Electrical Question
Thread Starter
|
Senior User
Joined: Aug 2012
Posts: 113
Likes: 0
From: Phoenix
Electrical Question
Any thoughts on why there seems to be a heavy draw on my battery (according to the gauge) that slowly goes down as the truck runs for a bit. It never goes into the plus side as if battery may be recharging. I tested the alternator by pulling the negative off while it was running and it did not die which is a good sign. Any thoughts?
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 783
From: Simi Valley, CA
Discharging battery: Did you install the battery in backwards? 1956 thru today: FoMoCo vehicles are 12V negative ground.
Did you buy a new battery recently? The batteries used in GM/ChryCo vehicles have the terminals reversed.
Some people don't pay attention to the location of their trucks battery terminals, buy one of these batteries.
Then they hook the cables up backwards: Positive cable to the negative (-) terminal. Negative cable to the positive (+) terminal.
Did you buy a new battery recently? The batteries used in GM/ChryCo vehicles have the terminals reversed.
Some people don't pay attention to the location of their trucks battery terminals, buy one of these batteries.
Then they hook the cables up backwards: Positive cable to the negative (-) terminal. Negative cable to the positive (+) terminal.
Logistics Pro
Joined: Mar 2005
Posts: 3,771
Likes: 80
From: tujunga, calif
Any thoughts on why there seems to be a heavy draw on my battery (according to the gauge) that slowly goes down as the truck runs for a bit. It never goes into the plus side as if battery may be recharging. I tested the alternator by pulling the negative off while it was running and it did not die which is a good sign. Any thoughts?
Thread Starter
|
Senior User
Joined: Aug 2012
Posts: 113
Likes: 0
From: Phoenix
There is an alternator in the truck. Like I mentioned, I had disconnected the battery while it was running and the truck kept running so I am not too suspicious of the alternator. It's weird. The battery does not run down fast either. I just put in a new one so we will see how it holds up
Logistics Pro
Joined: Mar 2005
Posts: 3,771
Likes: 80
From: tujunga, calif
There is an alternator in the truck. Like I mentioned, I had disconnected the battery while it was running and the truck kept running so I am not too suspicious of the alternator. It's weird. The battery does not run down fast either. I just put in a new one so we will see how it holds up
Thread Starter
|
Senior User
Joined: Aug 2012
Posts: 113
Likes: 0
From: Phoenix
Actually this is happening with the new battery. I was just wondering if I should be concerned with such a big load when I start it up. Maybe there is no real problem
Trending Topics
Laughing Gas
Joined: Dec 2010
Posts: 1,091
Likes: 14
From: Tucson, Arizona
Have you tried replacing your voltage regulator? Sounds like a possible problem candidate to me. Good luck!
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!
Joe Kucinski
Every 2026 Ford Truck Engine RANKED from WORST to FIRST!
Michael S. Palmer
The Best F-150 Deal of Every Trim Level (XL through Raptor)
Joe Kucinski
Logistics Pro
Joined: Mar 2005
Posts: 3,771
Likes: 80
From: tujunga, calif
After you start it the needle should go to the + side of the gauge and then return slowly toward the center as the battery charges back up.
Thread Starter
|
Senior User
Joined: Aug 2012
Posts: 113
Likes: 0
From: Phoenix
That's what I thought. It starts around -26 to -30 and then slowly hovers around zero maybe a little in the negative but I don't think it has ever been in the positive. Ill watch it. Like I said before it runs with the battery negative cable disconnected. Maybe it is the voltage regulator.
Logistics Pro
Joined: Mar 2005
Posts: 3,771
Likes: 80
From: tujunga, calif
That's what I thought. It starts around -26 to -30 and then slowly hovers around zero maybe a little in the negative but I don't think it has ever been in the positive. Ill watch it. Like I said before it runs with the battery negative cable disconnected. Maybe it is the voltage regulator.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 783
From: Simi Valley, CA
If the amp gauge needle shows a discharge, it won't be too long before the battery will be as dead as Julius Caesar.
Amp gauge needles hardly move if working properly. Engine off, headlamps on, wait 5 minutes. Then start engine, gauge needle should move to the charge side.
btw: When you installed alternator, did you replace generator ammeter gauge with one for an alternator? They're different as are the voltage regulators.
Amp gauge needles hardly move if working properly. Engine off, headlamps on, wait 5 minutes. Then start engine, gauge needle should move to the charge side.
btw: When you installed alternator, did you replace generator ammeter gauge with one for an alternator? They're different as are the voltage regulators.
Thread Starter
|
Senior User
Joined: Aug 2012
Posts: 113
Likes: 0
From: Phoenix
I apologize for my greenness, and I appreciate all of your help and insight. To be honest, it was installed before I bought it. I don't think there is any sort of regulator installed and am unsure of any gauge change out.
Logistics Pro
Joined: Mar 2005
Posts: 3,771
Likes: 80
From: tujunga, calif
When someone else has done the changes it's hard telling what they did. I'm not sure how they would have wired the alternator to the original gauge.
If the battery is fully charged you should get at least 12V. If you check it running it may be as high as 14.
If the battery is fully charged you should get at least 12V. If you check it running it may be as high as 14.