Hi again all,
Continuing to check out stuff that needs attention on my new-to-me 2005 GS500, and something is up with the charging system. I'm 100% sure the battery is good (for now), it holds a charge and I had it load-tested. I went through the whole charging trouble tree elsewhere on here, and it pretty much passed everything. There are only two things that are iffy:
-At 5000, charging system voltage is right on the low end of acceptable at 13.5
-One out of the three stator coils measured slightly low (69 volts)
Is that low enough to cause trouble? The resting voltage of the battery after trickle charging it is 12.8, but the bike itself only charges it to something like 12.5. Dash lights are on the dim side, which was my first clue to something being up ... 2nd symptom of weirdness is sometimes the tach doesn't move at ALL for a couple seconds after starting, then it fires up and tracks accurately.
Hmm..
Check and clean ALL connectors in the charging system, including the battery terminals then...
Whats the charging voltage at:
2k rpm
3.5k rpm
5k rpm = 13.5 you said
7k rpm
The charging voltage should steadily rise from 12 to 14v when going from 2k to 7k. If it doesnt, there is a problem.
Are you sure the battery is good? If it is, why trickle charge it?
Check battery voltage now.
Check battery voltage in 6 to 12 hours or more while it has been siting. Did it drop? If so how much?
Voltage drop just sitting means bad battery.
Good batteries do not need to be on chargers.
Clean all connections.
Possible the voltage regulator is going out. (Providing the battery is good). A bad battery can pull down the voltage from the regulator.
@adidasguy:
I already did those things. As stated, the bike will not maintain a full charge by itself, just mostly full. I trickled charged it, left it OFF the charger for a day, and the resting voltage THEN was 12.8. "Load-tested" meant that I brought it somewhere that had a battery tester ... I guessed the battery at 160 CCA (it's a Yumicron, probably more than that) but it at least tested good for that. I'm pretty sure the battery is good. I'm guessing there's no way to test the regulator independently of the rectifier?
@vinny:
At 2K I think it's at 13.8 ... somewhere between 2K and 5K I think it even crests 14V ... then it falls back down to 13.5 when it approaches 5K.
As others have said before, check all connections. Mine has been charging a little sluggishly lately. Gave it a wash earlier and when I was replacing the seat I noticed that the in-line fuse between my R/R and battery has clearly been hot and even started to melt slightly. I've cleaned it up and the charging seems to have improved already, so hopefully I have dodged a bullet there. Another thing I have found is that the charging actually drops off at higher revs and the "sweet spot" for charging is at about 2-2.5k revs (that could have been the dodgy fuse holder though)