battery's continue to die?
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Cross-Country
Joined: Mar 2010
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battery's continue to die?
I have a 2016 ford Super duty with the 6.7L diesel and I am having random problems with the batteries going dead. Once every couple of weeks they are dead as a door nail I hook them up to trickle charger and take two brand new batteries and they struggle to start the truck. The batteries tested fine and one of them shows 80% charge the other dead. I charge them both up and leave on the trickle charger and a couple months or so later same problem. What could be wrong I am loosing it vi ground somewhere right? I saw on YouTube where the battery junction box got a little moisture in it and they had to replace it. That was in a 2020 truck though. Thoughts? Help?
Logistics Pro
Joined: Jan 2010
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How often do you drive this truck? Daily? Once a week? Once every few months?
Generally speaking batteries should hold a charge over a couple months and still be able to start a vehicle that hasn't been run, unless the batteries are going bad. You say you're using new batteries, are these brand new from the store batteries or just batteries you have charged up sitting around?
What kind of CCA do you have on these batteries? I would be using nothing less than 750 CCA, more is always better (I try to find 950 CCA batteries).
If these are new batteries with adequate CCA, and you're driving this thing on a semi-regular basis, then you either have a parasitic draw (could be an aftermarket device that is left plugged in or a short in the electrical system), or your alternator is going bad and not adequately charging the batteries while driving.
Generally speaking batteries should hold a charge over a couple months and still be able to start a vehicle that hasn't been run, unless the batteries are going bad. You say you're using new batteries, are these brand new from the store batteries or just batteries you have charged up sitting around?
What kind of CCA do you have on these batteries? I would be using nothing less than 750 CCA, more is always better (I try to find 950 CCA batteries).
If these are new batteries with adequate CCA, and you're driving this thing on a semi-regular basis, then you either have a parasitic draw (could be an aftermarket device that is left plugged in or a short in the electrical system), or your alternator is going bad and not adequately charging the batteries while driving.
Thread Starter
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Cross-Country
Joined: Mar 2010
Posts: 88
Likes: 12
How often do you drive this truck? Daily? Once a week? Once every few months?
Generally speaking batteries should hold a charge over a couple months and still be able to start a vehicle that hasn't been run, unless the batteries are going bad. You say you're using new batteries, are these brand new from the store batteries or just batteries you have charged up sitting around?
What kind of CCA do you have on these batteries? I would be using nothing less than 750 CCA, more is always better (I try to find 950 CCA batteries).
If these are new batteries with adequate CCA, and you're driving this thing on a semi-regular basis, then you either have a parasitic draw (could be an aftermarket device that is left plugged in or a short in the electrical system), or your alternator is going bad and not adequately charging the batteries while driving.
Generally speaking batteries should hold a charge over a couple months and still be able to start a vehicle that hasn't been run, unless the batteries are going bad. You say you're using new batteries, are these brand new from the store batteries or just batteries you have charged up sitting around?
What kind of CCA do you have on these batteries? I would be using nothing less than 750 CCA, more is always better (I try to find 950 CCA batteries).
If these are new batteries with adequate CCA, and you're driving this thing on a semi-regular basis, then you either have a parasitic draw (could be an aftermarket device that is left plugged in or a short in the electrical system), or your alternator is going bad and not adequately charging the batteries while driving.
When all of this first happened it was used daily pulling a mower trailer around the first two times. the last couple times the truck has been used weekly to plow with. We use rotorcraft 850CCA Batteries. Never thought about the alternator having a problem the truck is a 2016 with around 36,000 miles on it.
Logistics Pro
Joined: Jan 2010
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It might only have 36k on the clock, but if you've been doing a lot of short trips and plowing, that alternator has likely seen the equivalent of 100k+ miles. You're also using that alternator to power the hydraulics on that plow, so that adds stress to it. I'd get it bench-tested.
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Cross-Country
Joined: Mar 2010
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Just checked the alternator Voltage at the battery without it running I am showing 12.2 Volts and with it running it shows I am getting 14.3 Volts that should be sufficient enough of a test for the alternator right? Or do you think I should remove it and have it tested., not at all saying its not a potential problem only thing is it doesn't fail except at random times. For example, with the plow going up, down, scoop, wing, and side side to side motions for hours on end plenty to drain the batteries with an inadequate alternator I would think/assume. I took it by the diesel shop when all this started and they basically said if its not acting up nothing that can do to figure it out, which I understand. However, we all know how expensive it is to "throw parts" at these things.
