Poor Boy Question

[marksaunders]

I have my Poor Boy conversion completed and it's working great. I just have a question. At 3000 RPM I'm showing 14.4 volts which is perfect. If I turn my blinker on it drops to 13.8 volts when the lights flash. Is this what everybody else is seeing? I figured the voltage would be constant due to the alternator change.

[BigBro]

I don't notice that much voltage drift.
Where is your voltmeter connected?

[marksaunders]

I have it connected to the acc posts on the fuse box on top of my air filter housing.

---

I'll try testing a connection at my battery and see if there are any differences tonight.

[admin]

You may be able to replace the voltage regulator in your new alternator with a more precise model used in taxis and police cars that will keep the voltage roughly constant but it will cost big bucks. 13.8 volts is not bad considering that you have a headlight and the 3 bulbs (front, rear and dash) for the turn signals operating as well as the turn signal electronics. A much cheaper way to keep the voltage from dropping is to replace incandescent bulbs with super bright LED's. Just drive it the way it is and be happy knowing that your charging system is now reliable.

[BigBro]

That would most likely be why you see a drop.
The wiring coming to that point goes through the entire bike frame, multiple connections and switches.
Since everything takes it's source from that point the voltage you see would tend to fluctuate with varying loads.

I measure my battery voltage at the battery since that is also where the Alternator upgrade applies charging voltage to.
You should also be sensing voltage for the alternator fairly close to that point. I used the switched source coming to the on board regulator to get my battery voltage sense for the Alternator.

I can say I notice a slight drop(.1 to .2 volts) when I turn on the headlight but the alternator definitely picks up the load for it. 55W is around 4 + amps depending on how you calculate that.

It works well.

Hope that helps.

[neoracer]

i would not worry about the slight voltage drop at times as long as it recovers which it will do since an alternator system recharges a battery alot faster than a stator system does

[bs175dths]

I don’t know my pulley size, but I get a constant 13.5V (voltmeter) coming out of my ACC., and 14.2 (DMM) at the battery. When I apply my brakes, my voltage drops momentarily then picks right back up. (running incandescent bulbs) The voltmeter needle deflection is dramatic to watch when the directional is on, but my battery has shown no loss of power over time. I have over 7000 trouble free miles on my conversion and couldn’t be happier. I am planning on changing the meter from the ACC. to the battery (through a relay) when I find the time. In the meantime, the charging system seems to be working as it should.
As was suggested, ride the bike for now keeping a watchful eye on the voltmeter and learn what the system is doing when called upon.
Yours is probably like mine in that it is MUCH better than before, but could use a bit of refinement.

-Ride On

[marksaunders]

I'm just going to ride for the rest of the season and not worry about it.

[joe turner]

I'm just going to ride for the rest of the season and not worry about it.

It will be all right, my voltmeter needle bounces with the turn signals.

[Scot Thompson]

I'm just going to ride for the rest of the season and not worry about it.

It will be all right, my voltmeter needle bounces with the turn signals.

I'd like to make an observation on this subject. A one-wire alternator will monitor the battery sense at the battery but that is not the best place to monitor voltage. It would be just like taking the "sensor" wire and attaching it to the batt terminal on the alternator or to the battery post itself if a three-wire alternator is used. I note that Mark's volt meter is taking voltage from the ACC terminal and that his voltage drops when blinkers are turned on, etc. That is also where the voltage should be sensed by the alternator so that the alternator can increase its output to provide the desired voltage at the place it is being consumed. This will mean the voltage seen charging the battery is higher than if the sensor wire were attached at the battery (or if you used a one-wire alternator). By "sensing" the voltage nearer to where the power is being used, the charging system is compensating for voltage drops from the wires, junctions, headlights, etc. and this is the way the charging system was designed to function. Headlight, tailights, driving lights and turn signals will be brighter.

This is easy to do on these old Wings, the black wire with green stripe at the 8-pin connector for the rectifier/regulator comes from the "bike side" of the ignition switch. Not only did Honda use it for the exciter voltage for the R/R, but it provides the voltage sense to the regulator function of the R/R so it "knows" what dc voltage to output. Using that wire for the external alternator sensor (S terminal) and on/off (I or IG treminal) terminals will regulate the alternator as it was intended. Scot

[bs175dths]

I'm just going to ride for the rest of the season and not worry about it.

It will be all right, my voltmeter needle bounces with the turn signals.

I'd like to make an observation on this subject. A one-wire alternator will monitor the battery sense at the battery but that is not the best place to monitor voltage. It would be just like taking the "sensor" wire and attaching it to the batt terminal on the alternator or to the battery post itself if a three-wire alternator is used. I note that Mark's volt meter is taking voltage from the ACC terminal and that his voltage drops when blinkers are turned on, etc. That is also where the voltage should be sensed by the alternator so that the alternator can increase its output to provide the desired voltage at the place it is being consumed. This will mean the voltage seen charging the battery is higher than if the sensor wire were attached at the battery (or if you used a one-wire alternator). By "sensing" the voltage nearer to where the power is being used, the charging system is compensating for voltage drops from the wires, junctions, headlights, etc. and this is the way the charging system was designed to function. Headlight, tailights, driving lights and turn signals will be brighter.

