Topic: More charging issues!

[toread]

Hi all,

I posted a little while back when I had problems sorting out a new reg/rec install. The bike would drain its battery with the key out but would charge perfectly when running.  In order to keep it on the road I had to constantly detach the negative terminal from the battery.

Turns out the person who sold me the reg/rec unit inadvertently sold me a unit from a bike with a permanent magnet alternator from a later series Honda.  My bike is a 78 cb550 four k with a field coul rather than a magnet. 

I installed a new used unit and followed the wiring diagram from the 650 the new unit was off of.  No charging.  So I checked and double checked every connection to make sure I had done it right, and I am fairly sure it's fine.  Eventually I caved and bought a new (used, but in great shape) alternator assembly. The field coil and the stator coil are in good shape and I installed the without any hiccups. 

I fired up the bike and tested the battery and voila! It was showing the appropriate voltages at different rpms across the battery terminals.  I was elated, it had been about a month of tooling around and humming and hawing over the charging system. 

I took it out for a ride the other day and got about half an hour before it died. I had to haul it into a friends garage and pick it up later. I got it home expecting a completely different problem, because by this point I had changed the whole charging system, but I checked the battery anyways and it's no longer being charged at any rpm. 

It shows 12.5V approx at any given rpm, no fluctuation at all.  I have taken the charging system apart fully again and double checked everything, it all seems to be connected fine.  I have tried running through the electrosport fault finding chart again, and it doesn't register 50 AC V accross the three yellow wires from the stator, but how could the stator have failed in three days of sitting in a garage without running ( three days from appearing to be fixed, to dying on the road in half an hour).  Is there something screwy that could cause the stator coils to be fried with how I've wired it? Is there maybe a bad ground somewhere? The battery needs to be replaced, but even with a bad battery you should still be registering a change in voltage accross the terminals at higher rpms...

Any help would be appreciated, I am at the end of my rope with the charging system in this bike, and am a couple days from giving up and taking it to a garage, something I don't want to do, and can't really afford.

Thanks in advance.

[TwoTired]

The field coil needs to be electrically energized to make a magnetic field.  With no magnetic field, the stator can make no voltage/power at any RPM.

Check to see if the field coil is getting a voltage across the white and green, before even attempting to measure the stator output.

[L3niin]

you should check all your wireing i had the exact same problem ..
 one wire can mess up your day ..

one wire that i couldnt even tell it was not properly conected .. mess my day up

[scottly]

A quick check of the field is to see if it is magnetized when the ignition switch is turned on.

[toread]

I've got 10V accross the field coil lines. I've also tried wiring those two lines direct to the battery in order to bypass the reg/rec and still nothing...

What would the symptoms be if the ground off the reg/rec was bad?

[scottly]

The wrench wouldn't stick to the alternator housing.

[Rgconner]

The wrench wouldn't stick to the alternator housing.

Won't on my 75 cb550, and my charging works fine. Just tested it.

Not sure this is a good test, maybe with the engine running it would stick, dunno. did not start the engine, I got the tank off it right now.


Check the voltage drop across the ignition switch. A big drop means you might benefit from adding a relay to bypass it.

[scottly]

Any magnetic pull at all on your 550 RG? It shouldn't make any difference if the motor is running.

[trueblue]

Have you checked your brushes, it sounds like they could be worn down and giving you the intermitant (sort of) charge issue.  If you are brave you can get a piece of wood and tap the alternator housing to try and get contact on the brushes, a hammer handle would do the trick, but don't tap too hard, you could break something.  I would try this if it starts working I would replace the brushes, if it doesn't I would still check them.

[toread]

Scottly, I will go out and try the wrench test today to see if the field coil is powered, thanks for the tip.

Trueblue, this model doesn't have any brushes, it uses the rotor to distort the magnetic field from the field coil to the stator coils.  Basically just spinning around in between the two units causing AC current in the three yellow wires of the stator.

I'm not sure if there is anything that can go wrong intermittently in that system, any ideas? It's definitely puzzling to have it charge one day, and nothing the next...

[Rgconner]

Any magnetic pull at all on your 550 RG? It shouldn't make any difference if the motor is running.

Very, very faint. Would not hold up a 10mm Craftsman, not even close.

