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1993 GL1500 - Charging Question

2K views 16 replies 12 participants last post by  poconoracing 
#1 ·
Happy Fathers Day!

Bought a LAtrical Alternator at in April to give me enough juice for the heated clothing I wired into the bike.

Worked fine for about 2000 miles, voltmeter (aftermarket) showing a pretty steady ~13.7 volts. Then all of the sudden it dropped to 12.6 and down. Alternator stopped charging. Warranteed the alternator (fine process other than it cost me $20 to send it back) and installed the new one and it works .... but....

It seems like the alternator goes to sleep on long rides. For example, I rode it about 200 miles yesterday, no heated clothing required. on some of the longer legs the volts would drop to the 12.6-8 range. From my multimeter testing the voltmeter gauge is about .2-.3 lower than the voltage at the battery posts. It's wired on the accessory circuit so that makes sense. As soon as I apply the brakes (or any other new electrical load) the voltmeter would jump .5 to 1 volt and then slowly drop back after the load was removed.

Is it telling me the battery is at full charge? or is there something up with the sense circuit? From the posts on here you guys are seeing a consistent voltage over 14 volts. It's a Deka AGM battery installed with the first alternator in April. Cleaned all the terminals. No loose wires or anything I can find.

Seems to start fine, 13+ volts after starting. Any thoughts?
 
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#2 ·
once the battery gets to full charge, the regulator scales back the output to maintain 13.6-14.1 volts.


the one on my 1800 seems to hover around ~14.1 volts most of the time.
but that is what I see on the voltmeter scale.


this pix was taken Key OFF, after me piddling around on the bike a bit.


when I first start it up, it jumps up to 14.8ish
 

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#3 ·
If the voltmeter is .2-.3 lower than the battery posts then that means 12.8 to 13.1 at the battery posts when the voltage drops.

This suggests a full battery, and alternator simply maintaining it. Static fully-charged battery voltage should be 12.7v at the posts - neither load nor charge.

If the voltage at the posts starts sinking below 12.7v (below 12.4-12.5 on your gauge) then you are discharging and need to look for a problem.
 
#6 ·
Thanks for all your posts.

I guess I'm being thrown by all the folks indicating they are seeing a consistent 14V in the other posts on the subject.

Key on it reads 12.5V, Cranking it drops to about 10.5. Once it starts it goes high (13.9 on my voltmeter) for a few minutes, then slowly drops to the lower voltage as I ride, again jumping up whenever I apply the brakes or turn on the radio etc.

I'll run it a while and keep an eye on it. I have a garden tractor with a voltmeter and it does the same thing the goldwing is doing. Voltmeter goes up over 14V or so when you first start it, then a few minutes later its down just below 13.
 
#7 ·
Thanks for all your posts.

I guess I'm being thrown by all the folks indicating they are seeing a consistent 14V in the other posts on the subject.
.



I try to always l comment that my Voltmeter is wired DIRECT to the battery's terminals....


that is why mine shows 14.1 to 14.5ish


14.1 all the time while riding on my bike,
 
#10 ·
My 1500(1996) after first original alternator died at 34k miles, it never charged more than 13.8!! I ended up putting a car battery in saddlebag and wiring it to it to give more of a charge for starting and bigger capacity for lights. It worked but I didn't trust it. I put in a compufire and never hit 14 volts. No issues with new 1800 goldwing. Alternator good after 100k miles and charges at 14.6 volts.
 
#11 · (Edited by Moderator)
Reviving an old post from last year, because I did eventually solve the mystery of the low voltmeter reading. It may help someone with a similar issue.

It turns out the primary + battery cable was corroded internally. The cable has 2 legs, one goes to the starter circuit, the other goes to the bike main power fuse to run the lights/accessories etc. Right about where the blue arrow is, the green crusties were growing inside the insulation. You could not see any evidence at all of it from the outside.

I found it when I was putting the side cover back on over the battery, and in the process pushed on that wire. The voltage dropped on the voltmeter. I narrowed it to that specific section of wiring. My assumption is the resistance caused by those crusties was amplified in the voltmeter reading as the power output of the alternator to the now charged battery diminished. Less Amps means crusties have a larger effect on the Voltmeter.

The fix was to replace the OEM cable.

Intermittent electrical issues suck.
But the LaTrical Alternator is now keeping the system happy at 14V

322244
 
#17 ·
Hopefully it helps the next guy. It's important to close the loop on issues, and thank those who have helped you along the way!

On a side note - the voltmeter will show 14-14.1V on startup and fall to 13.8-9 and stay there after about 5 minutes. Turning on the heated grips and both jackets it will fall to about 13.5.
 
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#14 · (Edited)
Mine has the Comp-U-Fire, I see 14.2 or sometimes higher just after start, but it settles to 13.6-13.7 once warmed up.

My volt meter is wired through accessory activated relay to battery with a 5amp fuse, I thought the plug & play location was showing me less than real charge, but it was less that 1/2 volt off.

In 2005 I had a OEM alternator in it short term, saw essentially same readings.
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#15 ·
My 1500 is all taken apart for upgrades and reassembling the stereo (finally). I have a "Max Tow" volt and oil pressure gauge set going in an "Unobtanium" panel I got from Bluthundr31, These gauges are sweet - have a 270 degree stepper-motor driven analog gauge movement plus a three digit digital display in them. Powered by the accessory terminal but they have a power lead that goes direct to the battery too, this for memory "keep alive" to remember your backlight dimmer settings. The nice thing about this is the voltmeter takes its voltage readings from the lead direct to the battery, not the accessory power.

Just for fun, I measured the parasitic draw on these gauges from the battery, it is right next to absolutely nothing. And on the test bench the digital volt meter agrees 100% with my Fluke DVM.
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It will be interesting to see my voltage readings once the bike is back together.
 
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