need as much fuel as they aren't generating as much energy unless you and everyone else has stuff plugged in using power.

So spinning magnets in front of stator coils creates the potential to generate electrical power as you load up those coils with electrical circuits e.g. lamps then power is generated and used the more power used the greater the mechanical load put on the engine.

Think of a charged battery if you don't connect anything it does not deliver any power or get discharged but as you connect more lamps it gives more power that power was always there but only used when you connect stuff to it. The chemical activity that generates the power only happens when you connect stuff to the battery, the same is true of a generator. As power is used it requires mechanical effort so a generator only generates the power that you demand of it.

An important point is that a generator has a maximum amount of power it can generate so it you ask for to much power the output voltage will sag and reduced the current. A shunt regulator works by putting a big load to ground to force the output voltage to remain at 14.5 volts.

So the way a shunt regulator works is to overload the stator so it can only produce 14.5 volts which happens when it is generating 40 amps. So if the bike needs 15 amps then 25 amps are shunted to ground or just wasted. If the bike needs 20 amps then only 20 amps are wasted to ground. The regulator basically absorbs any excess current to ground keeping the generator giving 40 amps and 14.5 volts. Which is why we keep blowing stators as they always run at maximum power of 40 amps which also generates a lot of heat.

A series regulator works by reducing the voltage from the stator (it effectively puts variable series resistance between the stator and the bike) so that that the output voltage is reduced to 14.25 volts no matter what the current drawn by the bike is.

The series regulator reduces the generator output voltage to 14.25 volts at what ever current the bike is demanding so if the bike only needs 15 amps then the stator only generates 15 amps remember the stator generates 60 volts unloaded at 5000 rpm the shunt regulator overloads the stator to reduce the voltage the series regulator limits the output voltage by limiting the current supplied and reducing the voltage not overloading the generator.

Conclusion a shunt regulator always takes 40 amps from the stator running it at max power and so it eventually burns out whereas a series regulator only allows the current required by the bike to be drawn from the stator which is 15 amps with no accessorize so the stator only generates 15 amps of electricity and the associated heat and so it last a lot longer as it is working half as hard as with a shunt regulator where it generate 40 amps worth of heat.

I hope this makes sense.

Very nice explanation. Even a social scientist could understand it. :cool:

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Good job Dave, thanks :fing02:

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Today I installed the new MOSFET R/R. Compared to the OEM unit, this one is a bit smaller, and does not have the monitor wire.

. What surprised me was that when switching on the high beams at 5000 rpm, the voltage went up to 14.7. I expected switching on the high beams to pull the voltage down just a bit.

Thats normal for the oem RR too, if its working correctly

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Conclusion a shunt regulator always takes 40 amps from the stator running it at max power and so it eventually burns out whereas a series regulator only allows the current required by the bike to be drawn from the stator which is 15 amps with no accessorize so the stator only generates 15 amps of electricity and the associated heat and so it lasts a lot longer as it is working half as hard as with a shunt regulator where it generate 40 amps worth of heat.

I hope this makes sense.

"A series regulator works by reducing the voltage from the stator (it effectively puts variable series resistance between the stator and the bike) so that that the output voltage is reduced to 14.25 volts no matter what the current drawn by the bike is."

So the series regulator doesn't switch off the stator's production when the bike has enough electricity, it regulates the stator's output according to the perceived needs of the bike. I think I get it now. Thanks for the comprehensive explanation. I look forward to any periodic updates you have on your compu-fire experience.

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I am happy to see another solution to an ever existing problem. Hopefully the Compufire does as well as claimed. They seem to be good on Stators, but then the Honda issue is more often the wiring and the R/R, although stators can and do fail as well. It is hard to know in those situations which went first. So far the R/R’s from Ricks (MOSFET series) are holding up well also.

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]It's my pleasure. I've read so much bad stuff about the R&R, wiring, connectors and stator failures. As an electrical engineer I am convinced this is the solution to all this crappy electrical design and it is really easy to fit and as you don't need to replace the wiring and connectors with the VFRness is not that expensive.

