Volt Meter


Information and questions on GL1500 Goldwings (1988-2000)
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TAZZ
Posts: 183
Joined: Tue Aug 25, 2009 11:46 am
Location: Del Rey CA
Motorcycle: 1997 Honda GL1500se
1968 Honda CL350 Scramble,
1970Honda 750k,1976 Suzuki GT550,
1979 Kawasaki 1000st, 1983 Suzuki GS1150se
1986 Kawasaki Ninja 1000R
1981 Honda CBX (STILL have it NOT for SALE)
1982 Honda GL1100 Aspencade 1994 Yamaha700

Volt Meter

Post by TAZZ »



Hi guys maybe you guys can help me here. I have TWO volt meter on my bike one One is on the Battery the other is on Acc. Why two I want to see the different. Ok here is the question went I'm riding and ALL the lights are off only headlight is on Battery meter says 13.9v and Acc. meter 13.4v ok the good but went ALL lights are on and that's ring of fire GPS and LED spot lights Battery meter say 13.9v good but the Acc. meter go down to 12.6v is this a big drop or normal. Stop on a red stop light with everything off RPM at 1500 to 1800 battery meter is at 12.7 Acc meter 12.4v I have AGM battery and Alternator is a 40amps. Is ALL this normal or are I going into some problem down the line. sry about my english


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Swagonmaster
Posts: 348
Joined: Sun Apr 16, 2017 3:30 pm
Location: Stokesdale, NC
Motorcycle: 1990 gl1500 SE

Re: Volt Meter

Post by Swagonmaster »

It is normal to see some difference in voltage if taken directly at the battery and then elsewhere in the harness where there is an electrical consumer. There is some resistance in all wiring and that shows up when current is flowing through the wire which is one reason that it is highly recommended not to add too many things to one wire circuit since there is only so much juice that can go through that wire. Excessive demand is what can cause overheated connectors as, you guessed it, there is some resistance in every connection to add to whatever device is being powered through that wire. Since the available voltage is down to 12.6v the wiring is too small to support the number of lights in that circuit and you will need to put in a dedicated
fused wire from the battery to power the extra lights. Some in the forum have installed a second fuse panel at the battery or behind the left side storage pocket for that purpose.
The original alternator being only a 40 amp output and no alternator can produce max voltage at idle it's at a serious disadvantage at low speeds. Since you are seeing 12.7 volt at the battery at fast idle speed and that is without the extra load there isn't really enough current being produced to keep the battery up if you drive a lot of stop and go at low speed (12.7 is minimum for a "fully charged battery") it would be expected to show over 13v at that point so it's very marginal. It would be good for you to consider upgrading to a 95 amp alternator to prevent problems.
Btw, make sure to have reasonable size wire to the voltmeters so they don't lie to you, they don't take much to power up but wire and connection resistance is a bitch.
Try to learn from the mistakes of others..... you won't live long enough to make them all yourself!
User avatar
TAZZ
Posts: 183
Joined: Tue Aug 25, 2009 11:46 am
Location: Del Rey CA
Motorcycle: 1997 Honda GL1500se
1968 Honda CL350 Scramble,
1970Honda 750k,1976 Suzuki GT550,
1979 Kawasaki 1000st, 1983 Suzuki GS1150se
1986 Kawasaki Ninja 1000R
1981 Honda CBX (STILL have it NOT for SALE)
1982 Honda GL1100 Aspencade 1994 Yamaha700

Re: Volt Meter

Post by TAZZ »

Thanks Swagonmaster Yes I have a second fuse panel at the battery to run some wire with fuse, this is the funny part I have 2(two) 40amps alternator long long time ago my bike stop i didn't know want was going on tow bike home took bike to shop and they say it was the Alternator so new 40amps hitachi was install the old one I send it to Ken Heming (MARS) to rebuilt. I just install the rebuilt one and the went is saw the amps is about .3 to .4 lower than the other that the funny part. I can't talk to Ken about it cause he past away I being thing about getting 90amps but hear bad think about it for some of the other guys with problem return it. I took the alternator out to clean it blow out dust so I install rebuilt one that went I saw Amp .3 to .04 lower. Also I like to ask the wire the come down black/green and Green the go to alternator can it be cut and Add some wire to make it little longer. Thanks
User avatar
Swagonmaster
Posts: 348
Joined: Sun Apr 16, 2017 3:30 pm
Location: Stokesdale, NC
Motorcycle: 1990 gl1500 SE

Re: Volt Meter

Post by Swagonmaster »

Yes, you can lengthen the wire but make sure to get a good connection or you will hurt the alternator's ability to charge, remember every connection has some resistance.


Try to learn from the mistakes of others..... you won't live long enough to make them all yourself!
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