FTE Leadership Emeritus
Joined: Sep 2000
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From: Stephensville WI
14.3 volts while the engine is running tells me that the alternator is probably good. That is what you should see.
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Fleet Mechanic
Joined: Dec 2015
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From: Washington Coast
If you are reading 14+ volts still doesn’t tell you if the diodes are bad, that’s a separate test and is critical for AC to DC conversion.
Quick test is set you meter to AC volts and check again with it running, if you read AC volts the diode are bad. New alternator time.
Diodes are one way and when good only allow power to flow in one direction to the battery, if bad it flows both directions to an from so when the engine is not running it will flow in the opposite direction to discharge. So when you check power output you will see good DC voltage but also when the diodes are ax you will also see AC volts.
Quick test is set you meter to AC volts and check again with it running, if you read AC volts the diode are bad. New alternator time.
Diodes are one way and when good only allow power to flow in one direction to the battery, if bad it flows both directions to an from so when the engine is not running it will flow in the opposite direction to discharge. So when you check power output you will see good DC voltage but also when the diodes are ax you will also see AC volts.
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Thread Starter
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Cross-Country
Joined: Mar 2010
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If you are reading 14+ volts still doesn’t tell you if the diodes are bad, that’s a separate test and is critical for AC to DC conversion.
Quick test is set you meter to AC volts and check again with it running, if you read AC volts the diode are bad. New alternator time.
Diodes are one way and when good only allow power to flow in one direction to the battery, if bad it flows both directions to an from so when the engine is not running it will flow in the opposite direction to discharge. So when you check power output you will see good DC voltage but also when the diodes are ax you will also see AC volts.
Quick test is set you meter to AC volts and check again with it running, if you read AC volts the diode are bad. New alternator time.
Diodes are one way and when good only allow power to flow in one direction to the battery, if bad it flows both directions to an from so when the engine is not running it will flow in the opposite direction to discharge. So when you check power output you will see good DC voltage but also when the diodes are ax you will also see AC volts.
Fleet Mechanic
Joined: Dec 2015
Posts: 1,521
Likes: 412
From: Washington Coast
The alternator produces alternating current basically back and forth read as peaks and valley on a scope, read as the max difference or 30 volts. That currentt must be converted to direct current or a straight line on a scope, 14 volts. This what the diode does only letting current flow one way.
The diodes are failing so even though the alternator test 14 volts current will flow both directions through the charging wire, from the alternator to the battery when running and from the battery to the alternator then ground when not running.
The diodes are failing so even though the alternator test 14 volts current will flow both directions through the charging wire, from the alternator to the battery when running and from the battery to the alternator then ground when not running.
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Cross-Country
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Laughing Gas
Joined: Oct 2018
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From: San Diego
Depending on the amp output of your alternator to begin with. Because you are plowing, driving slow, etc. you may need larger output alternator. You probably want to at least get 160 amps or so.
My 2001 came stock with 110 amp alternator.
I finally got smart after buying numerous batteries two, every three years, so I upgraded to the 140 amp alternator 14 months ago.
So far so good.
Check out this supplier:
www.highoutputalternators.com
My 2001 came stock with 110 amp alternator.
I finally got smart after buying numerous batteries two, every three years, so I upgraded to the 140 amp alternator 14 months ago.
So far so good.
Check out this supplier:
www.highoutputalternators.com
Thread Starter
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Cross-Country
Joined: Mar 2010
Posts: 88
Likes: 12
Depending on the amp output of your alternator to begin with. Because you are plowing, driving slow, etc. you may need larger output alternator. You probably want to at least get 160 amps or so.
My 2001 came stock with 110 amp alternator.
I finally got smart after buying numerous batteries two, every three years, so I upgraded to the 140 amp alternator 14 months ago.
So far so good.
Check out this supplier:
www.highoutputalternators.com
My 2001 came stock with 110 amp alternator.
I finally got smart after buying numerous batteries two, every three years, so I upgraded to the 140 amp alternator 14 months ago.
So far so good.
Check out this supplier:
www.highoutputalternators.com