Hi again. 1983 R80RT /7 17k Sat 20 years but was running when I bought it.
Took it for a ride after putting in fork seals and front pads. After the ride I parked it in the garage and forgot to hook up to the little charger. A week later it wouldn"t crank. Figured the battery couldn't hold a charge and put in a new one. Took another ride and when i got back to the garage hooked up the charger. I monitored the red light on the charger and found that It took over an hour until the green light showed that it was charged. Typically takes only 5-10 minutes after a ride for the green light to come on. I also noticed the voltage on the dash board only went to 13v. Bought a used electronic (red) regulator and fired it up. Still 13v max and a long time to charge. I read a conversation NO SPARK and they mentioned that the voltage is adjustable with certain regulators. the original one that came on the bike I believe is the mechanical one (its has an aluminum case). The mounting screws couldn't come loose so its still mounted.
1 is either the red one or the original adjustable?
2 if not which is the one that is adjustable and where do you get it?
3 I didn't have an ammeter to check the amperage but the idiot light goes out.
Any other thoughts on the problem. I read that I need over 14 volts for an AGM battery.
Thanking y'all in advance!
Dave
Several thoughts...
• The BMW dashboard ammeter typically reads ~1 volt lower than the actual system voltage.
• You can get an adjustable regulator from Motorrad Elektrik. http://motoelekt.com/charging.htm
• Each brand and type of battery has an discrete suggested charge voltage. Check with the manufacturer before adjusting your new regulator.
• Have you checked BOTH your battery cables for damage along their full length ?
• Have you replaced your alternator brushes ?
• Is the RED alternator output lamp working ? That is, does it come ON before starting and go OFF after cranking ? (You mentioned this but not with any detail.)
• A battery is like a checking account in that it can go "bust" 2 ways: 1) Not getting enough input, or 2) Having too much going out. So your problem doesn't necessarily have to be one of Charging Deficiency. It could just as easily be a large drain when the bike is running, or small drain when the bike is parked. Pull the headlamp bulb and check the wattage. If there are any accessory "road lights" disconnect them. Check that the ignition switch turns everything OFF (heated grips is always a biggy) because over the span of a week, all it would take is a couple of tiny dash lights left ON to bleed the battery down.
Hope this helps.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Thank you very much Wobbly. Last night I ordered an adjustable voltage regulator. If necessary I will buy an ammeter.
The charging light is on before starting and goes off after starting and a slight rev of the engine.
One question I just thought of: does the idiot light go out if there is a diode burned out?
Also, I will check the voltage with a meter when the bike is running.
Thanks again, Dave
Hi Wobbly, figured i would give you an update. The voltage was 13 using a meter. I received the adjustable regulator from EME to 14.35v. The other company only has a 14.2 non-adjustable, Its been raining here so I will check it out soon. Thanks again for the help.
Dave
Hi Wobbly, figured i would give you an update. The voltage was 13 using a meter. I received the adjustable regulator from EME to 14.35v.
Yes, thanks! I love updates.
The important question is WHERE this measurement was taken. It should have been measured directly across the battery terminals, not from any locations on the harness.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
it was at the battery terminals. 14.35v
Dave
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