Shortage of Volts...

My 850 is suffering from a lack of volts.
It has an Alton fitted which gives 12V AC at 1000 rpm, 22V AC at 2000 rpm direct off the alternator wires, unhooked from reg/rect.
When all is connected up again the charging light (RGM, 12.5V when the light goes off) struggles to go off, may go out at 2500 rpm but then comes back on above 3500 rpm!! Multimeter (analogue model) confirms that the charge light is telling the truth.
If i ride it above 3500 rpm for any length of time then i get a misfire and eventually it will cut out (Pazon Altair). Wait a minute or few, or let it run at lower revs and it will go again.
It has a stock wiring loom, one of Al Osbornes modern version of the blue cap, was running a VReg solid state reg/rect but now has a Shindengen with no change of symptoms.
Lights on and things are worse - charge light permanently on.
We have been through the wiring and can't find anything odd, but as I type the only thing which comes to mind that we haven't tried is that the battery may have partially given up? It is a not very old MotoBatt, size to match the Alton.
Any thoughts appreciated.

ntst8 said:

My 850 is suffering from a lack of volts.
It has an Alton fitted which gives 12V AC at 1000 rpm, 22V AC at 2000 rpm direct off the alternator wires, unhooked from reg/rect.
When all is connected up again the charging light (RGM, 12.5V when the light goes off) struggles to go off, may go out at 2500 rpm but then comes back on above 3500 rpm!! Multimeter (analogue model) confirms that the charge light is telling the truth.
If i ride it above 3500 rpm for any length of time then i get a misfire and eventually it will cut out (Pazon Altair). Wait a minute or few, or let it run at lower revs and it will go again.
It has a stock wiring loom, one of Al Osbornes modern version of the blue cap, was running a VReg solid state reg/rect but now has a Shindengen with no change of symptoms.
Lights on and things are worse - charge light permanently on.
We have been through the wiring and can't find anything odd, but as I type the only thing which comes to mind that we haven't tried is that the battery may have partially given up? It is a not very old MotoBatt, size to match the Alton.
Any thoughts appreciated.

Click to expand...

Do a resistance test, (engine off) between the stator wires (disconnected) and then each one to ground (engine case), report back.

concours said:

ntst8 said:

It has an Alton fitted which gives 12V AC at 1000 rpm, 22V AC at 2000 rpm direct off the alternator wires, unhooked from reg/rect.

Click to expand...

Do a resistance test, (engine off) between the stator wires (disconnected) and then each one to ground (engine case), report back.

Click to expand...

+1
Even with a wire almost burned in two, the alternator can give you a good voltage reading as long as there's no load against it. You may need to cobble together a load tester as shown in the manual for verification.

concours said:

Do a resistance test, (engine off) between the stator wires (disconnected) and then each one to ground (engine case), report back.

Click to expand...

Thanks, tested and
- Zero resistance between the two stator wires and
- no connectivity between either stator wire and earth.

ntst8 said:

concours said:

Do a resistance test, (engine off) between the stator wires (disconnected) and then each one to ground (engine case), report back.

Click to expand...

Thanks, tested and
- Zero resistance between the two stator wires and
- no connectivity between either stator wire and earth.

Click to expand...

Let's find out more about the battery, volts at rest? test it? http://www.amazon.com/BA5-100-1200-Cran ... ery+tester

You mentioned RGM charge light, what does the DC voltmeter show when idling? revved in neutral to 2000? 3000 rpm?

Will do, it may be a few days - i am about to head away for a long weekend on my ES2
Just a note that the despite the other issue the battery/Alton has no trouble turning over/starting the bike.

ntst8 said:

Will do, it may be a few days - i am about to head away for a long weekend on my ES2
Just a note that the despite the other issue the battery/Alton has no trouble turning over/starting the bike.

Click to expand...

That's relevant.

Voltage test, the battery had dropped to 12.2V with the motor off (quite a few starts and brief runs while we play around), the motor still fired up easily on the Alton.
Readings off an analogue meter from the battery terminals - headlight off, 1000rpm 12.2V, 2000 rpm 12.3V, 3000 rpm 12.5V (RGM charge light starting to fade on the last one)
Headlight on and the readings are a smidge lower.
iain.

ntst8 said:

Voltage test, the battery had dropped to 12.2V with the motor off (quite a few starts and brief runs while we play around), the motor still fired up easily on the Alton.
Readings off an analogue meter from the battery terminals - headlight off, 1000rpm 12.2V, 2000 rpm 12.3V, 3000 rpm 12.5V (RGM charge light starting to fade on the last one)
Headlight on and the readings are a smidge lower.
iain.

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Your voltage readings are too low. A battery needs minimum of 13.7V to overcome internal resistance and charge properly ,,,, 13.9V is preferable.

