Intermittent charging mystery

Supercat

Supercat

Joined
Aug 23, 2017
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Hey folks,

I have continued to ride my bike constantly since making it home from Nova Scotia last week. Even did a bit of moto-camping last weekend. I have not yet tackled the charging issue, and I thought it might be worth posting the relevant clues that have presented themselves thus far before diving into it:

- the last 3 mornings it seemed to charge perfectly during the first ride of the day, and then to not charge for the remaining rides;
- during the first breakdown in NS, we found the wire from the stator to the assimilator had been rubbed raw against the gas tank. This was fixed, however, I wonder if this might have affected the assimilator. Can I test this by simply unplugging this wire from the assimilator and running to bike and testing voltage?
- I recall last year that I blew a fuse and suspected that it had to do with my rare use of the horn that day. I expected that had to do with the horn button area itself, but I had that all apart recently and it doesn't seem to be. No idea if this is related, but it seems likely that there is still an intermittent short in the horn circuit somewhere.

I feel like this is probably to do with either a short or a bad ground somewhere, just because when it is charging everything seems to be working fine. I did do the two stator tests in NS with the bike not running and everything checked out. We checked stator output at one point but it wasn't me reading the meter at the time so I'm not exactly sure of the result, but it seemed to be working fine.

My plan is just to take the tank off again when I get time and to go through the wiring carefully to see what I can find. And I may try disconnecting the assimilator and running it to see what happens. The red light is working fine, though it did not turn on when the battery dropped below 9 volts leading to the original NS breakdown...

Any thoughts would be most welcome. Thanks!!

J
 
Supercat said:
Hey folks,

I have continued to ride my bike constantly since making it home from Nova Scotia last week. Even did a bit of moto-camping last weekend. I have not yet tackled the charging issue, and I thought it might be worth posting the relevant clues that have presented themselves thus far before diving into it:

- the last 3 mornings it seemed to charge perfectly during the first ride of the day, and then to not charge for the remaining rides;
- during the first breakdown in NS, we found the wire from the stator to the assimilator had been rubbed raw against the gas tank. This was fixed, however, I wonder if this might have affected the assimilator. Can I test this by simply unplugging this wire from the assimilator and running to bike and testing voltage?
- I recall last year that I blew a fuse and suspected that it had to do with my rare use of the horn that day. I expected that had to do with the horn button area itself, but I had that all apart recently and it doesn't seem to be. No idea if this is related, but it seems likely that there is still an intermittent short in the horn circuit somewhere.

I feel like this is probably to do with either a short or a bad ground somewhere, just because when it is charging everything seems to be working fine. I did do the two stator tests in NS with the bike not running and everything checked out. We checked stator output at one point but it wasn't me reading the meter at the time so I'm not exactly sure of the result, but it seemed to be working fine.

My plan is just to take the tank off again when I get time and to go through the wiring carefully to see what I can find. And I may try disconnecting the assimilator and running it to see what happens. The red light is working fine, though it did not turn on when the battery dropped below 9 volts leading to the original NS breakdown...

Any thoughts would be most welcome. Thanks!!

J
Click to expand...
Simply remove the assimilator and be sure the wires don't touch anything. The assimilator is absolutely NOT needed for operation. It's only job is to tell you if the stator is producing AC power - it DOES NOT tell you that the battery is charging or anything about the charging circuit.

With the wire from the stator to simulator grounded other things are probably damaged. The stator could be damaged depending on your charging system components (OEM setup, aftermarket regulator, single or three-phase stator, etc.)
 
The alternator puts out AC before the rectifier converts it to DC, so when testing the alternator directly have the meter set to AC V not DC. Some digital meters will not like the emf from the spark plugs but most modern ones will be ok, if not find a cheap analogue meter. The AC V will vary a lot as the revs rise as there is no regulation until the Zener or the regulator plus to get 12V DC you need say 15V AC as its a sine wave form.

A small short that is not enough to blow a fuse will also drain a battery even if its being charged. To test for a short then swap the fuse for a 12v main bulb and see if it lights with the bike turned on, engine off. If you are running points then that will be a draw but any EI box will turn off after a few seconds when it realises the engine is not running.
 
The workshop book describes several test procedures for alt, rec, zener.

One i believe is to use a meter to check for AC getting past the rectifier...simple put the meter leads on the battery or one on batt, one on frame ground (so if positive earth bike, use neg batt post). Then check for ac while reving engine...should be none. Replace rectifer if detected.

