Battery keeps going dead

[Polluted]

I have a 1982 gs850g. The battery kept going dead on it when I bought it two years ago. After about 2 weeks of daily commuting the battery wouldn't start the bike. I noticed starts getting harder progressively up to no start. Put it on the battery charger and good for another 2-3 weeks. I've been doing this for two years. I replaced the battery with a new one and ran the through the charging system test in the stator papers. My results are: with my headlight unplugged (I live in US) and engine at idle I get 13.1V that slowly creeps up to 13.45V. Revving the engine to 5000RPM drops the Volts to about 13.25. When I plug the headlight in and retest the charge being received I get 12.1V and slowly creeps up to 12.4V. But again it goes down when I rev the engine. I tested the stator output and the r/r diodes. All tests performed well and don't seem to be the problem. One other note, one of the wire connections from the stator was slightly burnt. The other two had a little blackness on them also. I replaced he connections and the results are what I listed above. Any ideas on where to start looking?

[Nessism]

How is your R/R ground? What kind of AC voltage do you get out of the stator?

[1_v8_merc]

You're sure the tests checked out?
Even if all tests check out, you can still have faulty components.

You should easily have 13v with headlights On(bike running at idle)
Sounds like a RR or Stator problem, because it's not working under Load.

[tom203]

Is your stator wired direct to R/R ? and what type of R/R, any numbers ,photos? You can test the rectifier portion ( the main diodes) simply, but checking the regulating portion of the R/R is iffy. Seems that yours is having trouble as stator puts more load into it. I'd rerun the stator tests. You can pick up a used Shindengen R/R cheap- this is a quickie way to rule out a R/R problem.

[Polluted]

I'm sure all the tests checked out. I have a little experience with electrics. The rr ground had 0.09 volts dropped from battery terminal to a back probe in the rr. Same with the output, 0.08volts dropped. About a year ago, when I first started working on this problem, I put on a new rr (I don't remember what brand) but the problem persisted. The stator is not wired directly to the rr. The wires go up somewhere then come back. The stator was putting out 71 AC volts, checked with all three wire combinations, at 5000 RPM.

[Nessism]

I recommend you rewire the system. Stator wires soldered directly to the R/R wires. R/R negative direct to the battery, or a solid frame mounting point - not to the battery box or electrical side plate. R/R positive out to the fuse box or straight to the battery with 15A fuse added. If that doesn't get the charging voltage up then your R/R is bad (assuming you are getting 71 VAC on each phase of the stator (you must check each phase separate).

[tom203]

Your stator AC test is good, so lose that useless stator loop going to headlight switch and back- it's just adding resistance, so eliminate it and see how your R/R does with it.

[Polluted]

I agree with shortening the wiring. I'll let you guys know how it goes. I think there might be some kind of poor connection at the headlight also. I I'm going to try to to check the positive side and the negative sides resistance. Thanks for the advice.

[BassCliff]

Greetings and Salutations!!

Hi Mr. Polluted,

These old bikes are notorious for corroded connectors and grounds. Clean them all, including the fuse box. (But I still think the stator is suspect.) Use this diagram for your stator-r/r connections:



If you have a stock OEM style (5 wire) r/r unit, disregard the "sense" wire connection to the tail light.

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Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...



Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

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Thank you for your indulgence,

BassCliff

[Redman]

I'm sure all the tests checked out. I have a little experience with electrics. The rr ground had 0.09 volts dropped from battery terminal to a back probe in the rr. Same with the output, 0.08volts dropped. .....

Good, so no problem in the positive wiring, and no problem in the ground wiring. So no need to rewire that.

...... The stator is not wired directly to the rr. The wires go up somewhere then come back. .....

Two of the stator leads would go directly to R/R, maybe thru a connector. One stator lead goes up to a connector and is jumpered over and comes back to R/R so go thru multiple connectors. The jumper is to substitute for a contact in the headlight switch that was there prior to 1980. So if you take that one stator lead to the r/r lead then you remove muliple connectors from that circuit.

Are any of the connections in the 3 stator leads getting warm? Feel the right next to the connector as compared to the wire a distance down the wire.