This is easy to do on these old Wings, the black wire with green stripe at the 8-pin connector for the rectifier/regulator comes from the "bike side" of the ignition switch. Not only did Honda use it for the exciter voltage for the R/R, but it provides the voltage sense to the regulator function of the R/R so it "knows" what dc voltage to output. Using that wire for the external alternator sensor (S terminal) and on/off (I or IG treminal) terminals will regulate the alternator as it was intended. Scot

I just want to clarify the last sentence.
What you are suggesting is to use the Black wire with the Green stripe of the 8-pin connector of the late Rectifier/Regulator at the I (or IG) AND the S terminals of the external alternator.

Interesting.

[Scot Thompson]

I'm just going to ride for the rest of the season and not worry about it.

It will be all right, my voltmeter needle bounces with the turn signals.

I'd like to make an observation on this subject. A one-wire alternator will monitor the battery sense at the battery but that is not the best place to monitor voltage. It would be just like taking the "sensor" wire and attaching it to the batt terminal on the alternator or to the battery post itself if a three-wire alternator is used. I note that Mark's volt meter is taking voltage from the ACC terminal and that his voltage drops when blinkers are turned on, etc. That is also where the voltage should be sensed by the alternator so that the alternator can increase its output to provide the desired voltage at the place it is being consumed. This will mean the voltage seen charging the battery is higher than if the sensor wire were attached at the battery (or if you used a one-wire alternator). By "sensing" the voltage nearer to where the power is being used, the charging system is compensating for voltage drops from the wires, junctions, headlights, etc. and this is the way the charging system was designed to function. Headlight, tailights, driving lights and turn signals will be brighter.

This is easy to do on these old Wings, the black wire with green stripe at the 8-pin connector for the rectifier/regulator comes from the "bike side" of the ignition switch. Not only did Honda use it for the exciter voltage for the R/R, but it provides the voltage sense to the regulator function of the R/R so it "knows" what dc voltage to output. Using that wire for the external alternator sensor (S terminal) and on/off (I or IG treminal) terminals will regulate the alternator as it was intended. Scot

I just want to clarify the last sentence.
What you are suggesting is to use the Black wire with the Green stripe of the 8-pin connector of the late Rectifier/Regulator at the I (or IG) AND the S terminals of the external alternator.

Interesting.

I too, am making the conversion to Poor Boy's setup. And before I answer the question, I need to verify to myself the functions of the terminals on the Geo Alternator. Normally on an alternator, there is a Batt terminal - stand alone post; there is a 2, 3, or 4 spade connector with the following functions: I or IG - this is a switched feed from the ignition used to turn the regulator on; L terminal provides a ground to turn on the idiot light when the alternator goes kaput; S to provide sensor voltage that is normally taken on the far side of the ignition switch.

So here is the problem I am having and why I am cautious in answering: on the Geo alternator, I have been told the following: Batt post is normal; inside the connector as you look at it, the left spade is the IG, the right is the L and the upper spade is the D (but normally, it should be the S). D stands for Dummy and it has no function. I am searching for the Geo's wiring schematic, so I can verify the connections and I will not hook up until I see it just because I am trained that way. However, assuming the IG is correct and the D is simply a blank, we do not need the L (although you want to assure the alternator is properly grounded through the mounts, right?), then connect the Batt to the battery positive via a circuit breaker or fuse, connect the black w/ grn stripe from the bottom half of the old 8-pin connector at the old R/R to the IG spade and you're done. Do assure there is continuity between the alternator's case and the ground lug on the frame of the bike. Again, assuming all is as stated above, the Geo alternator will be using the IG terminal to provide sensor input to the regulator as well the on/off voltage the regulator needs to function.
Anyone have the Geo schematic?
Here is a link to a pretty good primer on alternators: http://www.autoshop101.com/forms/alt_bwoh.pdf

[SIR tricky]

here it is

[Scot Thompson]

here it is

Thanks to you, Tricky. So the dummy is a dummy, interesting. Just exactly like Poor Boy said years ago! (I don't know why I always have to re-invent the wheel...personality flaw I guess!)

I measured the voltage drop for the black with light green stripe wire found on the bottom half of the 8-pin connector at the R/R. A little inaccurate because the battery voltage starts to fall the minute the lights are on, but I found 12.7 vdc at the battery. Turned on the ignition and found 12.21 vdc at the battery; moving around a little. Then the voltage on the Bl w/G strip wire was 11.79 vdc. Or, about 0.5 voltage drop. The ignition switch is provided power from the battery on a red wire and in the on position, it is switched to the fuse box via a black wire. The number 4 fuse is the ignition fuse and that fuse connects the bl w/ gn stripe going to the R/R and a few other devices. So, the voltage drop is from the battery through the ignition switch through the fuse and to the 8-pin connector. I measured the resistance of the bl w/ gn stripe wire between the 8-pin and the fuse and it was neglible...under 0.1 ohm.

I think the 0.5 voltage drop over that loop is quite normal. So, I will use the 8-pin connector as the source for my Geo alternator IG connector. On my setup, there is no discernible resistance between the alternator and the ground lug on the bike's frame, so that is goodness. If I hook the batt connector of the alternator to the battery positive via a circuit breaker or fuse, all should be well.

So, Mark, I think that is the answer to your question. Batt terminal to the battery, IG terminal to the bl w/gn stripe at the 8-pin (no need to fuse the IG wire as it is fused in the fuse box). This will provide sensor voltage on the far side of the ignition switch as well as switched power to the alternator only in the "On" position. Pretty simple.

[bs175dths]

I ran a lead from the ACC of the fuse box to excite the Geo alternator and haven't had any charging issues.
I will change over to the Bl/Gr wire of the R/R plug and see if there are any improvements in the system.

Thanks for the details.

-Ride On