No fixed magnets, and electromagnets are not that strong at 10 to 12 volts.

[TwoTired]

I've got 10V accross the field coil lines. I've also tried wiring those two lines direct to the battery in order to bypass the reg/rec and still nothing...

Why only 10V?  Why doesn't it get full battery voltage?  Or, why is the battery only putting out 10V?

What would the symptoms be if the ground off the reg/rec was bad?

For the stock electromechanical regulator, the regulator couldn't do it's regulation job.  For other regulators, it would depend on the internal design factors.

Lets' get some fundamentals established.
The field coil has two connections.  One lead connects to the engine/frame and battery NEG terminal.  Check that pathway for solid continuity.  Or, check for low voltage loss in that path when the coil is energized.
Next do the same for the White wire connection to the field.  The regulator should feed the white wire full battery voltage, whenever the battery voltage is lower than 13.5V-ish.  Check for voltage loss between white wire and battery POS terminal.

You could also insert an ammeter between the white wire and the voltage source.  A 5Ω resistance fed 12V must draw 2.4 A.  (Ohm's law)
If the field coil draws that amount of current, it MUST make a magnetic field that will reach out to the stator windings.  When the rotor spins, it makes the magnetic field fluctuate, which induces voltage in the stator windings.

Are you measuring the stator windings while they are connected to a known good rectifier, or just the free unconnected yellow wire ends?
Are you using the DCV scale on the yellow wires or the ACV scale?

Cheers,

[bollingball]

Just a little tip. You will have a stronger pull on the wrench at the head of any of the three screws.
Ken

[toread]

Thanks two tired.

I read in the electrosport fault finder that 10V was ok, when I tested, I got roughly ten, but I also took two wires and connected positive to the white of the field coil, and negative to the green to bypass the regulator. Still no working charge.

I also tested the yellow wires for AC Vs under this condition and received readings of only 10acv across each wire pair. I hear it should be more likely 50 acv.

I'm going to go back out to the garage right now and retrace my steps. I will report back with specific numbers.

When I put the new reg/rec on I tried to follow the 650 wiring diagram from the bike it came off of. So that means white from theRR goes straight to the white from the field coil, and one of the blacks from the RR goes straight to the green wire from the field coil, no grounds or anything in between. This is different from the cb 550 wiring diagram where the green from the field coil is grounded.

I'll also try to wire the green from the new RR straight to a ground and bypass the wiring harness altogether to make sure the connection is good. I still can't understand why it would Work and then stop working from having it wired and then putting the harness back on the frame. (now with the harness off it still doesn't work)

[toread]

Ok, there is a magnetic field on the alternator housing, but I have a 3V drop from the battery to the black and white wires out of the RR that power the field coil when the bike is off, and a 4V drop when the bike is running. I'm only getting 8V to the field coil, the battery is a bit low from all the testing, so I don't know if that would throw off the readings.

When the bike is running, I get roughly 12.6V accross the battery terminals, at 5000rpm. Doesn't change much at lower/higher rpms. I've read that it should be above 13.5V at 2500rpm and below 14.5V at 5000 rpm. The battery is trashed from all of the times it has died due to this electrical issue, could all of these weird issues be due to a crappy battery?

[TwoTired]

The battery charge state will dominate the voltage.
Even a good charging system will show low voltage at the battery when the battery is depleted.  That's why you check the charging system with a known good full charged battery, to see if the charging system is capable of maintaining it.

I think the 650 regulator needs independent control of both field coil wires, which it can't have on Cb550, as one end is always grounded.  I've seen reports of the 650 regulator being damaged if the outputs are grounded.  (I'm always able to make the stock regulator work for me, so I use what works for me.)  I found a vreg schematic (below).  If you have grounded the F terminal of the Vreg and applied 12V to the B terminal, diode D1 or transistor Tr3 may not have survived the punishment.

To isolate the regulator as a source issue, run wires from the battery directly to the field coil wires.  When you rev the alternator, it should allow the battery voltage to creep upwards (slowly if depleted).  Since you've will have removed the smart bits (in the vreg) to protect the battery from overcharge, you will need to monitor the battery voltage and discontinue charging it if the voltage climbs above 14.5V (depends on battery charge state).

