How to find a battery drain

csport

I have a 97 club car with a honda clone motor-

My problem is, when ever I leave the cart more than a couple hours, with the key off and the battery cable still on, the battery goes dead-

I have installed a harbor freight quick disconnect switch and when I do the disconnect, the battery will sit there for 3 plus weeks.

How can I find the draining source?

thank you

BGW

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

bswisher

What kind of electronics do you have on the cart? Radio, amp, lights etc?

csport

headlights with a switch and nothing else

mrgolf

Take negative battery cable loose. Then brush cable across post if you see sparks something is pulling power from battery. If so unhook one thing at a time that uses electric on the cart until you don't get sparks. You will know when you find what it is. (Brush battery cable each time you unhook something)

mrlmd

To measure a current draw, disconnect the negative battery cable (ground wire) and connect an ammeter between the negative battery post and the ground wire, then read the current you are drawing. If everything is off, you should have none, but if you have a reading, what you are reading is your battery drain, and to find the source you may have to pull fuses or disconnect things one at a time to see where the drain originates.

zombiehunter

Obvious question:
How old is the battery? Has it been tested?

mrlmd

He said if he disconnects the battery for 3 weeks, it is still good, but if it stays connected it dies. That is not a bad battery, that is a steady current draw which is what he has to track down, and to do that he has to follow my recommendation and measure the current across the negative battery post and ground, then disconnect things one at a time until he finds the source.

mrlmd

If you don't have a meter you can rig up a test light like in this post ---
Measuring electrical system leakage current



To test the electrical system for unwanted loads draining power, shut everything in the car off. Do just like you would do things when parking the car overnight. make sure all the lights and accessories are off.

Remove the negative post wire and check current draw with all electrical loads off using a test light. (I made a test light from an old tail lamp bulb.)

The dull glow in the light filament indicates a current drain problem. At this point I do not want to connect a current meter to check leakage because the short could damage the test meter! If a small clear test lamp like this does not light, then it is generally safe to directly measure current drain with a test meter.

Measuring Parasitic Current Drain

With all electrical loads off connect the meter, on a low amperes scale of about 1 ampere or so, in series with the battery negative post to ground. The positive meter lead connects to the car chassis, and negative meter lead to the negative post of the battery.

A good electrical system battery drain

This is measured on the 20mA scale. The mA scale reads in thousandths of an ampere. My 1989 Mustang LX, after I changed a bad alternator diode, now has about 1.73 mA of battery drain. This drain is all from the EEC-IV computer memory. Different radios and different computers might have different standby drains, as might accessories like clocks, but in no case should "overnight off" leakage exceed 25 mA or so. 100 mA is like leaving a small interior dome light on!

My Kenwood stereo draws 1.5 mA when connected. If you have a digital clock that stays on, an alarm, or some other load this current will be higher. At 75 mA, leakage could compromise battery life of infrequently driven vehicles. mA is milliamperes, or one 1000th's of an ampere.



The meter above is on the 20 mA scale, and is reading 1.73 mA. That is nothing. The battery charge would probably last for months of sitting.

Bad battery parasitic Drain

If the test light lit, you will want to locate the wire loading the battery. First make sure all lights are off. You can do this by having someone open and shut things with lights, like the trunk, and watching for a define large load change. You should see a definite load change when shutting doors with lights, like the glove compartment.

Connect the test light in series with the negative post, and start pulling feed wires. The first to check is the heavy charging wire from the alternator. A bad or leaky diode in an alternator is a very common source of overnight battery drain.

Connect wires one at a time to see what lead is drawing current. In my case it was the alternator lead! Even though the alternator was charging fine, it was also draining the battery. My problem was a bad alternator diode. There could be a variety of other problems, like a bad voltage regulator or a stuck relay contact.

Attached Images

	batt-fault-wires-drain.jpg (136.7 KB, 0 views)
	all-conn-drain.jpg (117.2 KB, 0 views)
	measleakcurrent.jpg (117.9 KB, 0 views)
	goodleakcurrent.jpg (136.0 KB, 0 views)
	MaMeter.jpg (103.2 KB, 0 views)

kantuckian

Good INfo Thanks