Low voltage

Information and questions on GL1500 Goldwings (1988-2000)
Post Reply
Posts: 1
Joined: Tue Sep 18, 2018 12:57 pm
Location: Montreal quebec canada
Motorcycle: 1992 gl1500 se

Low voltage

Post by Eric9223 »

Hi I have a 1992 gl1500 that seemed to be miss firing and died and I noticed my voltage was at 7.6 I charged the battery and started it up and disconnected the negative terminal on the battery and the bike shut off , does that mean the alternator is finished?

User avatar
Posts: 2408
Joined: Thu Oct 30, 2008 2:46 pm
Location: Lake Oologah Indian Territory USA
Motorcycle: '02 GL1800
2009 Piaggio MP3 250cc

Re: Low voltage

Post by AZgl1800 »

you should never attempt to run the bike with the battery disconnected.

huge potential to burn up a lot of electrics that way.

but, it would seem that the alternator in your case is not working, but not necessarily, if it has a Feedback wire for the Field Windings, you just removed the power to the alternator field, and it will quit working.

The best test, is a voltmeter connected to the battery and watch it while you ride the bike.
or, just rev to 3,000 RPM and if the voltage does not go up to 14.x volts, you have a charging problem.

'02 GL1800
2009 Piaggio MP3 250cc

Posts: 23
Joined: Fri Sep 14, 2018 7:43 pm
Location: Timbuktu
Motorcycle: 1988 GL1500

Re: Low voltage

Post by MarkZ28 »

If the alternator was working, and it was unplugged, you run the risk of burning up the voltage regulator. Its going full field trying to keep the 14 volts. Its supplying as much power to the alternator as it can to keep the set voltage up. You should be ok though since it obviously wasnt charging anyway.

User avatar
Posts: 561
Joined: Tue Jul 11, 2017 11:43 pm
Location: Morgan Hill, CA.
Motorcycle: 1991 GL1500 Interstate (Cinnamon Beige)

Re: Low voltage

Post by bluthundr31 »

Eric9223 wrote:
Tue Sep 18, 2018 1:46 pm
Hi I have a 1992 gl1500 that seemed to be miss firing and died and I noticed my voltage was at 7.6 I charged the battery , , , ,
You seem to have a VM to know it was 7.6v so you should be able to diagnose this issue easily.

Because the voltage is EXTREMELY low, , you might consider replacing that battery unless it went to 12.5-13.0 volts after being fully charged. These batteries seem to prefer a slower charge at 2-2.5 amps for about 10 hours to get a full charge. Larger chargers have been said to "burn" the battery out.

With a fully charged battery, start the bike, hook up your VM to positive and negative posts, stay in neutral, rev engine to 2.5-3k, and watch your voltmeter read 14.1-14.4volts. If you aren't getting atleast 14v, ,there's a good chance your alternator is "going south".

Post Reply