ES-450: Too much current thru orange wire

[Testarossa]

In restoring the T post-flood, I installed the Electrosport ES450 rectifier/regulator. All seemed good -- bike ran well.

Last week, on the way home from a run to Boulder, the battery went flat. The orange wire that senses battery voltage had blown its 10-amp fuse (I have the ignition switch wire feeding the fuse block).  The original wiring diagram shows the orange wire unfused so I connected it to the fuse box main buss, ganged with the feed from the ignition switch. As a switch I'm using a honking big push-pull automotive item.

The battery -- new this year -- takes and holds a charge. When I turned on the ignition switch the bike fired up properly but the orange wire, along with the feed from the ignition switch, immediately overheated and began to smoke at the terminals. Nothing else appears to overheat, including the connections to the stator.

How much current should that orange wire pull?  Certainly not more than 10 amps. Has the voltage regulator failed? A voltmeter shows 12.4v with the ignition off, then jumps around unreadably with the engine running. I've never seen a voltmeter do that.

Experts please advise.

[Wayne Orwig]

I would assume that switched power line passes power to activate the field. 10 amps would be marginal. I would fuse it, but a 15 or even a 20 amp fuse might be a better choice.

[Testarossa]

Maybe it should be fused. Electrosport's wiring diagram doesn't show it that way. Even so, should it draw enough current to melt the insulation?  I don't think so.

[rodekyll]

If you're smoking that wire I assume you have a dead short.  The wire is 'toast'.  Continue to use it as a problem isolation device -- start disconnecting things until it stops smoking when you hit the button.  Have a replacement wire handy to fix it once the problem is found, and have a fire extinguisher in the vicinity, just in case.

The prime suspect besides the uninsulated wire lying on the frame somewhere is the voltage regulator.  

[Testarossa]

Couldn't find a short so I'll assume the regulator is dead. Wrote to Electrosport for what to do next. In the meantime I'll reinstall the diode board and plastic regulator and see what's what.

[pressureangle]

A voltmeter shows 12.4v with the ignition off, then jumps around unreadably with the engine running. I've never seen a voltmeter do that.

Experts please advise.

Regulator has gone crazy, full output into a less-than-fully charged battery (or fully charged if voltage is high enough) is overamping the system.

[Testarossa]

I installed a new ESR450 and voltage at idle now looks normal at the voltmeter on the handlebar (wired from the ignition switch hot lead to ground). BUT two different VOMs show wild voltage (jumping around like crazy including readings over 100v) at the battery terminals, at idle. What would cause this?

Battery is new, with normal voltage with ignition off. Bouncing reading occur only once the engine starts.

Weirdness in the stator or rotor?

[Triple Jim]

I installed a new ESR450 and voltage at idle now looks normal at the voltmeter on the handlebar (wired from the ignition switch hot lead to ground). BUT two different VOMs show wild voltage (jumping around like crazy including readings over 100v) at the battery terminals, at idle. What would cause this?

It's entirely possible that it's RF interference to the meter from the ignition system, causing false readings.  If you have an analog meter, try that.  If the voltage were really fluctuating wildly, you'd be able to see obvious flickering of incandescent lights like the headlight.

[Kiwi_Roy]

I installed a new ESR450 and voltage at idle now looks normal at the voltmeter on the handlebar (wired from the ignition switch hot lead to ground). BUT two different VOMs show wild voltage (jumping around like crazy including readings over 100v) at the battery terminals, at idle. What would cause this?

Battery is new, with normal voltage with ignition off. Bouncing reading occur only once the engine starts.

Weirdness in the stator or rotor?

Dirty battery terminals, remove. scrape them clean then a coating of Vaseline. You are seeing the open circuit Voltage of the alternator because it's not clamped by the battery. Don't forget to check the main ground where it connects to the chassis.

The Orange wire should only have a few mA I think, possibly the field current

[Wayne Orwig]

Dirty battery terminals, remove. scrape them clean then a coating of Vaseline. You are seeing the open circuit Voltage of the alternator because it's not clamped by the battery.

 :+1

Bad battery connection somewhere.

[rodekyll]

I'm thinking it's a meter problem -- either a low battery or the thing is set to A/C instead of DC. 

[Testarossa]

Battery is new, with clean terminals -- all connections are new, including new battery cables and ground connex, because I rebuilt the entire electrical system after the flood. I'm inclined to think Triple Jim is right about RF interference since this has now happened with two rectifier/regulator units and two digital VOMs, but the dead-simple cigarette-lighter voltmeter reads steady and healthy.