charging @ rpms

[Sandgroper57]

FWIW, I put a meter on mine this morning. 12.6v not running. Running, idle 12.9v, 2000rpm 13.4v, 3000 and above 14v
Hope that is of some help.
Mike

[mr72]

FWIW, I put a meter on mine this morning. 12.6v not running. Running, idle 12.9v, 2000rpm 13.4v, 3000 and above 14v
Hope that is of some help.
Mike

Thanks. Sounds like yours is healthy

[mr72]

Well, good news and bad news.

Good news: my battery is not only good, but it's incredible. That's because ... you guessed it! It has not been charging at all.

I tested it today. It was 12.6 volts when it was 56 degrees this morning and the bike started right up. It revved to 5500rpm due to being on choke and the voltage was ... 12.6 volts. Rev above 5500rpm? 12.6 volts. Steady, solid, 12.6 volts.

I investigated further and found the connector between the alternator and the reg/rect was MELTED. And the wiring coming from the alternator was melted together. So the alternator output was shorted. My guess is it was this way when the PO determined the original reg/rect was bad and replaced it. Then he probably figured the battery was bad because it would "not hold a charge" (taking Sledge's advice, I suppose... I see Sledge responded on the PO's thread on this same issue) and replaced it with the current nearly-new AGM battery which holds a charge great. Probably will start the bike 20 times and run 100+ miles with the lights on etc. before needing to be recharged.

Anyway, with any luck the alternator and reg/rect are not actually bad, just the wiring. There's lots of frayed wires, wires with insulation worn off, etc. So I'm going to spend tomorrow morning straightening out the wiring and then I can see whether the alternator or reg/rect are any good.

There's not a good emoticon up there to describe my frustration with the PO. But, c'est la vie. I'll fix it, just like I did everything else.

[sledge]

If you are lucky the problem is just poor/dirty connections on the plug.

If you are unlucky the problem is in the generator. Shorted turns breaking down between each other, unbalanced voltages on each leg, overheating etc.

Time and your next move will tell 

[mr72]

It's not dirty connections. The connector is melted and fused together. I'm going to have to cut it out and crimp new connectors on.

[sledge]

In that case the stator winding is faulty. Its delivering unbalanced voltages across each leg, probably braking down between turns when hot. The system is seeing high and unbalanced currents, the plugs are overheating and melting as a result and the reg/rect is running home to mummy.

Replace the stator.......and the problem will go away. I promise you

[mr72]

I'll test it but it seems likely that the insulation on the wires wore through and it may be an old fashioned short on the stator side of the connector. All of the heat seems to be on that side. But who knows until I test it.

[mr72]

Fwiw stator test checks out. Will replace the melted connector tomorrow and check the r/r.

[sledge]

Stator might test OK statically but what about dynamically?

Using a 6/9v multimeter to check phase resistances and insulation resistance with the stator at ambient temperature won't tell you much. The phase resistances are that low its unlikely you will detect shorts with a multimeter, for that you need a Ductor tester. As for IR, again it might be fine at 9vDC but whats it like with 90vAC going through it?

Before you can say its ok you need to know is how the stator is behaving when its hot, been operating for a couple of hours and subject to full load voltages and currents in each leg   

[mr72]

FYI, I chunked the length of wire with the 3-prong melted connector on one end and bullet connectors on the other, and just crimped bullet connectors directly to the R/R input cable. Simple as that, eliminates about a foot of what looks like 16ga wire.

Fired it up and it's ~14V at idle and ~14V across the rev range up to about 5K. It was early in the morning, I didn't test above 5K. But this confirms it will charge my AGM battery (13.6V when fully charged) so we're in good shape.

Sledge, while I would like to appreciate your input, I really don't. Because it's condescending 100% of the time, wrong at least 50% of the time, and nearly always useless in terms of a shade-tree mechanic's ability to act on it. I followed the factory manual procedure for checking out the charging system and it checks out 100%. If it's good enough for Suzuki dealer mechanics, it's good enough for my garage. Others reading this thread, make up your own mind.

Melted connectors between the regulator/rectifier and stator on motorcycles seem to be extremely common, even across brands. It's plainly obvious that localized heating of the connector caused this most likely due to corrosion from galvanic effect causing heat in the connector. Eventually this heat dissipates down the wires and melted the insulation a few mm from the connector on the stator side, causing the stator to short between two of the three wires and produce insufficient AC voltage for the charging system to work.

Anyway to answer my own original question, at least on my bike, when it is working correctly, it will charge at idle, and across the rev range. There seems to be no need to hold high revs (>4K as previously suggested) to get it to charge. 

[sledge]

Well if you want to believe that ALL stator faults can be identified with a 9v multimeter and attempt to convince others that you are right, and you are prepared to accept yours is 100% serviceable despite some very strong indicators to the contrary......I will accept that   

[ShowBizWolf]

Just stumbled across this and wanted to add it to this thread for search purposes:

http://gstwins.com/gsboard/index.php?topic=38480.msg431967#msg431967

[mr72]

Just stumbled across this and wanted to add it to this thread for search purposes:

http://gstwins.com/gsboard/index.php?topic=38480.msg431967#msg431967

Thanks for that. It mirrors the factory service manual procedure and is precisely what I did.

BTW in my case the regulator rectifier plug with the two yellow wires was melted together with the plug from the alternator on the other side and the alternator wires had melted insulation right where they come out of the plug. I just cut off both sides and put bullet connectors on the regulator rectifier side to connect directly to the stator wires pictured in the first test, eliminating the pigtail. 150 miles, so far so good.

[user11235813]

@mr72,

Easy tiger, don't take offence, take a gate ;¬)

[SirHansford]

This info is probably no longer relevant to this thread, but I thought i'd toss it out anyways for anyone that can use it.  I spoke to a Suk dealership mechanic and he said that it will indeed charge at idle depending on the shape of the battery and it's not putting much back in the battery at idle,  but the optimal charging takes place around 2.5-3k,  supporting the link that Jack made.  Cheers all

[mr72]

I spoke to a Suk dealership mechanic and he said that it will indeed charge at idle depending on the shape of the battery and it's not putting much back in the battery at idle,  but the optimal charging takes place around 2.5-3k,  supporting the link that Jack made.  Cheers all

I think it also depends on the battery type. AGM batteries were not installed from the factory in 1989 so the old charging system may not produce enough voltage to charge one that is not almost dead at idle.

The manual says iirc 13.5-14.5 volts at 5k rpm and my fully charged AGM battery is 13.6 volts so if you have a battery like this and your charging system us at the very low end then it won't fully charge your battery and likely won't charge it at all at idle. But an old fashioned wet cell probably will charge just fine.