dead battery problem

[staggerd86c-10]

Whats up guys, i have a question for you that kind of has me stumped. My truck has a brand new battery and i think the alternator is good. My problem is that if i run my truck with the a/c, headlights, radio, basically everything the truck doesnt get into 13v on the voltmeter. Could it be that my alternator doesnt have enough amps to hold the charge in the battery? Its mainly when i turn the a/c on could it be that my blower motor is causeing too much strain?

[old Rusty C10]

its prolly the regulator inside the alternator thats bad so you need a new alternator. if you take it off most auto parts places can bench test it

[73chevyman]

if the battery not getting a charge 1 take your positive cable off if your truck runs altinator is fine if it shuts off altinator bad... 2 if you have a mutimeter handy you should be charging at about 14v with everything on if not then your altinator will be shot... 1 is just a way to check if you don't have a mutimeter handy and i have never trusted the meter in the car cause they seem to me never accurate

[raws67]

I had this problem before in the past and it was my ALT belt in need of adjustment.

[thrtsxchambers]

I recently went through this problem but with 2 battery setup. I found out the air compressor for the air ride needs rebuilt and is pulling to much voltage and the 2nd battery would not stay above 12v and compressor stopped biulding pressure above 80psi. If it drops most with the a/c on I would think it could be the a/c compressor or a part of the a/c system.
just my 2 pennies, I tested everything on the truck and finally thought the alternator could not handle 2 batteries so I put a high output alternator on and nothing changed and finally found out it was the compressor.
Double check everything and get a second opinion before you waste money on unneeded parts.

[staggerd86c-10]

how can i check the blower motor for the a/c? i would like to get this fixed this week but im not sure what i can do to check it.

[ChevyC102007]

Im having a sort of similar problem, one time the volt gauge will show charging, next time it shows a discharge and another it wont even read at all. The belt is new and adjusted properly. The truck still starts normally though, a few times it acted like the battery was dead so what gives? Bad Altenator? gauge or incorrect battery(CA and CCA)?

[cableguy0]

The issue here could be amp draw. Voltage isnt as important as the amp draw. The alternator puts out X amount of amperage. Everything in the truck together draws X amount of amperage. If your drawing more than the alternator can put out. It wont have anything left over to charge the battery. A higher amp alternator may be needed to run everything. As alternators age they will put out less amperage. If everything works ok when its not under heavy load I would suspect a problem with alternator output.

[thrtsxchambers]

I installed a high output altenator and made no difference. Not sure how to check the a/c compressor, best I could say would be to check the voltage on the battery with a/c off then turn the a/c on and see if the voltage drops. the compressor could be pulling to many amps and the battery will not charge while its on. My air compressor needs rebuilt and it is pulling to many amps to run and will not go over 80psi, i'm still waiting for the rebuild kit to get here.

I still think your problem may be from the a/c compressor, not sure if it can be checked at advance or oreillys. Maybe you could buy a compressor from them and if it fixes it then keep it if it don't then return it. I ordered parts online and they will not take a return b/c the item does work but didn't fix my problem.

[misternash2]

i'm not saying i think it's the ac compressor, but if that's a possibility, couldnt you just pull the belt? that would be easiest i'd think...

my guess would be heat sink into the starter. just my hunch. best of luck getting the ole gal up and running again.

also, our local parts stores can check the ALT on the vehicle. just throwing that out. if i suspected the blower motor, i'd un plug it and see if your problem goes away. again, best of luck, buddy.

[staggerd86c-10]

well if the a/c is on the gauge shows about 13v at idle and 14v under acceleration, when you turn the a/c on it drops to 12v or lower at idle. I was wondering if i need a higher amperage alternator because i have electric fans, fuel pump, air compressors, hids in the headlights and foglights, and everything else. so i think with the a/c on its not enough, how many amps is our factory alternator supposed to be? would on of those test at the parts store tell you the amperage being put out? how many amps do you guys think the a/c draws?

[misternash2]

Holy cow. I think you may need a high output alt.if you're running all that stuff together. My local oreillys has a digital tester that displays alt amps. I'm 99% sure it does anyway.

[Intimidator]

You should pull a solid 14v if your ALT is keepin up, and is good.
(Of course we assume you have a good belt and tension?)

I'd start with finding out what the total maximum draw is in the vehicle.

You can measure this with a meter to find out what the AMPERES are with EVERYTHING ON

(It would be nice to know what the AC COMP is supposed to draw to verify if it is good or not, you know, if it is drawing too much.)

Compare that to the size of the ALT.

If the ALT is GOOD, and of the right AMPS, then you're lookin for what is drawing in the vehicle.

It might even be easier to just have a parts store look up a model with the AC and all that, and let you know what the ALT should be for the options, and verify yours matches and is good.

wow, blah blah blah, prolly didnt need to get into all that.

If you're runnin AC, Hi Intensity Lights, Pumps, stereo system/amps, etc etc etc I'd run AT LEAST a 105, but you could probably benefit to run up in a 140 range .

[cableguy0]

Most of the stock alternators where in the 65 amp range. You need at least 105 probably more. You just have way tooo much stuff running in the system.

[gchemist]

84-86 Camaro have 100+ alternators and a V-belt pulley. I ran one for years. Now I use an 08 145 amp alternator! Amps do wonders for power windows!

[73chevyman]

all that crap it's like trying to run your furnance at home with a 2 pole 20 when it needs a 2 pole 40.... if you added all that stuff you either 1 get your altinator rewraped or find a bigger altinator like a 140 or something most shops can get 200 amps out of the stock altinator.... you need to go bigger