Short Circuit Test

[lee82]

I am seeing numerous posts that batteries are being run down when the scooter is parked over night. A simple way to determine if current is being drawn from the battery makes use of a test light. This is a device that resembles a large pencil, it has a colored plastic handle with a small light bulb inside. A sharp probe extends from one end of the plastic and a 3 or 4 foot lead ending in a clip extends from the other end. If you touch the probe to one battery terminal and the clip to the other battery teminal the light will glow very bright.
To use this tool to test for a short circuit, disconnect the negative battery cable, touch the test light probe to the negative battery terminal and the clip to the disconnected cable. If any current is flowing due to a short, the light will glow. If the current draw is very small the light will be very dim, so you need to make sure that test bulb is viewed in a relative darken area.
These test lights are availble at any auto store.

[knorrtech]

Good Post - Will try it out - Thanks

[earlwb]

if the circuit tester light doesn't light up, there could still be some current draw when off.
On some of these alarm systems and such one might have to use a voltmeter and set it for current to measure a light current draw.

[lee82]

You are right Earl, a sensitive ammeter would give a more accurate reading of the current draw.
However, I was troubleshooting a short in a VW bug and didn't have an ammeter so I used the test light and I was amazed at the fact that I could see a dim glow on the filiment of the test light. I am pretty sure that the current flow must have been just a few milliamps.

[fulltimerart]

If you are getting a glow in the tester (or a reading on the meter) unplug the fuses 1 at a time till the lite goes out and that will be the circuit with the problem. Art

[twisterak47]

This is some good info. THANKS

[motomech]

The most common way to test for a drain is to place a voltmeter in series to one of the batt. leads(doesn't mater which one)and it's corresponding terminal. With the key off, the reading should be zero.
By far, the most common cause of a drain on an Asian two-wheeler will be a faulty rectifier(usually hermetically sealed-up with the regulator, hence, called the rectifier/regulator ASM). These usually produce readings in the 2 to 4 volt range(tri-phase rectification, each diode handling 4 volts). A total shunt, like pinched wires would blow a fuse. A device drain would be sm., if it's under 1/2 volt, it really isn't a concern. That's why a amp meter really isn't necessary. Besides, amp meters are virtually impossible to use to check charging and most mechanics don't keep them in their box(might be in shop tools though).
Motomech in Costa Rica