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Discussion Starter #1
I have a replacement alternator on my 6.0 from O'Reillys and I have noticed on my Livewire that on startup my voltage is 11.5 and after a few seconds it goes up slowly to 13.0-13.4 volts. The highest I've ever seen it go was 13.5 but that has only happened a few times. I was reading somewhere that it should be putting out atleast 13.8 volts, preferably 14-14.4 volts. I need to know if I have a weak alternator and what the voltage output is suppose to be?
 

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Looks ok to me.

Sent from my phone that somebody didn't help me get.
 

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More info please how long does your truck sit before you read 11.5 volts. Might be a battery problem but my truck reads 14.2 volts continuously.
 

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When you first start your trk it should take about 30sec for the alt to kick in.. After that it should shoot up to 13.8 or higher.. 13.5 max dont seem high enough but im not sure what the OK range is.. Mine will shoot up to 14.4 then settle around 13.9-14.2 and stay in that range.

Just keep monitoring it, If you notice your getting a max of 13.5 now just keep checking to make sure you keep hitting that mark. If it starts to drop you know you have a problem. I bet you are in the normal range tho but on the low side.
 

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Discussion Starter #5
More info please how long does your truck sit before you read 11.5 volts. Might be a battery problem but my truck reads 14.2 volts continuously.
Every time I start the truck it shows 11.5-11.6. Even when I start it to Go to lunch from work and I had just drove it to work that morning. I replaced both battery's with Motorcraft factory replacements back in Dec. I was thinking 14-14.4 should be where it rides. I reckon there's always a chance one of them new battery's is weak.
 

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I bet the batts are fine, If anything your alt isnt working right. My last alt would do the same thing yours is doing. After awhile my batt light on the dash would come on every now and then.. It turned out my alt wasnt working right even tho it was tested to be ok.. I put in a new alt and everything works great now. So if I was you I wouldnt worry about it till it gets worse or your batt light comes on.
 

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Discussion Starter #7
Thanks guys. Y'all have answered my question. I am going to start looking for a heavy duty alternator for it.
 

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Dirty Stroke, yesterday I hooked up a DMM to one of the batteries and found out that my Livewire was about .4-.5 lower than what the meter was reading. The other thing is the charging voltage changes with the temperature. On cool mornings I read 14-14.1 and warm afternoons usually 13.4-13.6.
 

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Discussion Starter #9
Thanks Qholic! I noticed my voltage is higher in the morning time too. There's a local alternator/starter shop that said they can build me a 140amp alternator for $85! I think I'm going to give that a try and see how that compares
 

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on start up mine is often 11.5 ish then glow plugs kick off and it goes to 12.5 and after another minute its up to 13.6-14 i normally put her in drive soon as the glow plugs kick off and soon as a hit the gas it pretty much instantly climbs to 13.6-14.1
 

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I have a replacement alternator on my 6.0 from O'Reillys and I have noticed on my Livewire that on startup my voltage is 11.5 and after a few seconds it goes up slowly to 13.0-13.4 volts. The highest I've ever seen it go was 13.5 but that has only happened a few times. I was reading somewhere that it should be putting out atleast 13.8 volts, preferably 14-14.4 volts. I need to know if I have a weak alternator and what the voltage output is suppose to be?
Mine acts identical. I believe that to be normal operation...
 

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forgot to mention that mine is a recent rebuilt one from ford.
 

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Discussion Starter #13
on start up mine is often 11.5 ish then glow plugs kick off and it goes to 12.5 and after another minute its up to 13.6-14 i normally put her in drive soon as the glow plugs kick off and soon as a hit the gas it pretty much instantly climbs to 13.6-14.1
Hmmm see mine never gets that high. I've never seen it above 13.5 and most the time it's more around the lower 13's. I started this whole thread because I've noticed my Airdog 2 has about 5 more psi when it charges 13.4-13.5 than when it charges 13.0-13.1. I've already done the 10 gauge wire and all but I am thinking if I had 14 volts or better then it would benefit the AD2.
 

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Thanks guys. Y'all have answered my question. I am going to start looking for a heavy duty alternator for it.
I have an alternator from Circle K auto parts and it puts out the proper voltage. I'd load check the batteries since the alt is fairly new.

Remember, if you change one battery, change them both.

Sent from my LG-VS700 using AutoGuide.Com Free App
 

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Ecm won't see above 14v. Check at the battery with a multimeter and see if there is a difference.
 

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I put new batteries in mine 02/10. When I turn the key on it reads 11.5 as soon as it starts it reads 12.1 or 12.2 can't remember which right now. Soon as the alternator kicks in it jumps to 14.2. I also noticed that when its completely warmed up it reads 13.8 to 13.9. Original alternator, I just turned 92,000. Its been that way since it was new, or since I had a CTS, I guess I should say (2005 truck).
 

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Discussion Starter #17
I have an alternator from Circle K auto parts and it puts out the proper voltage. I'd load check the batteries since the alt is fairly new.

Remember, if you change one battery, change them both.

Sent from my LG-VS700 using AutoGuide.Com Free App
The alternator isn't fairly new. It was installed when I bought the truck over two years ago. And both batteries were replaced back in Dec with factory Motorcraft batteries. But I am going to check each battery individual just to eliminate a chance of a dead cell.
 

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Thanks guys. Y'all have answered my question. I am going to start looking for a heavy duty alternator for it.
Powerbastards.com is where I got mine, and if you can hold off till black friday, they do have a deal on them, at least they did last year. I'm happy with mine, I have 2, one on my Ex and one on my E250 van. Both have been rock solid, so far.
 

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I remember my scan gauge reads about .5v lower than what my multi meter reads at teh battery.
 
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