Topic: For SCIENCE! (weak charging)

[RandomOrbit]

And you’ve put in new regulator and rectifier?

yep. Like I said I'm not sure what's going on, but it maybe the battery was not fully charged or is no good. It's on the charger again now, and hopefully in a few days it will test better. If not we'll start with a new battery in the spring and go from there.

[TwoTired]

Did you follow the process I posted earlier?

[RandomOrbit]

Did you follow the process I posted earlier?

Up to a point. Based upon readings of the rectifier diodes, I decided it could use replacing. Since the new unit is a combo, that rules out anything with the regulator. That brings me down to step J, BUT I'm now thinking step A might be an issue. My battery SEEMED pretty good after charging for 2 days, and SHOULD be pretty good since it's relatively new, but at this point I'm thinking I may have been mistaken.

So at this point I feel I need to verify the battery really is good before I can go any further.

[seanbarney41]

Forgive me if you have, I can't keep track of what everyone has and hasn't done...but, you have pulled the sprocket cover off and cleaned and inspected your stator wires?  There are bullet connectors in there that live a very hard life, particularly so on your bike, judging by your pictures.

[RandomOrbit]

Forgive me if you have, I can't keep track of what everyone has and hasn't done...but, you have pulled the sprocket cover off and cleaned and inspected your stator wires?  There are bullet connectors in there that live a very hard life, particularly so on your bike, judging by your pictures.

No, but I will. I was just in there today checking the neutral switch wire. I cleaned out quite a bit of sludge. I'm sure those bullet connectors could all use a good thorough cleaning.

[Spanner 1]

15 days , so far. It never ceases to amaze me how folks come on wanting advise to fix a problem and freely get expert advise from folks with long track records of helping SOHC4 owners with all kinds of problems resolve them. But no, not gonna do what I have been advised.... prefer to post away here for ever ( 'cos I like the sound of my own voice ) more than fixing my bike ( secondary ).

[Bodi]

It's a simple system. Experience has taught that the stator and field coils are very reliable excepting physical damage.
The most common charging problem is from the wiring harness. Not the wires, the connectors and switches - they get corroded and a voltage drop develops. On higher current wires the corroded connectors will then overheat and get even worse with more corrosion, more voltage drop, and maybe the female side's metal will heat up enough to anneal and lose its springiness.
Cleaning all the bullet connectors M and F sides, replacing any annealed females and any ends that the solder has melted out of, then reconnecting with a dab of dielectric grease can resolve many electrical gremlins. The stator and field coil connections under the sprocket cover are very prone to decay as they're more "in the weather" and subject to engine case temperature. I often delete these bullets, soldering the wires together and sealing with glue core heatshrink tubing - makes removing the alternator a bit less fun but the wires go to the engine connector so that isn't much harder. And alternator coil removal is rarely needed.
The battery ground cable is also vital, must be good contact between the ring lug and bare frame metal. The opposite side of the frame tab where it touches the engine should also be bare steel.
The charging system charges the battery... so battery problems will frustrate troubleshooting. It must be in very good condition and fully charged to test the regulator function.
The rectifier is fairly dumb and testing it is a bit tedious but easy with a multimeter.
The regulator is not very smart but testing it on the bench requires a variable DC power supply... and testing on the bike works pretty well.
One key is the voltage drop between battery "+" and the black wire on the regulator. Just measure voltage between these points, either with key and lights ON or with the bike running with lights on. It really should be less than 1 Volt, around 0.5V is normal with a good harness. High wattage headlights will increase the drop. A relay can be added to connect the regulator directly to battery "+" when the key is on - to ensure accurate voltage sensing in the regulator. Also, the field coil is powered from that black wire and any voltage drop equals less coil current and less magnetic field to generate electricity in the stator coils.
Once running with a fully charges battery the battery will be discharged and discharging when RPM is below 3000 or so. If the battery was fully charged before testing and the engine started with the kickstarter... the system should fully recharge it within a few minutes and battery voltage should rise to ~14.5V then not get any higher. At idle the battery voltage will slowly drop as current is drawn from the battery to make up the difference between low RPM alternator output and the electrical load of the bike.

[BomberMann650]

The voltage dropped after the combo unit install.

This is why i like the Oregon Moto Components. 

[RandomOrbit]

The voltage dropped after the combo unit install.

This is why i like the Oregon Moto Components.

That's actually a big part of why I suspect the battery. I was able to charge it up more 2 weeks ago after I gave it two days on the maintainer and got it up to 14+ volts which settled down to 13.2 after taking it off the charger for a few hours. It was holding at 12.25 volts on the bike two weeks after having fully charged it, but it didn't have enough oomph to spin the starter very well or blow the horn. Working on the electrics on Saturday meant a lot of running the lights without the engine running and that depleted it further. I pulled it from the bike Friday after work charged it overnight before starting work on it on Saturday afternoon, but it wasn't much better than when I pulled it from the bike Friday night.

It's been on the maintainer now since last night, but when last checked this morning was only at 12.76 volts. There's no good riding weather in the forecast, so I can give it a few days and see if the "reconditioning" mode of the maintainer can improve it, but if I need a new battery I'll want to wait until spring. No point in letting a new battery sit around all winter.

[BomberMann650]

That could be the case.
Such a shame motorcycle batteries fail so easily.  There has GOT to be a better energy storage alternative!
Future time travelers please tell us if there is!

[TwoTired]

Many years ago my 84 toyota burned out the low beam.  I replaced it with a new one.
However, my problem with tossing items that are still useful kept the now high beam only lamp in my garage.  It turns out to be useful at rudimentary Battery testing, as it draws 5-6 amps.  If a battery will light that lamp and hold the voltage above 11.5 for a minute, it is worthy to place in a bike.  It's not a full load test.  But, it's been a pretty good indicator.  I will point out that the standard 50W SOHC4 head light draws about 4 amps.  And the entire bike with lighting draws about 10A.   These are also reasonable load tests.

A battery loses plate material as it discharges.  Recharging puts the material back.  But, the plate separator design determines how well the metal gets put back where it came from.  Many charge/discharge cycles can leaves holes in the plates, or even cut the plates in two pieces, which reduces plate area available.  When the plate area is reduced, so is the current output capability of the battery.  In other words looking at voltage potential alone, does not guarantee that the battery can deliver rated current.  Placing a load on it and have the voltage drop below 10V, generally means the plates have been eaten by the acid into a shape that can't support the current demand.

Of course there are marginal conditions that can fool the simple tests.  But, sometimes it can save you time and effort on a lost cause.

Cheers,

[Mr. Mike]

“12.5 volts and not spinning the starter very well or blowing the horn.”
 I’d suspect the battery. What type are you using? Lead acid...sealed?
I too placed a small digital meter up front to show my state of charging. Earlier this year I was experiencing a low state battery too often, like a no start (except kick) after lengthy rides. The little volt meter showed only 12.8 max within my system all the time.
Turned out to be dirty contacts at the regulator. It’s nice to see it vary from 12’s to upper 13’s.
Just my experience.