How to troubleshoot dead battery?
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Member
Joined: Apr 2008
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From: Wisconsin
How to troubleshoot dead battery?
First I thought it was the cold, second time, maybe I left something on, third time, now I'm pissed. How can I troubleshoot this to see what is draining the battery? Or possibly not charging it? Is there a way to test the alternater without removing it? Any other ideas? 2000 F-150 with a fairly new battery.
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Joined: Jun 2002
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From: Under the flightpath of old ORD 22R
Q1 :When the battery was dead did you jump start it and go or did you put the battery on a charger for n hours ?
Q2: How much time passed between the dead battery events ?
The only sure way to test the alternator is to pull it and have it tested.
- If Q2 is died 3 times in a row :
Did you check the alternator field fuse & the field connection at the alternator ?
Thread on the topic, what the MY in the thread, there are 2 M ranges in there.
https://www.f150online.com/forums/el...nator-why.html
Quick go / no go battery test, if you can disconnect the batteries and have a meter and charge you can do a quick test at home.
have the battery stand alone ( at the very least have it disconnected from the truck's system ).
Charge the battery on a 2A setting until fully charged. Once charged, take a voltage reading and record it. This should be in the 13.n range, on the low side, 12.9 / 12.8. 12.6 could be acceptable a battery that is getting to its last legs.
Let the battery sit for 3 to 4 hours, take another reading, should be within 0.2 / 0.3 VDC of the 1st reading.
Let the battery sit overnight and take another reading, should be what the 2nd reading was +/- 0.10 / 0.20 VDC of the 2nd reading.
This should put the overnight ( unhooked ) reading within ~0.4 VDC of the fully charged reading. If the battery is 1.0 VDC off the 1st reading, the battery is not holding a charge on its own, and should be replaced.
The alternator is not made to charge a low battery ( 12.5 or less ) on a continual basis, and can put too much strain on the alternator.
Q2: How much time passed between the dead battery events ?
The only sure way to test the alternator is to pull it and have it tested.
- If Q2 is died 3 times in a row :
Did you check the alternator field fuse & the field connection at the alternator ?
Thread on the topic, what the MY in the thread, there are 2 M ranges in there.
https://www.f150online.com/forums/el...nator-why.html
Quick go / no go battery test, if you can disconnect the batteries and have a meter and charge you can do a quick test at home.
have the battery stand alone ( at the very least have it disconnected from the truck's system ).
Charge the battery on a 2A setting until fully charged. Once charged, take a voltage reading and record it. This should be in the 13.n range, on the low side, 12.9 / 12.8. 12.6 could be acceptable a battery that is getting to its last legs.
Let the battery sit for 3 to 4 hours, take another reading, should be within 0.2 / 0.3 VDC of the 1st reading.
Let the battery sit overnight and take another reading, should be what the 2nd reading was +/- 0.10 / 0.20 VDC of the 2nd reading.
This should put the overnight ( unhooked ) reading within ~0.4 VDC of the fully charged reading. If the battery is 1.0 VDC off the 1st reading, the battery is not holding a charge on its own, and should be replaced.
The alternator is not made to charge a low battery ( 12.5 or less ) on a continual basis, and can put too much strain on the alternator.
Thread Starter
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Member
Joined: Apr 2008
Posts: 64
Likes: 1
From: Wisconsin
I had the battery and alternater checked at autozone and they wer OK. I crawled underneath to check the starter and the positive post had corosion and the wire actually came apart at the connection as I moved it. I replaced the connection tab, and hoped that my problems were gone. I now have a new electrical issue that I am starting a new topic on. (hope it isn't against site policy)
