charging system

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wilcoy02

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I took my gl1100 to a mechanic to see if it was charging ok.

His report showed --- charge @ 2500rpm's was 15.08 volts. Nothing to worry about.

I have both a types of batteries and both seem to be working fine.
Am I looking for a problem that does not exist?

Thanks for any input.
 
Are you looking for a reason why your battery is not holding a charge?If so you are either now going to have to look for the source of the power drain. unless anyone else has a better theory the charging system seems fine. it's how it's used and the rate you need to solve.
Also just to be clear you did say Batteries. how many do you have on the bike and where

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I have an Odessey battery and a lead acid battery. I have been switching them back and forth between bikes. Both always starts the bike.
I thought 15 + volts would eventually fry the battery.
 
15.08 VDC is at the voltmeter or the battery? The system voltage is often higher than what the battery is actually at. Plus, when there is a load on the system, (say 4500 RPMs in 5th gear on the highway) you should see your voltage drop to 14.2 average.

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If your voltmeter is always reading above 15 VDC, it usually indicates bad connections or dying battery.
 
The issue with the 15 VDC is where the RR gets the sense wire signal from. Check the voltage reading on the sense wire. If there is a voltage drop from the battery of say 1 VDC, the RR gets this voltage signal and compares it to the RR reference voltage of approximately 14.2 VDC and adjusts the output to 15.2 VDC, just math - 14.2 + 1 = 15.2 VDC. The unfortunate issue is that the voltage drop on the sense wire, if there is and probably will be, will probably be constant so the RR will continuously put out a greater than RR reference voltage. Your output voltage would indicate that there is a possible 0.8 VDC voltage drop on the sense wire.

You could consider a relocation of where the sense wire is connected into the electrical system to get a more accurate voltage reading without going to the battery. This schematic:
RR Sense Wire with Relay.jpeg
has been modified to show how this can be done. Change at the starter solenoid is not required. In this schematic the sense wire is monitoring the RR output for any fluctuation in electrical system voltage. As the electrical system voltage decreases, indicating an increase in electrical system amperage, the RR will compensate to return the electrical system voltage to approximately 14.2 VDC. Conversely, if the electrical system voltage goes up, indicating a decrease in electrical system amperage, the RR will compensate to return the electrical system voltage to approximately 14.2 VDC.

This modification eliminates the issue of voltage drop across old and tired wiring, and it is easier on the RR and charging system.

As for the battery, after the engine is started, the battery accepts enough power to bring it back to a 100% state of charge and this is at a rate that is ever decreasing, after which it reduces the intake according to the internal resistance of the battery. The battery will take in only what it needs and at this point it results in the battery accepting a trickle charge of say 2-3 amps. Batteries are abused and fail prematurely when the battery is used as a load distribution centre, specifically if loads are attached to the positive battery terminal because you cannot direct where the amperage is going when there is more than 2-3 amps at the battery positive terminal.

The other issue is that the battery is a small load on the electrical system until the electrical system voltage drops to and/or below 12.6 VDC - battery voltage. This generally occurs at low engine RPM. As long as the electrical system voltage is greater than 12.6 VDC, the battery is a consumer not a provider.

Just my thoughts on your issue. Good luck.
 
rednax60.
I love the simplicity and the way you tackled the issues of old wiring in these old ladies. I'm saving this for my winter work.
I hope this simple fix helps others and if there is such a thing as faqs on this forum then this gets a justified move to this area.
mods are you there!

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The schematic was posted by another member, can't remember if it was this forum or another. Can't take credit for it, but understand why it was done. Have the external alternator mod on my 1200 and the sense wire is located where there alternator connects into the electrical system, works well.

The other issue that can occur with a high charging rate is not with the battery but with the electrical/electronic parts. These are designed to operate at a voltage of 14.2 VDC, not 12 VDC. This has been mentioned many times especially with lighting. Headlights dim when alternator output reduces and get brighter when alternator output returns to 14 VDC. Having a sustained alternator output in excess of approximately 14.2 VDC (RR reference voltage) can cause damage to various electrical/electronic parts. Not saying this will happen, but everything has a breaking point. Having mentioned this the issue is to have the alternator output be as close to reference voltage as possible at all times. Cheers
 
i can see on my bike ....i might have to much power hooked directly to the positive post ...but on this 77 bike harness wiring it has the reserve lighting unit crap...mine never worked right since the first day i got the bike ...also by passing it still is no fix ..there was something wrong to begin with ...so it eats batteries in a slow short or something going on ...ill have to just redo that wiring period not just bypass it ..theres no clue in wiring harness to to really figure it out my 2 yr old agm battery id toast now ....
 
I still say that the best and easiest way of testing an alternator is an A/C amprobe or clamp meter.

You just clamp it around each yellow wire in turn (motor running) and if the results (measured in amps) are within + or - 5% of each other. That alternator is good.

Just like testing an electric motor or generator, which at that point, is exactly what it is.

And I still don't understand why anyone would have a problem with that?
 
I read through this but whenever I read threads on electrical theory my eyes gloss over and start to wonder why my brain does not compute this.
 
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