A probable cause for your low voltage is the stator coils may be internally shorted. This occurs from vibration breaking the epoxy bond and then the wires in the coil rub together until the wire insulation (varnish coating) wears thru. If two adjacent turns of wire in the coil short, then there is effectively only one turn, and the voltage suffers. Eventually, too many shorted turns of wire in the coils results in the low voltage such as you are seeing. The voltage produced by the coil is a function of the number of wire turns in the coils, magnetic strength and rpm.
It would take a sensitive Ohm meter, and testing each coil individually (scrapping away the insulating varnish each side of each coil) to detect if internal shorting has occurred.

Another cause for these low readings is the voltage regulator is malfunctioning, but I would relegate that to a very low percentage of probability.

Finally, the magnetic strength of the rotor might have become dissipated, but I would rate this as even less probable than the regulator being at fault.

Swapping out the stator or regulator would be the next step.

Slick

As stated in earlier replies, you have an output problem from the alternator / regulator. First, lose the old volt meter and get yourself a digital VOM, Fluke would be nice , but honestly, any decent one will work fine. And YES there is a possibility of the magnetic field of the permanent magnet being low - very hard to determine - trial replacement is an option. It happens in vintage Corvettes with TI ignition, it will drive you crazy......

Thanks for the feedback.
The alternator is the Alton one with under 1000 miles on it, the reg is a new shindengen one but the voltage results are unchanged from the previous shunt type reg so the reg does not appear to be the problem.
Alton seem to be saying from the AC output that the problem is not with their hardware but we are struggling to know what else it could be.
I have had a pm suggesting checking the alternator wires, a loose primary chain has been known to cut a wire, so will have a closer look there.
Other than that still looking for inspiration.
iain.
ps the gap in proceedings allowed 1100 miles on the ES2 over a 4 day weekend :mrgreen:

Try a resistance test on the wire loom: disconnect battery, regulator, and with ignition and all lights off, apply Ohm meter at battery leads. Swap meter leads to get a reading with polarity both ways. Report back.

Slick

ps ... your AC test on the alternator rules out a cut or broken wire at the primary. Did you make any readings at 3000 rpm or higher? Your reading of 22 Vac at 2000 rpm seems OK, but I would expect AC to get as high as 200 VAC at higher rpm's .... say 4000.

I stumbled across this site while surfing, it has a good tech section for the electrically illiterate such as me. http://cycleelectricinc.com It also suggests looking for rogue resistance.
Am now on summer holiday so will have time to get around to a friends shed where the bike is and do the checks.

As a side note it is Interesting that they manufacture series regulators for HD's, for the reasons Jeandr outlined in his Voltage Regulators thread.

Just a technical note, the RGM warning light control unit is a battery voltage monitor and NOT a direct indicator of the charging system, it simply comes on when voltage drops below a specified value. This could be an indication of charging issues but it could also indicate a large voltage draw somewhere, a poor battery or even a high resistance in the wiring to the unit, although your other symptoms do seem to indicate some issues with the charging system.

Are you by any chance using the standard kill switch set up? With this arrangement the power for the ignition has to go through the kill switch points and these get coroded over time and can drop the voltage quite drastically, this can get worse as it heats up. When I use this kill switch I run the ignition wire through an ON-OFF relay and simply use the kill switch to activate the relay to OFF, in normal running the default position is ON and thus this circuit is fail safe.

Thanks Dave,
I am running a kill switch have but have fitted a hydraulic clutch and brembo brake master cylinder, both with modern switch clusters - CNW kits before they had the transition plate to take the original switch gear.
The resistance checks are first on the list at the moment.
iain.

Your problem is probably a loss of magnetism on the alternator rotor due to it having having come into contact with the stator.
If you remove the stator and check the magnetism of the rotor with something like a screwdriver, you will probably find that some of the magnets have lost their magnetism.

Well time does fly, we finally had another play at the weekend.
AC out put confirmed at 35V at 3000 rpm.
Swapped the battery from my ES2 (9AH), sitting at 12.8V a couple of weeks after a 4 day run. The Commando one had dropped to 12.2V from all the playing around, which still spun the Alton with no trouble, but the aim was to see whether there was something odd with the battery.
The Alton spun up easily with the ES2 battery, bike ran nicley and with no lights on the voltage seemed to be doing all the right things - bingo, almost.
Switched the main beam on (Halogen) and the voltage wouldn't go above 12.7V at any revs.
We decided to switch back to the A-Reg 1 reg/rect for size/space reasons and now everything is spot on - but changing out the A-Reg 1 previously have made no difference to things, no better but no worse.
A bit puzzled but looks like a dodgy battery and perhaps an average connection somewhere that has now been replaced?
TIme for a test ride this weekend and hopefully the all clear.

Hi Iain. If your battery is good enough to make the starter work properly, and start the bike, wouldn't it suggest the battery is ok? Good charging systems usually go up to 14.4v, or they did when I was working in the trade in the 90"s.

Dereck


At least you rode a Norton to the rally.

kerinorton said:

At least you rode a Norton to the rally.

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And rode it home

Feed the alternator output directly to the rectifier, omit the capacitor, and if a MK3 the warning light assimilator and ensure that if you are running a modern rectifier the Zener has not been left in circuit.

Then measure the volts at the battery again as you have done previously.