OK I just got my bike out of the shop. I noticed close to home that the battery light was on. I pulled over and tryed to figure out what was the problem. I killed the engine. Then turned it back on and cranked the bike. the battery light went off. I noticed when I cut off my 50watt Harley fog lights and running lights and only had the main head light on that the voltage would go back up to 13.8 but i could turn the lights back on and the voltage would drop to about 11.9 volts.
I thought when you cranked the motorcycle, that it would run everything off its own power without the battery. I believe the battery has a dead cell in it. Would this cause the voltage to fall like that ? Thank You for your help

 

On a Harley, you are running everything off of the battery not the charging system like in a car. On a car, if you disconnect the battery everything will keep on running off of the charging system but on your bike if you disconnect the battery while it is running, it will die and everything will go dead.

 

Sounds like the charging system isn't putting out enough power for everything your running. Possibly your stator or regulator going out. What was it in the shop for and how long? If you are using heated gear, stereo amplifier or other high wattage equipment you may want to get the high power charging system.

Sometimes a battery going bad/low or jump starting can cause the stator or regulator to go bad (and visa-versa).

 

Sounds like the voltage regulator or the output of the charging system in off. How old is the battery?

 

The battery is about 18 months old.

 

I had that same thing happen on my '86 FLHTC. It was the stator on that bike, that time.

 

Time for a service manual & a multi-meter. Check out the charging system. I would be surprised if you have a bad battery after 18mo.

 

Check your battery connectons. ie. remove and clean.Costs nothing!

 

Guy who worked on the bike said He had a hard time charging the battery. It did sit there for three months in really cold weather. the bike cranks well no problem. I had no issue before i took it to his shop. After they worked on the engine i did have a problem. I installed a new battery this evening. Same problem. I turned off the fog lights and the gauge went back up to 13 volts. I checked all the wiring to the lights and they were ok. It never bothered the bike before. I think something went wrong with the stater while they were working on it. Who knows. Maybe a bad connection or something. thats why im asking now. thought it could be something i could repair

 

you are seeing a voltage drop. Amperage is what counts. Have some one check the output of the charging system to see if there is a problem. Unless you know how to use the multimeter and an ammeter also. You said the guy who worked on the bike had a problem charging the battery, was he charging the battery with the engine or a battery charger? I wouldn't rule anything out at this point, and don't blame the mechanic yet. Coincidences do happen...