BaZa
Member
Troubleshooting your charging system
CARRY A GREAT TOOL
Buy a £10-£15 voltmeter from any car parts place and take it with you everywhere. If it won't help you because you never break down, it will help the next guy. Change the meter battery every year.
ROUTINE CHECKS FROM THE SAFETY OF YOUR GARAGE
At winter's end and even now and again during the season, get that meter out.
With battery in place on bike, put the red lead to battery positive terminal and the black lead to earth terminal, after setting the meter to the DC voltage figure just higher than those which you are looking for (usually ''20'')
You should get a reading of 12.6-12.9 DC volts. Any less and you will encounter starting problems - most of the capacity of a Harley's big battery is for the starter motor. (Kick start only? You're still good to go until it drops below around 11 volts!)
I did read once that if 12.9 volts is a 100% charged battery, 12.5 is about 50% charged. Sobering....don't think that 12.2 is good. It's knackered.
If battery needs charging, use an OptiMate or similar - these deliver a SLOW trickle charge and can recover even a deeply discharged battery.
(Fast charging using car-type chargers will shorten the life of your battery. You should disconnect your battery if not riding over winter, and preferably leave it on an OptiMate or similar. Batteries do discharge slowly over time, especially when hooked up.)
Check on....with the bike running, confirm that the correct charge is getting to the battery - place meter leads as before and at fast idle the voltage should read around 13.5 volts DC.
Rev the bike - the voltage should go no higher than around 14.8. Fifteen volts and above is a no-no - this means the regulator is not regulating and the extra voltage will surely boil the battery dry while you're out on the road. Even refilling can be pointless due to plate damage caused by boiling....
Your regulator needs an excellent connection to ground to regulate, i.e. shunt the excess alternator current to earth.
Some regulators are earthed by body by being securely connected to the frame, some through a wire to frame (which acts as ground in either case). Check this connection if you are reading too much (15 or over) DC voltage at the battery.
Use star-type washers that 'dig in' with either method - AFTER removing any paint or powdercoat. Bare metal gives the right connection.
If the voltage does not rise, that's not good either. Check it a second way by turning on the lights - they should brighten slightly as you rev the bike because the charging voltage is rising to the ideal 14.5-14.8.
If not, the connection from regulator to battery may have failed (see below).
And there's more.....If you are getting normal charging voltage but when you rev harder said voltage plummets, even to zero, in all likelihood the regulator is breaking down at the higher rpms. Replace.
Also, if the regulator is trying to charge into a defective battery (and cells or plates can fail without warning due to age or too much current coming in) it will immediately go to max output, then if it continues at this level, the output circuit will fail, which renders the regulator useless.
Tricky blighter, Johnny Regulator......
CARRY A GREAT TOOL
Buy a £10-£15 voltmeter from any car parts place and take it with you everywhere. If it won't help you because you never break down, it will help the next guy. Change the meter battery every year.
ROUTINE CHECKS FROM THE SAFETY OF YOUR GARAGE
At winter's end and even now and again during the season, get that meter out.
With battery in place on bike, put the red lead to battery positive terminal and the black lead to earth terminal, after setting the meter to the DC voltage figure just higher than those which you are looking for (usually ''20'')
You should get a reading of 12.6-12.9 DC volts. Any less and you will encounter starting problems - most of the capacity of a Harley's big battery is for the starter motor. (Kick start only? You're still good to go until it drops below around 11 volts!)
I did read once that if 12.9 volts is a 100% charged battery, 12.5 is about 50% charged. Sobering....don't think that 12.2 is good. It's knackered.
If battery needs charging, use an OptiMate or similar - these deliver a SLOW trickle charge and can recover even a deeply discharged battery.
(Fast charging using car-type chargers will shorten the life of your battery. You should disconnect your battery if not riding over winter, and preferably leave it on an OptiMate or similar. Batteries do discharge slowly over time, especially when hooked up.)
Check on....with the bike running, confirm that the correct charge is getting to the battery - place meter leads as before and at fast idle the voltage should read around 13.5 volts DC.
Rev the bike - the voltage should go no higher than around 14.8. Fifteen volts and above is a no-no - this means the regulator is not regulating and the extra voltage will surely boil the battery dry while you're out on the road. Even refilling can be pointless due to plate damage caused by boiling....
Your regulator needs an excellent connection to ground to regulate, i.e. shunt the excess alternator current to earth.
Some regulators are earthed by body by being securely connected to the frame, some through a wire to frame (which acts as ground in either case). Check this connection if you are reading too much (15 or over) DC voltage at the battery.
Use star-type washers that 'dig in' with either method - AFTER removing any paint or powdercoat. Bare metal gives the right connection.
If the voltage does not rise, that's not good either. Check it a second way by turning on the lights - they should brighten slightly as you rev the bike because the charging voltage is rising to the ideal 14.5-14.8.
If not, the connection from regulator to battery may have failed (see below).
And there's more.....If you are getting normal charging voltage but when you rev harder said voltage plummets, even to zero, in all likelihood the regulator is breaking down at the higher rpms. Replace.
Also, if the regulator is trying to charge into a defective battery (and cells or plates can fail without warning due to age or too much current coming in) it will immediately go to max output, then if it continues at this level, the output circuit will fail, which renders the regulator useless.
Tricky blighter, Johnny Regulator......
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