bat die over night
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Joined: Nov 2008
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bat die over night
i have a 1999 f550 the battiers keep die over night i check for a drain found one took off the fuse but bat keeps die when i check for ground on the frame or the motor these is none.... does anybody have the wiring to show the grounds?
Lead Driver
Joined: May 2003
Posts: 9,303
Likes: 48
From: Lyndonville, Vermont
You have something staying on. Check glove box light or something like that. Hood light?
You don't have a ground issue! You have something staying on. If may not be easy to find. Alternators do this at times. Have it checked by an expert..if you can't find anything. Disconnect battery at night so you won't kill it. Every time you kill it 20% of the battery life is lost..
Dick
You don't have a ground issue! You have something staying on. If may not be easy to find. Alternators do this at times. Have it checked by an expert..if you can't find anything. Disconnect battery at night so you won't kill it. Every time you kill it 20% of the battery life is lost..
Dick
FTE Remembers
Joined: Jul 2005
Posts: 65,938
Likes: 1,432
From: Millersville, MD
I think he's saying he disconnected battery and it goes dead. I'd take the truck in to where he bought the battery and have THEM check it. May be a bad alternator. A bad battery will kill an alternator..... 99f, does it stay running if you remove the ground cable from battery while it is running?
Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
I know that's the common test, but disconnecting the battery while the engine is running can cause a substantial voltage spike. Which isn't good for the electronics.
I would start by charging the battery alone (disconnected from the truck). Then let it stabilize for a few hours (or overnight) then check it's voltage. A battery should hold 12.66v minimum, as there are 6 cells at 2.11v each. If the battery can't hold 12.6v then it needs to be replaced as it's internally discharging.
I would start by charging the battery alone (disconnected from the truck). Then let it stabilize for a few hours (or overnight) then check it's voltage. A battery should hold 12.66v minimum, as there are 6 cells at 2.11v each. If the battery can't hold 12.6v then it needs to be replaced as it's internally discharging.
Senior User
Joined: Feb 2008
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Another possibility is if the battery is hooked up,a diode made be bad in the alternator causing draw when shut off,the diode being a one way electrical check valve in the alternator.
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Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
That can be checked by DMM or test light. Disconnect the ground and put the test light or DMM in line between the ground terminal and the battery ground post. You should see about 20mA draw (normal) or more, then disconnect the charge wire from the alternator. If the light goes out or the draw drops off when you disconnect the charge wire, then the alt has a bad diode.
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