Wow, an electrical engineer who's installed a compu-fire - I've died and gone to VFR/electrical heaven! I promise not to abuse you, and I think you may have answered this before (I recall being confused by someone's answer to a similar question, but this seems familiar), but I remain confused about the "how" behind the compu-fire product. (All of my "understandings" are subject to correction) I understand the stock stator acts as a "constantly on" generator that feeds electricity (pardon my likely incorrect use of certain terms, here) to the stock r/r which acts as the brain that somehow considers battery/bike voltage needs and decides whether to shunt the produced electricity to the battery, or to ground. I understand it's this shunting to ground process that creates the heat within the r/r.

When I look at the compu-fire site (http://www.compufire.com/harley-main.html), I see: "When the battery reaches full charge, the stator output is switched off by the regulator."

So the stock r/r lets the stator keep running, but shunts the unneeded electricity to ground (creating heat), and the compu-fire somehow "switches off" the stator's output.

1. That sounds like the compu-fire breaks the connection from the stator to ground within the compu-fire unit - is that correct?

2. If something like that is happening, but the stator is still subject to the spinning magnetic flywheel and generating electricity, where does that electricity go? Or, is there NO electricity being produced if the stator's not connected up at the r/r?

3. According to the guru on the Triumph site, one should go to a compu-fire if one is burning up stators because the compu-fire is easier on stators. If the electrical connection is broken in the compu-fire, but the electricity is still being produced by the spinning flywheel/stator, how is that easier on the stator? Seems to be the same, to me.

I'm working to understand these issue and much appreciate your time and understanding. It's not easy digesting this technical stuff without sufficient training. I hope my questions are clear enough, but let me know if I need to clarify anything. Thanks again.

I know it is confusing.

The generator spins magnets around coils to generate electricity. If you don't put an electrical load on the coils there is no electricity generated and no more mechanical energy is required to spin the magnets , as you load the circuit with more lights etc. then a bigger mechanical load is put on the engine due to the magnetic interaction. As you use the electricity i.e connect lights etc to it it puts a mechanical load on the engine and slows it down. It you do not use that electricity .i.e don't connect the generator output to anything then it puts no mechanical load load on the engine. It is like your electric outlets at home if you don't plug stuff in then you don't pay for any electricity used, but the generators are still running they just don't need as much fuel as they aren't generating as much energy unless you and everyone else has stuff plugged in using power.

So spinning magnets in front of stator coils creates the potential to generate electrical power as you load up those coils with electrical circuits e.g. lamps then power is generated and used the more power used the greater the mechanical load put on the engine.

Think of a charged battery if you don't connect anything it does not deliver any power or get discharged but as you connect more lamps it gives more power that power was always there but only used when you connect stuff to it. The chemical activity that generates the power only happens when you connect stuff to the battery, the same is true of a generator. As power is used it requires mechanical effort so a generator only generates the power that you demand of it.

An important point is that a generator has a maximum amount of power it can generate so it you ask for to much power the output voltage will sag and reduced the current. A shunt regulator works by putting a big load to ground to force the output voltage to remain at 14.5 volts.

So the way a shunt regulator works is to overload the stator so it can only produce 14.5 volts which happens when it is generating 40 amps. So if the bike needs 15 amps then 25 amps are shunted to ground or just wasted. If the bike needs 20 amps then only 20 amps are wasted to ground. The regulator basically absorbs any excess current to ground keeping the generator giving 40 amps and 14.5 volts. Which is why we keep blowing stators as they always run at maximum power of 40 amps which also generates a lot of heat.

A series regulator works by reducing the voltage from the stator (it effectively puts variable series resistance between the stator and the bike) so that that the output voltage is reduced to 14.25 volts no matter what the current drawn by the bike is.

