Battery goes dead.
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kartking22
- Rookie
- Posts: 6
- Joined: Tue Oct 17, 2006 1:07 pm
Battery goes dead.
:frusty: I have a 1977 XL 1000 sporster. When I turn on the headlights when I ride, it drains the battery. I checked the generator and it is putting out 13.5 volts. Replaced the voltage regulator after testing it also to make sure that this wasn't the problem. Bike still isn't charging the battery when running the headlights. Battery keeps a charge if I don't turn on the lights. Goes dead after about 50 miles of riding. Well...not completely dead but not enought to start the bike again with the electric starter. I have been through my repair manual several times to try to figure this problem. Any suggestions PLEASE. I have a friend with a 74 sporty with the same problem. Dealership won't even look at it because they can't understand the problem either.
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DieMonkeys
- Legendary 500
- Posts: 702
- Joined: Tue Apr 11, 2006 11:34 am
- Real Name: Mick
- Sex: Male
- Years Riding: 10
- My Motorcycle: 2015/Kawasaki/Versys 650 LT
- Location: Decorah, IA
If you have a volt-ohm meter check for voltage draw and grounds and shorts. Put the meter on the VDC scale remove either the pos or neg wire from the battery, then connect one lead to the wire and the other lead to the battery post where the wire was removed, you should have 2 volts or less, next remove both wires from the battery, set ur meter on ohms scale R1, you should have a high ohm reading between both wires, and probe the pos wire and the other probe to a frame ground, you should have infinity or high ohm readings. If you do have a short curcuit check the wiring that goes thru the handlebars, while leaving the meter hooked up, dissconnect one wire at a time untill the ground goes away. You can also do this with a test light, remove one battery post and hook up a test light in a series curcuit, if the light lights up, you have a short curcuit. Dissconnect wires untill the light goes out, then trace that wire see if its damaged. The older HD's had a problem with the wiring thats routed inside the handlebars.
2011 Toyota Tacoma 4x4, 09 Yamaha Tmax, 08 Suzuki King Quad 750
Clean grounds and wire connections.
Hook an ammeter between the battery and positive cable. Find out how many amps your lighting circuits are drawing. You can calculate what each lighting circuit SHOULD draw in amps by dividing watts by volts. If you have a short, your amperage on that circuit will be very high, though that really should cause a fuse to blow or melt wires.
You can also wire an ammeter between the alternator and battery and see exactly how much amperage the alternator is putting out. It is possible for an alternator to put out good volts, but bad amps. If this is the case, the alternator will show a low charge when the lights are off, and the charge will not change when the lights are on. The alternator should show more charge when the lights are on than when they are off, because more current is flowing through it. If the alternator is on the hot lead on battery "+", it will give an indication of current flow into and out of the battery.
Back in the olden days I snipped plugs from wrecked bikes and had a whole set of adapters to plug an ammeter into a wiring harness in various loacations. It made diagnosis of electrical problems very easy.
Are you running a high wattage headlight bulb?
Hook an ammeter between the battery and positive cable. Find out how many amps your lighting circuits are drawing. You can calculate what each lighting circuit SHOULD draw in amps by dividing watts by volts. If you have a short, your amperage on that circuit will be very high, though that really should cause a fuse to blow or melt wires.
You can also wire an ammeter between the alternator and battery and see exactly how much amperage the alternator is putting out. It is possible for an alternator to put out good volts, but bad amps. If this is the case, the alternator will show a low charge when the lights are off, and the charge will not change when the lights are on. The alternator should show more charge when the lights are on than when they are off, because more current is flowing through it. If the alternator is on the hot lead on battery "+", it will give an indication of current flow into and out of the battery.
Back in the olden days I snipped plugs from wrecked bikes and had a whole set of adapters to plug an ammeter into a wiring harness in various loacations. It made diagnosis of electrical problems very easy.
Are you running a high wattage headlight bulb?
If at first you don't succeed, skydiving isn't for you.
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kartking22
- Rookie
- Posts: 6
- Joined: Tue Oct 17, 2006 1:07 pm
Thanks guys. Sorry for the late response. I'm going to try a few of the suggestions as soon as I find time. Riding season came to a halt soon here in WI. Been cold the last few weeks and didn't have time to tinker with the bike. Below freezing the last three nights. I'll keep you posted if I figure out the problem. Thanks again for the advice.