Whoa! 16V on the multimeter!

OK how much juice is too much?

I have a 1977 KZ650B1 model that has a new rectifier, regulator and battery. I hooked up some leads for an electric vest today and ran the bike to see if it could handle the load.

Yikes! I was running almost 16V according to my multimeter when I ran the bike up from idle speed to about 3500 rpm. I was getting a LOT of juice.

When I would let the bike idle I'd drop down to 12.2V or so (a little less with the vest going) but the voltage was zooming any time I gave it some gas.

Admittedly I was checking things out without the bike fully warmed up ... my KZ manual says between 14-15V is normal. So what might I be experiencing here?

Well, at least, the alternator can handle the power of the vest.

You need to do a voltage check on the regulator.

Using the battery's negative-post as ground, measure the voltage on the regulator's power wire. That should be the brown (or red) wire. The voltage there should match the battery's positive-terminal voltage while revving. If the voltage on the regulator is much lower than the battery, you have a bad positive connection somewhere.

Next check the voltage on the ground of the regulator. That's the black/yellow wire. It must be zero volts. If not, then you have a bad ground connection.

If the brown wire voltage matches the battery's voltage, and the ground is constant zero volts, the regulator is defective.

The most common place for a bad positive connection is in the fuse box itself. Look for burned wires. Next would be at the ignition switch. Then it could be anywhere else in the path from battery to regulator.

Post edited by: loudhvx, at: 2007/10/26 22:03

Excess of 14.5VDC will damage your battery. I must assume that your battery has been fine under the conditions you describe, therefore I suspect your meter is not reading the voltage accurately.

Check out this meter for calibration accuracy.

Emma wrote:

Excess of 14.5VDC will damage your battery. I must assume that your battery has been fine under the conditions you describe, therefore I suspect your meter is not reading the voltage accurately.

Check out this meter for calibration accuracy.

That's what I was thinking too, 16v is pretty high. Chinese meter? Well hopefully that is what it is!

RonKZ650 wrote:

Chinese meter? Well hopefully that is what it is!

Metric volts? :blink:

:laugh:

I doubt it's the meter.
His battery voltage goes even higher if he uses the lights... classic symptom of bad connection in fuse holder area.

In my experience charging at 16V DC will damage all lead acid batteries. If the bike has been in use and charging at 16V, the battery will be fried, it is only a question of time. This is my experience with a KY1000 and Honda Goldwing. The root cause in both of these cases was the regulator/rectifier which was integrated as a single device.

I still suspect the meter used to measure 16V is the problem.

Yes, it's a matter of time, but I don't think it's been very long. It's a new battery so I assume it doesn't have much time on it.

Loudhvx (Lou) is the electrical guru here (and in real life), I just play second fiddle

Check out Lou's WebSite

Post edited by: steell, at: 2007/10/28 23:10