Author Topic: .52 amp battery drain  (Read 2792 times)

Offline Restoredrustbucket

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.52 amp battery drain
« on: August 17, 2017, 12:51:37 AM »
Hey, so ive been having a .52 amp draw on my 1986 scottsdale, ive tried unplugging all the fuses and it still shows a .52 draw, I cleaned the grounds that connect to the battery, ive tried turning off the courtesy lights, which should happen when the fuse is our anyways, any ideas what could be causing the Draw? The battery is new and doesn't drain if unplugged.

Offline blazer74

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Re: .52 amp battery drain
« Reply #1 on: August 17, 2017, 02:59:50 AM »
Alternator diode. 
Memory accessories added?

Offline Restoredrustbucket

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Re: .52 amp battery drain
« Reply #2 on: August 17, 2017, 03:06:30 AM »
Thanks for the reply, I'll check the diodes tomorrow, by memory accessories do you mean like a clock? If so I do not have any

Offline blazer74

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Re: .52 amp battery drain
« Reply #3 on: August 17, 2017, 04:35:04 AM »
Any thing that draws power when ignition is off.
Alarm, radio, auto start.


Offline Restoredrustbucket

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Re: .52 amp battery drain
« Reply #4 on: August 17, 2017, 04:50:51 AM »
I actually don't know if it has an alarm or not, it doesn't have a clock and I've pulled the radio fuse and it had no change,  how can I tell if it has an alarm system installed?

Offline blazer74

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Re: .52 amp battery drain
« Reply #5 on: August 17, 2017, 02:10:07 PM »
Aftermarket would be tapped into the fuse panel or a extra power wire from a hot battery source.

Under hood light could cause a draw if installed.

Offline Restoredrustbucket

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Re: .52 amp battery drain
« Reply #6 on: August 17, 2017, 06:28:49 PM »
I did a diode test and the alternator reads 519 (I dont know what mesurment here's a picture) one way and 0 on the other way (switching wires)

Offline bd

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Re: .52 amp battery drain
« Reply #7 on: August 17, 2017, 06:59:56 PM »
Did you mean 0.519?  Diode tests generally indicate the forward voltage required to energize the PN junction - 0.52v is actually at the low margin of the acceptable range for a silicon diode.

To determine whether the alternator is the source of the draw, first unplug the regulator connector from the alternator to see if there is any change, then remove the charge lead from the B+ post of the alternator to see if there is a change.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Restoredrustbucket

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Re: .52 amp battery drain
« Reply #8 on: August 17, 2017, 11:34:40 PM »
I unplugged the alternator and the draw is gone. Do you think the alternator is bad or could it be the wire leading to it?

Offline bd

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Re: .52 amp battery drain
« Reply #9 on: August 18, 2017, 12:38:14 AM »
Is the wire you unplugged from the alternator chafed to ground?  If it is, then repair or replace the damaged wire and proceed to the next step.  If the wire you unplugged from the alternator is not chafed to ground, simply proceed directly to the next step.  With the ignition switched off and regulator connector unplugged from the alternator, use a test light to probe alternately the two wires in the regulator connector.  One wire should illuminate the test light, the other should not.  Cycle the ignition on then off and retest the regulator wires.  If the two wires consistently test as described, replace the alternator.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)