Next check dc volts as you rev engine...should not see more than 14.5-15.2...else zener not limiting volts correctly. Since positive earth zeners are as rare as hens teeth these days, only recourse is to update with modern reg/rec like Podtronics or the Trispark box.

You can also test the 2 MC capacitor on the bench. Connect it to your battery (be sure positive terminal to positive battery post etc.). Then disconnect it and wait a few minutes...then put test probe/test light leads on the capacitor to check for 12 dc output...should still have a charge for something like 5 minutes after batt removed.
 
I have been carrying the multimeter and checking voltage routinely. It still seems to charge when cold, and to very slowly drain when warm. I have checked voltage when running, and first thing in the morning it is getting more voltage than in the sitting battery even at idle. With revs it goes up to over 13 at around or just over 2000 rpm. Not sure how long this lasts, but when I start the bike again after a ride it is at or below non running battery voltages and revving makes no difference. Does not increase voltage.

I haven’t yet had time to dive into proper testing, but I did check ac at the two alternator wires while running yesterday. I did this during a later in day run, so it was not cold. I did not disconnect the wires, just stuck multimeter leads on them. Measured at just over 5 volts. I thought it was supposed to be 25 or 30?
 
Supercat said:
I have been carrying the multimeter and checking voltage routinely. It still seems to charge when cold, and to very slowly drain when warm. I have checked voltage when running, and first thing in the morning it is getting more voltage than in the sitting battery even at idle. With revs it goes up to over 13 at around or just over 2000 rpm. Not sure how long this lasts, but when I start the bike again after a ride it is at or below non running battery voltages and revving makes no difference. Does not increase voltage.

I haven’t yet had time to dive into proper testing, but I did check ac at the two alternator wires while running yesterday. I did this during a later in day run, so it was not cold. I did not disconnect the wires, just stuck multimeter leads on them. Measured at just over 5 volts. I thought it was supposed to be 25 or 30?
Click to expand...
Unless you are measuring the wires unconnected then its telling you nothing.

Something is failing as it warms up, so start with an AC test on an unconnected alternator when cold and then when warm. Then do that at the next part of the chain eg rectifier and then regulator if they are separate. Or do a cold test in sequence, ride it and then warm test in sequence.

Messing about 1/2 cocked will not find the issue, steady and methodical will.
 
Supercat said:
I have been carrying the multimeter and checking voltage routinely. It still seems to charge when cold, and to very slowly drain when warm. I have checked voltage when running, and first thing in the morning it is getting more voltage than in the sitting battery even at idle. With revs it goes up to over 13 at around or just over 2000 rpm. Not sure how long this lasts, but when I start the bike again after a ride it is at or below non running battery voltages and revving makes no difference. Does not increase voltage.

I haven’t yet had time to dive into proper testing, but I did check ac at the two alternator wires while running yesterday. I did this during a later in day run, so it was not cold. I did not disconnect the wires, just stuck multimeter leads on them. Measured at just over 5 volts. I thought it was supposed to be 25 or 30?
Click to expand...
The alt should be throwing out loads of ac that rapidly go up with rpm...15-35 VAC should be easy to see.
Put the multimeter in Ohms mode and check for resistence through the two alt wires (disconnnected). The book gives a spec for this reading I believe. Obviously if no continuity/open circuit is found, theres your problem. Could be a broken wire/connector before alt itself (potentially repairable), or a broken wire inside the atl windings (needs a new one) .
There are also reports of the rotor itself coming apart as magnetic sections break free of their surrounding material, or the magents loose their magnetism.
 
Hey all,

Thought I would post a quick update. Still riding with the intermittent issue. I just charge the battery every few days, and it seems to be fine for commuting to work and the occasional longer ride. I've gone 300 km or so in a day since getting home from the Nova Scotia trip with no problem (with a charger in a saddle bag and a place to charge halfway along if necessary). I did manage to find 5 minutes one day last week to put a light bulb where the fuse normally goes as suggested above. It does not stay on when the key is in the on position. A short seems less likely now.

I notice that when the bike is charging (it seems to be when the bike is cold at the beginning of the day) that there are more than 13 volts at the battery and accessory plug at idle. This is higher than I would have expected. This makes me suspect the regulator, but I'm obviously not sure.
 
