Battery light blinks
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Tuned
Joined: May 2012
Posts: 332
Likes: 42
Battery light blinks
I recently started to notice on the scan guage a lower than normal battery voltage. Now my battery light is starting to turn on few seconds while traveling down the road. It will only turn on when the truck is cold.
I charged the batteries with a battery charger then rechecked the voltage with a battery meter. At first the voltage was low, then after about 1 or 2 minutes the voltage would get to high 13s to 14. My question is if the altenator is bad can it not charge when cold then charge when it warms up? If it is an altenator is there any particular brand that is better than others?
I charged the batteries with a battery charger then rechecked the voltage with a battery meter. At first the voltage was low, then after about 1 or 2 minutes the voltage would get to high 13s to 14. My question is if the altenator is bad can it not charge when cold then charge when it warms up? If it is an altenator is there any particular brand that is better than others?
Hotshot
Joined: Jul 2005
Posts: 13,834
Likes: 26
From: Middle Tn.
1st things 1st. Have your battery's individually load tested. If good then have the alternator load tested. This is all based on the the fact that you have also checked all battery connections and grounds are clean and good.
Senior User
Joined: Nov 2010
Posts: 477
Likes: 1
When my alternator went out, my battery light would come on and off until the truck was warmed up and going. Then shortly after all that, couple days it would stay on all the time warm or cold. Replaced alternator with a O'reilly 140 amp, first one was trash, light was still on and numbers weren't any higher with testing on a voltmeter than my previous bad one, so got a new free one with the lifetime warranty haha. I would recommend getting a DC power alternator, and new charge cables. Kind of pricey but worth it in the long run. I didn't get one just because I couldn't have the down time of my truck waiting on the new one, plan on ordering one soon though and replacing.
Hotshot
Joined: Apr 2010
Posts: 19,072
Likes: 242
From: Saratoga Springs,UT
This is a GREAT START^^^^
However I will add you can Hydrotest each battery cell and thats from my experiance with my stuff as good a test as a Actual Load test you pull batterys out for at auto parts store,
You can leave batterys in the truck to test them with Hydrometer and a Battery hydrometer is 5 bucks
If everything checks out OK probably Alternator going down hill with a bad diode
Hotshot
Joined: Jul 2005
Posts: 13,834
Likes: 26
From: Middle Tn.
This is a GREAT START^^^^
However I will add you can Hydrotest each battery cell and thats from my experiance with my stuff as good a test as a Actual Load test you pull batterys out for at auto parts store,
You can leave batterys in the truck to test them with Hydrometer and a Battery hydrometer is 5 bucks
If everything checks out OK probably Alternator going down hill with a bad diode
However I will add you can Hydrotest each battery cell and thats from my experiance with my stuff as good a test as a Actual Load test you pull batterys out for at auto parts store,
You can leave batterys in the truck to test them with Hydrometer and a Battery hydrometer is 5 bucks
If everything checks out OK probably Alternator going down hill with a bad diode
Hotshot
Joined: Apr 2010
Posts: 19,072
Likes: 242
From: Saratoga Springs,UT
Funney you mention this I learned the Hard way Once
Went to use it the second time The Hose was Goner and Kinda put the hurt on it
Thread Starter
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Tuned
Joined: May 2012
Posts: 332
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I charged both batteries then took them into AutoZone to have them load tested, and both tested bad. The thing that has me puzzled is the engine never seemed to drag when starting. Would it be a good idea to hydro test them, if so where can I buy a hydrometer? I have been researching batteries and saw oreily has motor-craft I also looked at sears diehard both have 100 months of pro rated warranty. Any opinions on battery choices.
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Logistics Pro
Joined: Dec 2004
Posts: 4,138
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From: South Weber, Utah
You can buy the hydrometer at any autoparts store and I chose the Diehard platinum batteries and have been very happy so far.
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Lead Driver
Joined: Oct 2010
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From: Ouray, CO
X2. The batteries have onine coupons frequently as well. I think i got $40 plus another discount for > $250 order online. Picked up at local store that evening. Paid $174 each if i recall.. huge difference in starting energy!
Hotshot
Joined: Apr 2010
Posts: 19,072
Likes: 242
From: Saratoga Springs,UT
I charged both batteries then took them into AutoZone to have them load tested, and both tested bad. The thing that has me puzzled is the engine never seemed to drag when starting. Would it be a good idea to hydro test them, if so where can I buy a hydrometer? I have been researching batteries and saw oreily has motor-craft I also looked at sears diehard both have 100 months of pro rated warranty. Any opinions on battery choices.
