| Author | Message | ||
     Dsword |
OK, I searched the vault and just got more confused... Battery slowly dies while riding, is the issue. BRAND NEW battery, cuz I thought that was the problem (no service records). Before starting, battery voltage is 12.5 volts, after trickle charging for a couple hours. Voltage at battery when first started is 14 volts dc at idle. At 3000 rpms, drops to 12.5 volts dc. Then - After about 20 seconds at idle, that too drops to 12.5 volts dc, basically what power is available in the battery. Checked stator output at idle is about 28 to 30 volts ac. At 2000 to 3000 rpms, output climbs up to about 45 to 48 volts ac. It's not an instant jump, but climbs right up. Checked output from voltage regulator - at idle it's about 3.5 volts dc. At about 3000 rpms it drops to 2.3 volts dc. Shouldn't the regulator be putting out 14 volts? maybe not when disconnected from the battery? Sounds to me like the voltage regulator gone bad... Any experts available to confirm or disagree? Thanks! | ||
| Froggy |
Check the 77 connector first. Do a search on here, plenty of threads on it. | ||
| Ft_bstrd |
That sounds about right. If your stator output is consistent, but you VR output isn't, the VR is probably the problem. You've checked your 77 connector plug? | ||
| Dsword |
My 77 plug is slightly melted\deformed. I read the document by Rays. I can clean that up, no problem, but is the regulator only supposed to put out 2 to 4 volts at the plug when disconnected at the 77 plug? | ||
| Reepicheep |
With the 77 plug disconnected, the only power is from the battery... and measuring it at the 77 connector is measuring what the battery would be feeding the stator. I'm surprised it sees *any* voltage when things are working right... unless you want your stator to be a transmission pre-heater... | ||
| Dsword |
Saaaaweeeet! Cleaned up the 77 connector. Reconnected everything. Started 'er up and there's a constant 14.3 volts at the battery at anything above idle. Done deal and FREE. This forum is awesome. Thanks Froggy and Ft_bstrd! | ||
| Dsword |
Check that. Not exactly free... $92 for an unnecessary battery. My bad. Maybe it'll fit in my Road King??? | ||
| Reepicheep |
Oh, and how on earth did you measure the output from the VR? The output from the stator is the input to the VR is the input to the battery. If you disconnect the VR from the stator to measure the VR output, you also disconnected the VR input, which makes output measurements fairly useless. It would be good to confirm your stator output is still high after the 20 second idle when the bike is no longer charging the battery... a bad VR is plausible... it takes it 30 seconds or so to overheat while operating normally, and something internal goes to a dead short and stays there. Is the VR getting really hot? Hmmm... hadn't thought of that before. I'll have to throw an IR thermometer on a good VR and plot it's temperature change from cold while idling. That could be a handy dandy diagnostic... | ||
| Dsword |
I checked the VR output with the stator reconnected. So voltage was feeding the VR from the stator through the VR to the disconnected 77 connector, right? Not sure if it's getting hot, didn't feel it. Only ran the bike for 15 seconds while I metered the VR side of the 77 connector. | ||
| Dsword |
Heck - Forgot to thank Rays for the document explaining the 77 connector! Good stuff. | ||
| Rays |
Dean - appreciate the thought. Glad to see it helped you out. BTW - with the 77 connector disconnected the output of the VR is zero. I haven't dissected one yet to see the actual circuitry to understand why but I did notice that when I was chasing the original 77 failure a couple of years ago. | ||
| Dsword |
Maybe I didn't look close enough and the meter was displaying milliVolts? | ||
| Rays |
Dean, sorry - it may well be a very low voltage that probably varies from VR to VR. I should have said close to zero rather than imply absolute zero.  | ||
| Dsword |
Ah, very good. Had me worried a bit. All I know is that the volts now hold at ~14.3 or so at any rpm off of idle. Your instructions were excellent, told me exactly what to look for, great job. If it acts up again, I'm going to either find a better connector or solder the wires direct to remove the weak link... | ||
| Reepicheep |
Excellent! Thats what I am going to do if I see any 77 connector problems... just solder the wires. |