The series regulator reduces the generator output voltage to 14.25 volts at what ever current the bike is demanding so if the bike only needs 15 amps then the stator only generates 15 amps remember the stator generates 60 volts unloaded at 5000 rpm the shunt regulator overloads the stator to reduce the voltage the series regulator limits the output voltage by limiting the current supplied and reducing the voltage not overloading the generator.

Conclusion a shunt regulator always takes 40 amps from the stator running it at max power and so it eventually burns out whereas a series regulator only allows the current required by the bike to be drawn from the stator which is 15 amps with no accessorize so the stator only generates 15 amps of electricity and the associated heat and so it lasts a lot longer as it is working half as hard as with a shunt regulator where it generate 40 amps worth of heat.

I hope this makes sense.

Dave B that was a great break down of how the tw systems work. Thank you, :beer:

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I just installed a Compu-fire 55402 series regulator; I bought it from Chrome-Addiction.com for $173.

The unit is a little smaller than the standard Honda R&R but the mounting holes line up nicely so installation was easy. I just cut off the stator connector and lengthen the wires then connected them to the new regulator using a connector block. The unit came with 2 long and very beefy power output wires which I connected directly to the battery via the 40 amp fuse that it came with. This avoids using the old cables and connectors that everyone here on this site seems to replace with a VFRness.

The regulator gave 14.25 volts at the battery and was supplying 15 amps to run the bike and charge the battery i.e. much less that the 40 amps that is continuously supplied by original shunt unit most of which is dumped to ground.

The major benefit of the series regulator is that the power supplied is typically half that of the standard unit as it doesn’t regulate by dumping excess power to ground. So I don’t expect to burn up regulators and stators on regular basis as many people here seem to. The regulator is rated at 40 amps which gives it has plenty of reserve power for more accessories.

How is it for keeping cool itself?

I mean when my OEM R&R failed on my 2001, you could fry and egg on the fins (I burned my hand through a leather palmed work glove).

So when I installed the Rick's unit I mounted it on a heat sink plate and now it gets warm, but not hot.

What I'm most concerned with right now is the fact that the Honda wiring harness is causing a nearly .7V drop between voltage at the regulator connector and the battery terminals. Getting a VFRness should solve that issue. It is interesting that the compu-fire unit only needs one positive and one negative output wire.

Still I'm going to be watching this thread to see how the compu-fire unit holds up.

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I just installed a Compu-fire 55402 series regulator; I bought it from Chrome-Addiction.com for $173.

The unit is a little smaller than the standard Honda R&R but the mounting holes line up nicely so installation was easy. I just cut off the stator connector and lengthen the wires then connected them to the new regulator using a connector block. The unit came with 2 long and very beefy power output wires which I connected directly to the battery via the 40 amp fuse that it came with. This avoids using the old cables and connectors that everyone here on this site seems to replace with a VFRness.

The regulator gave 14.25 volts at the battery and was supplying 15 amps to run the bike and charge the battery i.e. much less that the 40 amps that is continuously supplied by original shunt unit most of which is dumped to ground.

The major benefit of the series regulator is that the power supplied is typically half that of the standard unit as it doesn’t regulate by dumping excess power to ground. So I don’t expect to burn up regulators and stators on regular basis as many people here seem to. The regulator is rated at 40 amps which gives it has plenty of reserve power for more accessories.

Could you post some pics of the install? This is on my to do list for my '98 electrical cleanup.

-- Let us how know this works out - you may be the first CF R/R on a VFR.

Here are a few pics sorry i didn't photograph

the unit off the bike

post-20702-0-15308300-1303574516_thumb.j

post-20702-0-99391200-1303574803_thumb.j

The old Honda unit

post-20702-0-61086200-1303574566_thumb.j

Lengthen stator wires

post-20702-0-49614700-1303574640_thumb.j

Battery connection with fuse

post-20702-0-27750000-1303574866_thumb.j

So.......I bought a Compufire and when I went to install it, I realized that if you mount it like the above pic's the fins are running the wrong way for cooling air flow, yes.....no?

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