Notices

Battery overcharging?

Thread Tools
 
Search this Thread
 
Old Mar 15, 2013 | 11:17 AM
  #1  
jon705's Avatar
jon705
Thread Starter
|
Freshman User
Joined: Dec 2012
Posts: 34
Likes: 0
Battery overcharging?

The battery light is on in my dash. To test it I probed the car battery with a multimeter. Car off the battery reads 12.5 volts. With the car running and no headlights on, heater fan off, etc the meter reads 15-15.5volts. When I turn everything electrical I can think of on the meter reads 14-14.5volts. Is this normal or is the second scenario overcharging the battery? What else can I test that may be keeping the battery light on in the dash?
 
Reply
Old Mar 15, 2013 | 11:28 AM
  #2  
Franklin2's Avatar
Franklin2
Moderator
25 Year Member
Photogenic
Community Builder
Community Influencer
Joined: Jan 2001
Posts: 56,977
Likes: 2,733
From: Virginia
Club FTE Gold Member
What year, model, truck are you working on?
 
Reply
Old Mar 15, 2013 | 12:12 PM
  #3  
jon705's Avatar
jon705
Thread Starter
|
Freshman User
Joined: Dec 2012
Posts: 34
Likes: 0
98 lincoln navigator
 
Reply
Old Mar 15, 2013 | 12:34 PM
  #4  
BPofMD's Avatar
BPofMD
FTE Legend
Veteran: Navy
15 Year Member
Liked
Community Favorite
Joined: Jul 2005
Posts: 65,938
Likes: 1,432
From: Millersville, MD
Club FTE Silver Member

Bad alternator probably.
 
Reply
Old Mar 19, 2013 | 11:50 AM
  #5  
jon705's Avatar
jon705
Thread Starter
|
Freshman User
Joined: Dec 2012
Posts: 34
Likes: 0
The 15.5v reading that I was first getting while idling with no accessories on must have been a fluke. Read the meter yesterday with her in idle, no accessories and it hit 14.5v. Accessories on she hit 14.5v. Driving down the road about a mile the dash light went off. Not sure what tripped it in the first place but there doesn't seem to be an issue.
 
Reply
Old Mar 28, 2013 | 11:01 PM
  #6  
Rusty_S's Avatar
Rusty_S
Lead Driver
15 Year Member
Photogenic
Photoriffic
Liked
Joined: Apr 2007
Posts: 5,958
Likes: 105
From: Houston
I had a voltage regulator go bad and two things I experianced. One was my battery kept going dead over night for no reason. My amp gauge was reading 45 Amps when running (70 amp alternator) and when I checked the battery with the key off the battery had 15.5 volts. With car running the alternator was putting out 15 volts. Truth is an alternator is supposed to put out slightly higher voltage than battery voltage but vary amperage to charge the battery and keep your system going. Battery voltage is 12.7 for a new battery or a fully charged battery. Every charging system Ive seen working properly runs at 14 volts with engine running. Some vehicles might be different but all the ones ive seen never went over 14 volts when working properly.

I know your problem is resolved now but if your battery starts going dead over night and you have nothing on to cause it then I would check your regulator if you have an external regulator otherwise time to get a new alternator.
 
Reply
Old Apr 14, 2013 | 10:21 AM
  #7  
srteach's Avatar
srteach
Elder User
Joined: Mar 2012
Posts: 609
Likes: 0
Originally Posted by jon705
The 15.5v reading that I was first getting while idling with no accessories on must have been a fluke. Read the meter yesterday with her in idle, no accessories and it hit 14.5v. Accessories on she hit 14.5v. Driving down the road about a mile the dash light went off. Not sure what tripped it in the first place but there doesn't seem to be an issue.
I know the problem is solved, but 15VDC may not be a fluke. The voltage regulator could be going bad and putting that much voltage out. If it is going bad, that 15VDC may not be the output at all times.

A good alt / volt regulator will put 14.2 to 14.5 out at all times, load or not. Just keep a check on it.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Tenvol1968
Modular V10 (6.8l)
1
Sep 5, 2014 10:45 AM
golfdude
1987 - 1996 F150 & Larger F-Series Trucks
11
Oct 25, 2008 11:15 PM
WiseMagic
1997 - 2006 Expedition & Navigator
2
Oct 15, 2007 02:49 PM
freerider54911
Explorer, Sport Trac, Mountaineer & Aviator
4
Feb 13, 2005 09:11 PM
MrSandman
1997 - 2006 Expedition & Navigator
13
Dec 28, 2003 09:08 AM




All times are GMT -5. The time now is 03:59 AM.

story-0
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-1
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-2
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-3
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE
story-4
10 Best Ford Truck Engines We Miss the Most!

Slideshow: The 10 best Ford truck engines we miss the most.

By Joe Kucinski | 2026-05-12 13:09:47


VIEW MORE
story-5
2026 Shelby F-150 Off-Road: Better Than a Raptor R?

Slideshow: first look at the 810 hp 2026 Shelby F-150 Off-Road!

By Brett Foote | 2026-05-12 12:50:07


VIEW MORE
story-6
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

Slideshow: Everything You Need to Know about the 2027 Super Duty Carhartt Package!

By Michael S. Palmer | 2026-05-07 17:51:06


VIEW MORE
story-7
10 Most Surprising 2026 Ford Truck Features!

Slideshow: 10 most surprising Ford truck options/features in 2026.

By Joe Kucinski | 2026-05-05 11:17:22


VIEW MORE
story-8
Top 10 Ford Trucks Coming to Mecum Indy 2026

Slideshow: Here are the top 10 Fords coming to Mecum Indy 2026.

By Brett Foote | 2026-05-04 13:49:49


VIEW MORE
story-9
5 Best / 5 Worst Ford Truck Wheels of All Time

Slideshow: The 5 best and 5 worst Ford truck wheels of all time

By Joe Kucinski | 2026-04-29 16:49:01


VIEW MORE