Draenor
KILL ALL HUMANS!!!!
What are the CA(Cranking Amps) on the battery? You want something around 800 amps and above.
Engine drags on cold start.
- Thread starter davbell22602
- Start date
B
Bernie
Guest
Most alternators put out at least 13.5-13.8 volts when running. Some put out as much as 14.5 volts. But regardless, 13.25 should be enough (I'd think) to charge your battery.
I'd go to another parts store and have it checked again, see what they say.
Autozone said that it should be 14.5 on the charging system.
Yes & no...
It can get as high as 14.5, even a little over that, depending on how discharged the battery is. Your alternator has an internal voltage regulator that will adjust the voltage as needed to meet the demand. If the battery is fully charged (or seems to be fully charged - defective batteries can do this) then there's no need for a higher voltage and the alternator will just put out enough to meet the current load.
I agree that it sounds like they simply want to sell you an alternator.
Based on the readings you've provided I'd say the alternator is probably fine, and the battery or the starter are the problem.
Draenor
KILL ALL HUMANS!!!!
13.25 is pretty low. It should work, why the truck still runs, but not enought to keep the battery at is fullest potential.Most alternators put out at least 13.5-13.8 volts when running. Some put out as much as 14.5 volts. But regardless, 13.25 should be enough (I'd think) to charge your battery.
I'd go to another parts store and have it checked again, see what they say.
Autozone said that it should be 14.5 on the charging system.
IMO replace the alternator..(or the voltage regulator),make sure you get the 120 amp or better.
ScottyBoy
No, that's not a banana in my pants.
I just bought an Autocraft Gold about 6 months ago from Advance Auto Parts. It was just under 100 bucks with tax and everything. 3 years free replacement warranty and 84 month pro-rated warranty. 
davbell22602
Stihl Chainsaw Man
Autozone just has 105 amp alternator for 130 bucks 100% new.
davbell22602
Stihl Chainsaw Man
Its a diehard B-15 700CCA
B
Bernie
Guest
Dave, what's the voltage at the battery immediately after starting the truck? (You'll need someone to start it while you check the voltage)
I'm betting you'll see a voltage of around 14 to 14.5, dropping down to 13.5 (approx) as the alternator quickly replaces what was drained from the battery while cranking. If that's the case then the alternator is good.
(Oh, and it'll probably drop to 10 or so while cranking, then climb up to 14.5 and then taper off)
I'm betting you'll see a voltage of around 14 to 14.5, dropping down to 13.5 (approx) as the alternator quickly replaces what was drained from the battery while cranking. If that's the case then the alternator is good.
(Oh, and it'll probably drop to 10 or so while cranking, then climb up to 14.5 and then taper off)
davbell22602
Stihl Chainsaw Man
12.50 then drops to 10.15 then goes up to 12.50-13.15. This is on hot/warm engine start.
I have owned several of these, including one in the Tahoe I just purchased, and have had nothing but great luck with them.
B
Bernie
Guest
Costco this past February. $65 each
