Voltage regulator and battery drain

[Vickersguy]

I've had a battery drain for some time. If left for a week, the battery need to be charged to turn over the bike. Also, the battery does not seem to be charging. The search method was to disconnect stuff till the voltage between the battery ground wire ( disconnected from the battery ) and the negative terminal on the battery, was zero, with the key in the off position. Before I disconnected any circuit, the voltage between the ground wire and the negative terminal was around 6.8 volts DC. First thing I unplugged was the battery probe on the wet cell battery. That drove the voltage at my digital meter to 12 volts. Put it back in, it went to 6.8 volts again. Popped the fuses in the fuse box ( original ) and there was no change. It stayed at 6.8 volts. Then, I checked the stator and all resistances were good and no shorts to ground on the three stator wires. Then I unplugged the voltage regulator and the voltage dropped to zero. I've had intermittent battery warnings on the LCD monitor and the voltage on the voltmeter in the interment pod has never gone anywhere near 14 volts, at best I've seen 12.5 on that display. I ohm-ed checked the regulator and it seems OK but I didn't fine a good thread on properly ohm-ing the regulator out. I suspect I've got a bad regulator as the stator has the cooling ring and it seems electrically sound. I did not check the body of the regulator housing to the pins on the regulator plug. Perhaps there is a short there. I'd appreciate any thoughts or direction anyone might have. Even though a used regulator is only $16 from pinwall, I'd rather not have another spare part I don't need and digging out the regulator is not a job I really want to do unless necessary. Tomorrow I will fire it up and see what the voltage is across the battery terminals while running at 2000 rpm. It might be fine at 14 volts or close but if it is, it still doesn't address the battery drain.

[Chaharly]

I've had a battery drain for some time. If left for a week, the battery need to be charged to turn over the bike. Also, the battery does not seem to be charging. The search method was to disconnect stuff till the voltage between the battery ground wire ( disconnected from the battery ) and the negative terminal on the battery, was zero, with the key in the off position. Before I disconnected any circuit, the voltage between the ground wire and the negative terminal was around 6.8 volts DC. First thing I unplugged was the battery probe on the wet cell battery. That drove the voltage at my digital meter to 12 volts. Put it back in, it went to 6.8 volts again. Popped the fuses in the fuse box ( original ) and there was no change. It stayed at 6.8 volts. Then, I checked the stator and all resistances were good and no shorts to ground on the three stator wires. Then I unplugged the voltage regulator and the voltage dropped to zero. I've had intermittent battery warnings on the LCD monitor and the voltage on the voltmeter in the interment pod has never gone anywhere near 14 volts, at best I've seen 12.5 on that display. I ohm-ed checked the regulator and it seems OK but I didn't fine a good thread on properly ohm-ing the regulator out. I suspect I've got a bad regulator as the stator has the cooling ring and it seems electrically sound. I did not check the body of the regulator housing to the pins on the regulator plug. Perhaps there is a short there. I'd appreciate any thoughts or direction anyone might have. Even though a used regulator is only $16 from pinwall, I'd rather not have another spare part I don't need and digging out the regulator is not a job I really want to do unless necessary. Tomorrow I will fire it up and see what the voltage is across the battery terminals while running at 2000 rpm. It might be fine at 14 volts or close but if it is, it still doesn't address the battery drain.

 

With the bike running check the voltage drop from the 5 wire (4 wire plug on some bikes) to the battery. There are 2 black and to red wires and probably one brown wire coming out of this plug. Set your multimeter to the 20V DC setting and insert one probe into the plug on one of the red wires. Then put the other probe on the positive lead to the battery. If you've got anything like .5 v showing up then you're losing a half a volt in just that one wire. Repeat this process with the other red wire, and then do the same with the black wire, but to the ground post instead. Same thing, you're looking for a voltage drop. I would say like .1 to .2 volts is acceptable.

 

This will at least eliminate the harness and connections to the battery being the problem. I would definitely do this before buying a regulator.

[Vickersguy]

Finally found Freebird's A/C voltage check for the regulator output. I will check this in the A.M. Voltages never go higher than 13.8 volts regardless of the rpm. It even drops to 13.2 volts at 3500rpm from the high of 13.8 at 2000 rpm.