Chasing down a battery drainer...
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Posting Guru
Joined: Aug 2002
Posts: 1,493
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From: Great NW
Chasing down a battery drainer...
I have a '74 F100 that I recently put a new engine in. While I was at it, I also replaced the, Battery, the cables, the starter and solenoid ad nauseum...
But something in the truck is now causing the battery to drain it's charge over night. I put a meter on the (-) battery terminal and the (disconnected) -- cable and it showed it was draining about .18 Milliamp with everything turned off and all fuses removed.
Without having to go through the entire electrical system to find the culprit (which I may still have to do), any ideas on where I should check?
But something in the truck is now causing the battery to drain it's charge over night. I put a meter on the (-) battery terminal and the (disconnected) -- cable and it showed it was draining about .18 Milliamp with everything turned off and all fuses removed.
Without having to go through the entire electrical system to find the culprit (which I may still have to do), any ideas on where I should check?
Posting Guru
Joined: Aug 2000
Posts: 1,984
Likes: 2
Chasing down a battery drainer...
Check the mercury switch that turns the under-hood light on. Then check the sun visor courtesy lamps (if equipped). Make sure the hazard light switch is completely turned off.
It might also be an internal drain in the ignition switch itself. You could try jiggling it with the milliamp meter connected.
A drain like yours drove me crazy a while back on my daughter's Mustang. It turned out to be the visor courtesy light not turning off. With the visor in the upright position, no one could see the bulb staying lit.....
It might also be an internal drain in the ignition switch itself. You could try jiggling it with the milliamp meter connected.
A drain like yours drove me crazy a while back on my daughter's Mustang. It turned out to be the visor courtesy light not turning off. With the visor in the upright position, no one could see the bulb staying lit.....
Postmaster
Joined: Jan 2003
Posts: 4,417
Likes: 3
From: Durham, NC
Chasing down a battery drainer...
A drain of .18 milliamps (180 microamps) will not drain your battery overnight.......Try letting your battery set overnight
with the negative terminal disconected and see if it still goes
dead. If it does, your battery is bad...
with the negative terminal disconected and see if it still goes
dead. If it does, your battery is bad...
Post Fiend
Joined: Feb 2000
Posts: 5,130
Likes: 8
From: Brea CA
Chasing down a battery drainer...
You're right, I was assuming he meant 180mA but that's still not enough to drain a battery overnight. If a battery has an 80A/H rating it should be able to deliver 4 amps over 20 hours until it hits 10.5 Volts.
barry
barry
Post Fiend
Joined: Nov 2002
Posts: 9,987
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From: Memphis, TN
Chasing down a battery drainer...
This doesn't pertain directly to this thread, but it's good reading about batteries.
Freshman User
Joined: Mar 2003
Posts: 29
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Chasing down a battery drainer...
Try doing the battery drain checks with all the fuses Installed. Note the reading, Then remove 1 fuse at a time and note the reading. Re-install the fuse and then do the next fuse...and so on.
Note: take a look at the thread labelled "Battery Drain" from Mkrog. It should help you out..
Let us know how you make out & Good Luck
Deano
Note: take a look at the thread labelled "Battery Drain" from Mkrog. It should help you out..
Let us know how you make out & Good Luck
Deano
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Posting Guru
Joined: Jun 1999
Posts: 2,007
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From: Oregon
Chasing down a battery drainer...
The current drain sounds about right for memory power on the radio. Is it wired direct?
You didn't say if the battery was totally dead or just drained enough not to start.
I see you replaced about everything, but I don't see the alternator listed. Get the truck running, turn lights and heater fan on and check your voltage output.
If the charging system checks OK it might just be the ignition switch. I have a 76 F100 that I had to replace the switch on. They just get old and intermittant...
You didn't say if the battery was totally dead or just drained enough not to start.
I see you replaced about everything, but I don't see the alternator listed. Get the truck running, turn lights and heater fan on and check your voltage output.
If the charging system checks OK it might just be the ignition switch. I have a 76 F100 that I had to replace the switch on. They just get old and intermittant...
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Chasing down a battery drainer...