If they Left them in the truck during test thats about the worst way to test them
Im not saying there Good either
Autozone sells hydrometers
Elder User
Joined: Apr 2012
Posts: 904
Likes: 1
I recently started to notice on the scan guage a lower than normal battery voltage. Now my battery light is starting to turn on few seconds while traveling down the road. It will only turn on when the truck is cold.
I charged the batteries with a battery charger then rechecked the voltage with a battery meter. At first the voltage was low, then after about 1 or 2 minutes the voltage would get to high 13s to 14. My question is if the altenator is bad can it not charge when cold then charge when it warms up? If it is an altenator is there any particular brand that is better than others?
I charged the batteries with a battery charger then rechecked the voltage with a battery meter. At first the voltage was low, then after about 1 or 2 minutes the voltage would get to high 13s to 14. My question is if the altenator is bad can it not charge when cold then charge when it warms up? If it is an altenator is there any particular brand that is better than others?
the OEM alternators are POS. the best way to test them,
is to throw them off the pier at the end of D street in the
port of long beach, and if they float, then continue using them.
sounds like you have a diode leaking in the alternator,
and probably have an AC component mixed in with the DC.
diodes, like every thing else, are affected by temperature.
this is why the light going on is temperature related.
usually diodes break down when they get hot... i suspect
the bad diode is opening up when hot, so it's not working
at all, and the remaining diodes are carrying the load.
strongly suggest a DC power alternator. it regulates at 14.8 volts,
so it keeps your batteries charged, and your ficm well fed. this
saves the ficm, and saves your batteries.
i'd suggest changing the alternator, and then see how your *dead*
batteries work.
here is where i went:
https://www.dcpowerinc.com/fit/2006~...07-270-xp.html
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Tuned
Joined: May 2012
Posts: 332
Likes: 42
I started by changing the batteries since both tested with bad cells. Then I started the truck with the same results, so removed the altenator and had it tested. It also tested bad, so I replaced it with a reman from advance auto. It was still under warranty and could not wait for the DC to be shipped. I do plan on ordering a DC in the future when finances allow. The readings in the SG seem puzzle me, when I start up the VLTS stay at about 12.5 then fluctuate up and down. The FLP dies the same although it will go from 10.5 to 11. The FMP will go from 47.5 to 48.5. Once I get on the road the SG will jump to 13.5 and pretty much all other readings go up also. Is this normal, I don't remember my readings being this low before.
Logistics Pro
Joined: Dec 2004
Posts: 4,138
Likes: 7
From: South Weber, Utah
Does the belt have good tension on it? Do you have any aftermarket items that draw more current that stock like a stereo? Did you make sure all of your battery cable connections and grounds are good?
Lead Driver
Joined: Jul 2004
Posts: 6,951
Likes: 512
From: Foothills, CA
Don't forget that the glow plugs stay on after the light on the dash is out. That also can cause the symptoms you describe when cold. I watch my voltages and they drop a bit for the first few minutes and then come up. However my FICM numbers stay good the whole time.
Since you've had this problem there's the possibility of the cascading issue where your FICM might start to go. So keep an eye on the FICM voltages especially the main: should always be in the 47-48 range but I think I've read minimum is 45V. The FICM going can cascade to injector issues.
Don't mean to scare you, just alert you so you can keep an eye out...
Since you've had this problem there's the possibility of the cascading issue where your FICM might start to go. So keep an eye on the FICM voltages especially the main: should always be in the 47-48 range but I think I've read minimum is 45V. The FICM going can cascade to injector issues.
Don't mean to scare you, just alert you so you can keep an eye out...
Thread Starter
|
Tuned
Joined: May 2012
Posts: 332
Likes: 42
Don't forget that the glow plugs stay on after the light on the dash is out. That also can cause the symptoms you describe when cold. I watch my voltages and they drop a bit for the first few minutes and then come up. However my FICM numbers stay good the whole time.
Since you've had this problem there's the possibility of the cascading issue where your FICM might start to go. So keep an eye on the FICM voltages especially the main: should always be in the 47-48 range but I think I've read minimum is 45V. The FICM going can cascade to injector issues.
Don't mean to scare you, just alert you so you can keep an eye out...
Since you've had this problem there's the possibility of the cascading issue where your FICM might start to go. So keep an eye on the FICM voltages especially the main: should always be in the 47-48 range but I think I've read minimum is 45V. The FICM going can cascade to injector issues.
Don't mean to scare you, just alert you so you can keep an eye out...
I have started to watch the main and it never dips lower than 47.5. That is what has me concerned that it may be something else causing the voltage drop.