Topic: Another electrical issue! AAARRRGGGGHHHH!!!

[motorcycleclaude75]

Hey All,

Well yesterday, I thougth I had all my issues sorted out so i could go for a ride.  For some reason, I thought I would check how the bike was charging since I had issues before.

So I took my multimeter and tested the voltage from the battery when the bike was running.  The battery was fully charged before I started but what happend next baffled me. 

At first everything looked normal, but here is where it's weird.  I noticed the voltage jumping around, it would go from 12V, 11, 10, 14, 16, 10, 18, 12,11 etc...

And yes, I did say 16,18, it actually flashed briefly on the meter.  And then sometimes it would stabilize and work normal again but then do the same weird thing minutes later.  This happened several times so it's not my imagination.

What am I up against, can someone pinpoint what i should look at first?   

[KB02]

While I am not an electrical wizard, I would say that it sounds like either a bad regulator or simply a loose connection somewhere that keep making and loosing contact.

That would be what I would look for, anyway.

-Bob

[eurban]

Could be the bike but sounds like your meter.

[brimar6]

I'll second wh at KB02 said; " I would say that it sounds like either a bad regulator or simply a loose connection somewhere that keep making and loosing contact." To start with clean all your electrical connections even if they look clean, especially the grounds. A small wire tooth brush or very fine sand paper will do. I would'nt worry to much about your meter, it's probably a lot more reliable the your bikes electrical system.

[motorcycleclaude75]

Hey All,

We'll I checked my regulator, seems fine.  I then cleaned all connections,applied some dielectric grease.

Checked my voltage, performed the charging test and seemed to work fine.

I recorded the voltage of the battery without the bike running before going for a ride.  The bike ran really well and I then checked the voltage when I got back.  The voltage was higher than before my ride so it looks like it's charging fine.

So now I'm going for a real ride and I'm not going to worry about charging. 

Thanks all.

[Bodi]

Sounds good.
The best general check for over-charging is to look at the battery fluid level. Overcharging will cause the level to drop fairly quickly.
A hygrometer is the only way to really tell charge level, you can get a small one with a floating ball system at most bike shops for a couple of dollars. With 5 balls, 4 floating is fully charged, less is undercharged, all 5 floating is overcharged.
If it's overcharging I would suspect that the regulator is not getting full battery voltage.
There's a small voltage drop on any wire, switch, fuse, or connector carrying electrical current - this is unavoidable. When the connections and switch contacts get dirty and corroded, the voltage drop increases. Frayed and partly broken wire causes this too, undamaged wire even when very old is not a problem. The regulator is at the end of a long series of wires, fuses, and switches. If you measure the voltage at the regulator "bat" terminal - black wire - it should be within a volt or so of the actual battery "+" voltage. This is the voltage the regulator is trying to hold at about 14VDC. If there's a 2 or 3 volt drop from the battery to the regulator, then the system is regulating 14V but making 16-17V at the battery and overcharging it.
Installing an automotive relay at the regulator (providing power from battery "+" directly when the ignition is on) eliminates this problem although all fuseholders, connectors and switches should be clean for proper operation of the ignition and lights anyway.

[oldbiker]

I would also point out that a digital voltmeter is not the best for reading battery voltage on a running bike because it responds instantly to any spikes in the system. An analog meter has inherent damping due to physical inertia which gives a much better reading in this situation. if you are lucky enough to have both, connect them both at the same time and you will see the analog meter give a steady reading while the digital meter jumps all over the place. Digital meters are more specialised and more suited to measuring in electronic and computing circuits.