Topic: CB750 K6 Charging not charging

[scottly]

Don't bother with AC readings, just use battery voltage and how it changes as an indicator of charging.

[bigvalyeti]

Ok, also with my setup and this RR, before when it was charging, it use to take few minutes for the voltage to go up to 14.2V (even when revving it was going up progressively, like 2 minutes) and then it would stay there, is that normal behavior (in a lithium setup)
Or should the voltage just react instantly to revving and jump right away to 14ish

[bryanj]

Dont know, one reason i dont use lithium

[scottly]

Ok, also with my setup and this RR, before when it was charging, it use to take few minutes for the voltage to go up to 14.2V (even when revving it was going up progressively, like 2 minutes) and then it would stay there, is that normal behavior (in a lithium setup)

Yes, that is normal with either a lead acid or lithium battery. In fact, the lithium batteries take less time to recharge than lead acid.

[scottly]

Also, as the voltage on the battery goes up to 14.2V, the voltage applied to the white field wire goes down to the level needed to maintain 14.2V with the loads applied.

[Bodi]

There's a limited amount of amperage available from your alternator so it can't instantly brute force the battery to "full charge" voltage. So yes the voltage will creep up to the regulator target voltage. Fairly quick if you kicked it, considerably slower if you cranked a cold engine reluctant to fire for longish time - discharging the battery doing so.
Once the battery is recharged and voltage is at that target (14.2 or whatever) the regulator reduces field coil current to hold the voltage there, supplying just the power being used for ignition and lighting.
Electronic regulators that control field current do that either linearly or by PWM, adjusting a high frequency square wave's "on" time per cycle. PWM control produces much less heat in the regulator so it's the norm.
The OEM mechanical regulator has a type of relay that's voltage sensitive - at its set voltage it pulls a sprung bar to barely open a contact and reduce the power to the field coil through a resistor. If the voltage is much above the set voltage it pulls the contact bar in further and cuts off field power completely. This happens quickly, pretty much buzzing once recharging is complete.

[bigvalyeti]

If you have 13.2v coming out of the reg on the white field coil wire, and the battery reads 13.5v, it means the reg is calling for full charge, and if the field has the green wire grounded like normal, then it would point to the stator.

When you had 13.2 volts ongoing to the white field coil wire, it would have been the same as jumping the white field wire to battery plus, and you also measured the correct resistance from the white wire to battery neg, so you should have had magnetism. Since the voltage was jumping around, I would suspect an intermittent  connection either on the white field to white reg or the field green to ground. With the key on, and headlight on, measure the voltage from the battery negative post to the head of an screw on the engine, and then to the green field wire: it should be zero in both cases.

Okay so I have 0.03V between battery negative terminal and bolts on alternator, normal I’d say.
And 0.2V between battery negative terminal and green field wire, would that be problematic?

[scottly]

And 0.2V between battery negative terminal and green field wire, would that be problematic?

Not necessarily a problem. Exactly where are you checking the green field wire?

[scottly]

Also, where was the bad connection on the stator phase before?

[bigvalyeti]

First picture is where I had the 0.2V potential difference

Second picture is the third phase cable that was forgotten in the beginning, the bike was ridden without it for circa 30km

[scottly]

Is the yellow wire at the bullet connection under the sprocket cover?

[bigvalyeti]

No it was basically in a 8pin block connector, not under the sprocket cover.
In the connector there are neutral switch, oil pressure switch, white + green field coil wires, and the three phase wires (one was misplaced in the empty spot on one of the connector side

[scottly]

You might want to check the bullet connections under the sprocket cover, since nothing seems to be consistent. The wires exit the alternator cover and are hidden under the shifter cover with the ends under the sprocket cover. The field is on the top, and the stator is on the bottom:

[bigvalyeti]

Yeah the bullet connectors are fine.
I tested also checking the voltage without the relay, directly plugging black regulator wire to battery positive via a fuse and the charge is capped at 13.5v doesn’t go higher…
I noticed the case was magnetized all along.
Maybe the RR got damaged while not plugged correctly, would that be possible?

[scottly]

When this first started and the voltage never went over 13.5 volts, there was a phase missing. After fixing that, the voltage went to 14+, until all of a sudden it dropped to 10V, and then the bike died. Now, it's back to 13.5V.
You can test the rectifier with a meter. Give me a minute....

[scottly]

I gave step-by-step instructions on testing the rectifier in reply #331 on this thread:
http://forums.sohc4.net/index.php/topic,32093.msg2263875.html#msg2263875

[bigvalyeti]

Yes I did had a forward and reverse bias normal test. But I thought maybe it fucjed the regulator part of it… I don’t know really

[scottly]

No it was basically in a 8pin block connector, not under the sprocket cover.
In the connector there are neutral switch, oil pressure switch, white + green field coil wires, and the three phase wires (one was misplaced in the empty spot on one of the connector side

What is the blue wire, and what are the 3 red wires in this pic?? What all has been changed on this bike?

[bigvalyeti]

lol, the big blue wire is the main ground hooked up on the frame on the side of the bike (I got the lithium battery right under the seat). The red wires are the three fuses I got in a 3d printed fuse box.
Electrically, it’s the same circuitry except the added relay for the regulator, Dyna s + coils, the RR itself and lithium battery.

[scottly]

If the field is being magnetized, the regulator is working, at least to some extent.