Burned alternator leads revisited

[sphen]

I’ve read on here that this is a common issue with wings. When I rebuilt this bike I went ahead and used individual spade terminals for each of the three leads. Smelled electrical smoke today and found this.

91CF6D28-9668-4085-810F-0541C1E7774B.jpeg (248.47 KiB) Viewed 872 times

So what exactly is the cause? Is something pulling too much ?

What is the fix? Better to hard solder the leads in?

[Lucien Harpress]

Normally it's dirty contacts that causes something like this. As I understand it you're getting raw juice from the stator before it hits the regulator and all that, so the electrical load is substantial. Any iffy contacts can up this load to a point where the connector melts. Guys solder it in to eliminate this potential failure point, and realistically this connector only gets unplugged if you want to remove the motor. Electrical gurus, please correct me if I'm wrong.

The fact this happened with new terminals is a bit concerning, though.

[sphen]

Any chance the stator is damaged? (It’s new)

[pidjones]

Any chance the stator is damaged? (It’s new)

You won't know until it's tested. Ohm it out, ohm it to ground. Was it charging when it happened? They are fairly robust. I have had good luck replacing the connector with RC helicopter high amperage connectors covered in shrink wrap.

[sphen]

What gauge wire do you recommend?

[sphen]

So the stator has 14g leads; the stock harness going to the recto has 16g (seems a bit small).

I have some 10g yellow (has to be yellow, right!?!) wire, so i cut and soldered in three patches.

The damage seems to have been localized around the terminals, so we’ll chalk this one up to corrosion or etc.

I test rode then felt the wires for heat - none.

I’m calling it done, but still monitoring…

[pidjones]

I mounted a digital voltmeter on my '79 and '78 after the '79's regulator drove system voltage to over 17 volts and fried my TFI modules. I can keep an eye on that now.

[Fred Camper]

One issue is heat, when the three terminals are tied together, the one in the middle often gets the hottest due to the heat of the other two junctions. This is why many eliminate the connector all together and solder them, as that prevents the slight voltage drop (and heat generation) common in a high current connector.

[Rednaxs60]

The OEM connector has been removed, replaced with connectors not really rated for the stator output current. Dirt and overamping appears to be the issue. You can solder the wires; however, I'd recommend a trip to a marine chandlery and get a waterproof high amperage connector to replace what is there.

[Sidecar Bob]

I've posted this before but here it is again:
When the terminals in a connector are new the internal resistance will be close enough to zero to make no difference but over time exposure to the air will cause the terminals inside any connector to oxidize. Eventually the oxidation will work its way between the contact points and the resistance can increase to a measurable level. When that happens 2 electrical principles come into play:
1) The voltage divider principle, which states that when there are multiple loads in series the voltage across each of them is in proportion to their individual resistances.
Examples (values selected to make the maths easy):
- if you have two 5 ohm resistances in series across a 10V supply, each of the resistors will "drop" 5V
- if you have a 30 ohm resistor in series with a 70 ohm resistor across a 20V supply the 30 ohm will drop 6V and the 70 ohm will drop 14V
2) Ohm's law for power states that Power = voltage multiplied by current (usually expressed P=E X I and measured in watts) and any power developed in a resistance has to be dissipated as heat (more power = more heat)

When the resistance is close to zero not much voltage will drop across it but as the resistance in the contact points increases the voltage across them will increase and as the voltage increases the power will also increase, causing the terminals to heat up, which will accelerate the rate of oxidization, causing the resistance to increase which increases the voltage, power, heat and so on until they become hot enough to melt the plastic.

So what causes the oxidization? Exposure to the elements (= rain water and dirt finding their way in) can play a role but mostly it is just exposure to the air for a few decades.

And how can we prevent it? The manuals never mention it but the terminals inside all of those connectors used on your bike really should receive periodic maintenance. The easiest thing to do is to simply unplug the connector and plug it back in again every 4 or 5 years so that any oxidation between the contact points is pushed out of the way but if you spray a bit of contact cleaner in after unplugging and unplug & re-plug it several times more of the oxidation will be removed and you can increase the interval to 7 or 8 years. If you really want to do it right, a tiny amount of dielectric grease or equivalent (whatever you use must be non-conductive) applied to the contact points before re-plugging can help prevent new oxidation from happening, increasing the interval to over 10 years, depending on the conditions the machine is used in and where on the bike the connector is.

The connector can also overheat if the terminals are loose and not contacting each other solidly. This can be fixed by gently squeezing the female terminals to tighten their grip.

Re wire gauge, we are all used to the wire sizes required by the Electrical Code for house wiring, which are generally several gauges larger than wiring in vehicles that has to carry similar current. What isn't obvious is that it is the wire's resistance and how much voltage that causes to be dropped that is important and many circuits in house wiring have 50' or longer runs (= 100' of wire out and back) so a larger wire is required to keep the resistance low. This chart is a good reference for which gauge is needed depending on length and current.

WireGauges.png (284.97 KiB) Viewed 700 times

[pjlogue]

When replacing terminals on these old bikes it's important to be sure the wires are cut back enough to have bright, clean wire exposed so your crimp/solder connections don't become a resistance point. I had this problem on my '76 GL1000 when I restored it. Unfortunately these wires coming from the alternator are short so cutting them back far enough to get to good clean copper but having enough length can be a problem. What I ended up doing was cutting enough wire back to get to good clean copper then splicing in a length of heavier Ga. wire using lap joint soldering and finally covering the solder joint with good quality heat shrink tubing that had the heat activated internal glue so it would not get any water inside.

-P.

[fcmusician]

I have a 83 Interstate. Checked my connections and they are clean with no sign of overheat or corrosion. This bike never had a ton of aftermarket lights, CB or radio installed. Just wondering if the people with problems have that heavy load on the charging system?

[pidjones]

I have a 83 Interstate. Checked my connections and they are clean with no sign of overheat or corrosion. This bike never had a ton of aftermarket lights, CB or radio installed. Just wondering if the people with problems have that heavy load on the charging system?

The system has a permanent magnet alternator - produces power no mater (given enough RPM) and dumps the extra to ground. High load just pulls voltage down.

[fcmusician]

I have a 83 Interstate. Checked my connections and they are clean with no sign of overheat or corrosion. This bike never had a ton of aftermarket lights, CB or radio installed. Just wondering if the people with problems have that heavy load on the charging system?

The system has a permanent magnet alternator - produces power no mater (given enough RPM) and dumps the extra to ground. High load just pulls voltage down.

Ahh ok. Just wondering. Had three Goldwings since 2000. None showed any problems like that. I did put some dilectric (SP) grease in there.

[pidjones]

I have a 83 Interstate. Checked my connections and they are clean with no sign of overheat or corrosion. This bike never had a ton of aftermarket lights, CB or radio installed. Just wondering if the people with problems have that heavy load on the charging system?

The system has a permanent magnet alternator - produces power no mater (given enough RPM) and dumps the extra to ground. High load just pulls voltage down.

Ahh ok. Just wondering. Had three Goldwings since 2000. None showed any problems like that. I did put some dilectric (SP) grease in there.

I suspect that you will be fine. Lack of regular maintenance and the corrosive atmosphere (near the battry vent, which is why I prefer AGM), plus high constant load over sub-par connectors seems to be the main issue. Eliminating just one of those three should go a long way to avoiding issues.