3 replies [Last post]
cougsfan
cougsfan's picture
 Offline
Joined: 04/08/2007
Posts: 12

My '78 R80/7 has had the battery going dead as it sets for a few days. The battery is 2 years old, so it is a little young to go south. I bought a new battery and was getting ready to put it in and as I disconnected the negative lead on the old battery I decided to hook up a multimeter to see if there was current leaking. I am not overly adept at electrical stuff nor an expert on multimeters, but the meter I have is quality unit. I set it on the 200ma setting and hooked one to the disconnected ground wire and the other to the negative terminal. It read 10. I assume that means 10 milliamps is flowing. Is that enough to be a problem? If it is, how do I begin going about troubleshooting it?

Tonight I, after i am done charging the new battery, I will charge the old battery and see if it holds a charge disconnected. If it does, that will also tell me I have a substantial leak.

schrader7032
schrader7032's picture
 Offline
VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6327
Sounds like 10ma is a lot.

Sounds like 10ma is a lot. To find out where it might be coming from, you can begin to disconnect various circuits. Try getting to the fuses in the headlight shell. Pull each and remeasure the leakage. If they show which circuit it is, then look at the wiring diagram to drill down deeper to the exact component.

__________________

Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

cougsfan
cougsfan's picture
 Offline
Joined: 04/08/2007
Posts: 12
Do you get points taken away for being a bonehead?

I went out to start checking things and started looking closer at the Multimeter. The way it is set up, button position for 0-200 MA is the same as it is for 0-20 DC volts. To measure each, you change where you plug the leads in. I had the leads plugged into the Volts slot. So I was reading the 10 volts of my dead battery Applause (It has been setting for over a month, so she was as dead as a door nail). So I put the new battery in and checked for amperage leaks (with the multimeter set up right), and found none. My old battery just had gone bad.
At least I figured it out before I tore the headlight all apart looking for nothing!

schrader7032
schrader7032's picture
 Offline
VBMWMO #7032
San Antonio, TX
Joined: 10/27/2006
Posts: 6327
Good find! It pays to check

Good find! It pays to check the basics before things get out of hand.

__________________

Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.