Most folks reccommend haveing the 3 stator leads wired directly connected to the 3 r/r leads, without any connectors. Can solder them for best connections, but then cant get apart for any further testing. Can also use wire nuts (small grey ones).

I suspect one of two things:
- bad connections in the stator to R/R leads.
- stator having a problem when under load.

....... I think there might be some kind of poor connection at the headlight also.........

Not related to your charging problem.
Actaully this would help your charging problem, less electrical load on the system.


.

[Polluted]

I got rid of all the connectors between the stator and the rr and soldered the w/g to the w/r, w/b to w/b and y to y. I also checked the headlight connection and it had a lot of corrosion. I know redman said this wouldn't contribute to my charging problem but after soldering the stator directly to the rr I now get 13.8V at idle and 13.5V at 5000 RPM with the headlight off. With the headlight on I get I get 13.5V at idle and 12.9V at 5000 RPM. I tried scrubbing some of the corrosion off but some still remains. I'm going to put new terminals on someday. I'm also beginning to think the stator might be the problem.

[posplayr]

I got rid of all the connectors between the stator and the rr and soldered the w/g to the w/r, w/b to w/b and y to y. I also checked the headlight connection and it had a lot of corrosion. I know redman said this wouldn't contribute to my charging problem but after soldering the stator directly to the rr I now get 13.8V at idle and 13.5V at 5000 RPM with the headlight off. With the headlight on I get I get 13.5V at idle and 12.9V at 5000 RPM. I tried scrubbing some of the corrosion off but some still remains. I'm going to put new terminals on someday. I'm also beginning to think the stator might be the problem.

Someone else here has similar issue. Charged good with lights off then nothing over 13V with lights on.

Probably stator but not sure is he ever reproretd back.

You also need to clean fuse box. Naval jelly will eat corroison then flow solderinto the joints. Check voltage drops between R/R and battery at 5000 RPM full load.

http://www.thegsresources.com/_forum/showpost.php?p=1648893&postcount=36

I suspect stator also but just ruling out a few things that need doing anyway.

[Redman]

I got rid of all the connectors between the stator and the rr and soldered the w/g to the w/r, w/b to w/b and y to y. I also checked the headlight connection and it had a lot of corrosion. I know redman said this wouldn't contribute to my charging problem but after soldering the stator directly to the rr I now get 13.8V at idle and 13.5V at 5000 RPM with the headlight off. With the headlight on I get I get 13.5V at idle and 12.9V at 5000 RPM. I tried scrubbing some of the corrosion off but some still remains. I'm going to put new terminals on someday. I'm also beginning to think the stator might be the problem.

Your prrevious testing and report shows no voltage loss from R/R- to battery+, and no voltage loss from r/r-to battery-.
SO it is not that you are loosing voltage somewhere due to bad connections from R/R to battery.
And you have not reported any heating in stator leads to r/r (and now have direct connections), so not loosing anything there.
So you are not loosing voltage anywhere, it is just marginal to begine with and goes down with load. More current flow, more voltage drop, less voltage. And yah, the stator is the begining of it all.

.

[posplayr]

Your prrevious testing and report shows no voltage loss from R/R- to battery+, and no voltage loss from r/r-to battery-.
SO it is not that you are loosing voltage somewhere due to bad connections from R/R to battery.
And you have not reported any heating in stator leads to r/r (and now have direct connections), so not loosing anything there.
So you are not loosing voltage anywhere, it is just marginal to begine with and goes down with load. More current flow, more voltage drop, less voltage. And yah, the stator is the begining of it all.

.

You have to keep in mind that just because there is no voltage drop doesn't mean the connections are good. There needs to be good current flow from a properly working system to actually test the R/R to battery voltage drops.

Assuming the stator is the issue, a retest of the connections after stator replacement would still be required.

[Polluted]

Alright a little more work here to do. I'll clean the fuse box and retest the rr to battery resistances now that I'm getting better voltage. I'll check them at idle and 5000 RPM. I went for an hour long ride today and the battery was fully charged at the end it so at least its functional now. But I want to hook up the windjammer. I'll report again next weekend. Oh yeah, the bike starts much better and accelerates smoother.