A good but depleted battery won't be charged up to 14.5v unless the alternator maintains 5000 RPM for about 10 hrs. Obviously better charge state batteries will gain voltage faster than 10 hours.

Good luck!

[scottly]

Ok, there is a magnetic field on the alternator housing, but I have a 3V drop from the battery to the black and white wires out of the RR that power the field coil when the bike is off, and a 4V drop when the bike is running.

You mean if the voltage at the battery is 12V, you read 9V at the black wire??? That's a huge drop. You have resistance somewhere between the battery and the black wire. Take a hard look at your fuse box, for starters. Clean the fuse holders. Could also be in the ignition switch, or corroded wire connections, or a combination of all three?? 

[toread]

Thats my next task I guess.  I wasn't sure what kind of voltage was required to power the field coil.  Could a corroded connection or dirty connection be the cause of the intermittent charging?

I'm ordering a new battery as well, to make sure that it isn't messing up any readings.  Its something that needs to be done, I was just waiting until I had fixed the charging issue... Looks like when it comes in either today or tomorrow, Im pulling the wiring harness off again and checking everything.

Ill let you know what I find, Thanks for all your help!

[toread]

UPDATE:

I took the wiring harness off again and inspected every single wire, and all the connections that I could (some of the connectors inside the plugs are hard to check).  I had significant buildup on the turn signal relay plugs, so I cleaned them off and plugged them back in.

I also installed a brand new fully charged battery.  With everything still apart, and with the plugs all out of the actual harness, I dummy fit all the connections together and fired it up.  Everything seemed to be working, I had 13.6-13.7 at 2500 rpm, and 14.4 at 5000rpm going up to 14.8 if I applied the brake to engage the brake light.  Satisfied that something I did had fixed the problem, I carefully put everything back together being sure not to miss anything, and I started it up again. For a second everything seemed to work, and then I got lower and lower voltages accross the terminals, and now when I start it up the battery sits at around 12.8-12.9V regardless of what rpm I'm sitting at.

So something in between having it apart, and packaging everything back up I have a problem.  I don't have any exposed wires in the loom and I know I put everything back together as before...

Any suggestions?

[toread]

So after cleaning all the connections up and testing it with the wiring harness connected but not mounted, I got proper charging voltages accross the batt terminals. After putting it together it stopped working, so I just took the harness off again, and kept all connections clear from the frame and I got 13v at 2500 rpm and 14v at 5000rpm, which isn't quite right but it's enter than before. Is that enough to charge the batt while running and If so, how do I mount my wiring harness without cause a problem?

[TwoTired]

If you are checking the charging system voltage with a depleted battery, you won't get relevant voltage readings until after running the engine at 5000 RPM for about 10 hours (assuming the charging system is good).

The battery neither depletes quickly or recharges quickly.  That's what makes it useful.

To check the charging system function you must have a known good, fully charged battery.  A depleted battery will make even a good charging system look bad or deficient.

[scottly]

To rule out battery charge issues, go back to the voltage drop issue you reported earlier. Connect the red meter lead to the + battery terminal, and the black meter lead to the black reg lead. This will read the drop directly. With the ignition switch on, motor not running, the meter should read no more than 1V; wiggle the various connectors while watching the meter, and see if it fluctuates.

[toread]

Hey scottly,

Thanks for the response, and sorry for the delay in my reply, I had to go out of town for a bit. I'm working on the bike all night and am hoping to crack this mystery.
There are two black wires from the reg/Rec unit, but I tested with the black regulator wire on it, not the power return for the field coil.
With the red lead on the + terminal and the black to the black wire on the regulator, I read 11v or thereabouts. Does that mean I have a one V drop?

[scottly]

Hey scottly,


With the red lead on the + terminal and the black to the black wire on the regulator, I read 11v or thereabouts. Does that mean I have a one V drop?

That means you have an 11V drop. Is the black wire you are measuring the black wire on the stock harness?

[toread]

The black wire is the black wire from the original regulator. My understanding was that it essentially keeps a finger on the pulse of the voltage throughout the system.

It connects with the black wire from the turn signal relay. That connection looks clean and had some Vaseline on it or something.