Supercat said:
This makes me suspect the regulator, but I'm obviously not sure.
Click to expand...
Only a concern if 14.5+V, on a car with a larger battery 16V is not unknown. A battery has to be charged at a higher V for the energy to be forced in, remove the charger and the V will gently drop to 12.7V if no load is connected.
 
I highly recommend that you toss the assimilator and install a voltage monitor in the panel. The stock setup tells you nothing other than AC is coming out of the stator. A voltage monitor is a real volt meter in a light and looks at the DC voltage, the actual stuff that's important.
Check out this one: http://www.sparkbright.co.uk/sparkbright-eclipse-battery-voltage-monitor.php There's a video on the site so you can see one in action.

It's the one that's worked perfectly in my bike for years. In bright sun when it's green it's hard to see but no matter, no light means all is well. When amber or red it's visible in all light conditions. It drew my attention immediately to a stator problem.

There are others available, I can just recommend the Sparkbrite as it's worked perfectly for me.
 
JimNH said:
I highly recommend that you toss the assimilator and install a voltage monitor in the panel. The stock setup tells you nothing other than AC is coming out of the stator. A voltage monitor is a real volt meter in a light and looks at the DC voltage, the actual stuff that's important.
Check out this one: http://www.sparkbright.co.uk/sparkbright-eclipse-battery-voltage-monitor.php There's a video on the site so you can see one in action.

It's the one that's worked perfectly in my bike for years. In bright sun when it's green it's hard to see but no matter, no light means all is well. When amber or red it's visible in all light conditions. It drew my attention immediately to a stator problem.

There are others available, I can just recommend the Sparkbrite as it's worked perfectly for me.
Click to expand...

Thanks, I think this is a good idea. Are the Sparkbrite units still available though?
 
After my last stator problem I installed a new 3 phase, insured proper clearance with the rotor and installed a Shindengen series regulator. The Podtronics I replaced had a small parasitic draw so I was pulling the main fuse when parking for a few days. The Shindengen has zero draw. Its only drawback it that it's huge so ended up on the downtubes. It would be nice to find a series regulator that would fit in the assimilator space.

Good luck! My knees aren't up to kicking anymore so I want the E-Start working well.


The SH847 is a series type rectifier. This type rectifier put a smaller load
on your stator and can run cooler. When there is no requirement for charge
current, this rectifier opens the input from the stator, unloading the stator
 
JimNH said:
The SH847 is a series type rectifier. This type rectifier put a smaller load
on your stator and can run cooler. When there is no requirement for charge
current, this rectifier opens the input from the stator, unloading the stator
Click to expand...

They mean regulator circuit, rather than rectifier, I expect.
 
Super,
I would also look at ICM(improving classic motorcycles) unit. I have used one for quite some time plus it fits right into your headlight shell with no drilling.Good customer service also.
Mike
 
Hey all,

Found a few minutes this morning to tear into the charging system wiring. When my daughter and I replaced the wiring about 7 years ago we did a really nice job of making connections, using heat shrink, wrapping with nice black tape, and using zip-tied rubber in strategic places to keep things from rubbing. I guess I have been a bit reluctant to open some of that up. It all looked so nice from the outside, and I have had no time. I did continuity testing back to the nicely wrapped section coming from the podtronics RR, which was all fine, however, it was tough to go any further than that without unwrapping/cutting to have a look at a section containing the connections from the yellow RR wires to the rest of loom. Discovered that both yellow wires from the RR had clearly gotten very hot where they had been joined to short sections of original 50+ year old wires that I had used to bridge the gap from the yellow wires to the loom. Looks like I had used them because they were the correct colors :).

Here are a couple of photos taken after the outer wrapping was taken off, and then before and after the heat shrink was removed:

Intermittent charging mystery
Intermittent charging mystery


I expect this could account for my intermittent charging mystery of 2025. Now I need to get rustle up a little bit of decent wire and a few connectors. I'll report back when I have it put back together and have started the bike to see if she'll charge after this has been sorted.

I suspect that these originally got very hot when the short developed on the wire from the alternator to the warning light assimilator when it was rubbing against the gas tank during the Nova Scotia trip. After that those connections would have been somewhere between poor and non-existent and may well have continued to get hot.

J
 
She is charging :)! At idle with lights off between about 13.8 and 14 volts. At about 3000 RPM about 14.2 volts. With the lights on around 12.3-12.4 at idle, and over 12.6 at about 2000 rpm.
 

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