[nicserrentino]

I’ve posted about this but in a different context.
So when I go to start my car, it starts normal and you’d never know I have an issue. And then after all the dash lights do there thing, the battery light comes on and says service recharge system. Nothing changed when it comes to the way the car runs though. No lights are dimmed, it’s not idling rough, nothing.

So I want to say it’s the alternator because when I’m driving, it can cruise in a low gear with the rpm’s around 3k and the battery light will go off.

My car isn’t stock, it’s FBO +cam,flex fuel, pulleys. Weird thing is, this issue just occurred but I’ve had the car back since march.

So I guess the question is, is my issue battery, alternator, or alternator pulley?

Thanks in advance!

[Schlok]

Interesting...I'd get the battery load tested and see if it still performs as it should. This test should also tell you the state of charge of the battery. If the SoC is low, this would be a good indicator of the alternators condition. A PROPER device would allow you to do a charging system test as well and see the ripple in the output voltage as well which could indicate a bad rectifier on the 3 phase output of the alternator.

[radz28]

Do you drive the car much, and do you use a trickle charger? I don't get to drive mine much, but usually keep it on a trickle charger for most of the time. Some automotive batteries can develop a "memory", and if you start changing the way it remembers, sometimes it doesn't like it. I worked at a body shop for years, and customer's car batteries would constantly die. Part of if was moving a lot of them in-and-out of the shop at the beginning and end of the day, but some cars that weren't moved constantly like this, would just have batteries that gave up. They wouldn't even accept a charge.

I'm not saying any of that could be your issue, but, to me, it's stuck in my head to keep some amount of consistency. I noticed, with the car-months-old, that the level of charge would drop a lot, just sitting there. So I started keeping it on a trickle charger.

JMO.

[nicserrentino]

Originally Posted by radz28

Do you drive the car much, and do you use a trickle charger? I don't get to drive mine much, but usually keep it on a trickle charger for most of the time. Some automotive batteries can develop a "memory", and if you start changing the way it remembers, sometimes it doesn't like it. I worked at a body shop for years, and customer's car batteries would constantly die. Part of if was moving a lot of them in-and-out of the shop at the beginning and end of the day, but some cars that weren't moved constantly like this, would just have batteries that gave up. They wouldn't even accept a charge.

I'm not saying any of that could be your issue, but, to me, it's stuck in my head to keep some amount of consistency. I noticed, with the car-months-old, that the level of charge would drop a lot, just sitting there. So I started keeping it on a trickle charger.

JMO.

I drive it when the weather is good. So not too often. But no I don’t use a trickle charger. I did however just buy a battery tender and have had it hooked up for about a day now

[radz28]

Originally Posted by nicserrentino

I drive it when the weather is good. So not too often. But no I don’t use a trickle charger. I did however just buy a battery tender and have had it hooked up for about a day now

I think that's a good start. Hopefully it's not too late for this battery, but it seems this is almost a necessity if you don't drive it much. I might have said a trickle charger, but I meant more along the lines of a tender, like you already have.

It seems to me GM already knew this since these cars have a "storage"-type mode for the battery.

[discgolf01]

What's it say on the dash when the car is running on the subscreen for the "battery" voltage? I say "battery" because its really reading the voltage the alternator is putting out - should be between 13.5-14V - you can also use a multimeter on the alternator output to check as well.

Also check voltage across the battery after the car has been turned off for a while. As batteries age, they will start holding less and less charge after you driven them for at least 30 min or so. You can Google it, but I think 12.25V is something like a half charge.

FYI - if your alternator actually kicks the bucket completely, you'll be running everything off the battery, which in my experience means you got about 20 min to get home before its drained so far it can't keep the engine firing (at least on my old Camaro, haven't had this happen on my 6th gen yet). Its no fun, so something to get ahead of.

[Apexslayer]

Alternator

[nicserrentino]

Originally Posted by Apexslayer

Alternator

So I’d think that too but if I’m driving and I downshift and cruise at higher rpm’s the light goes away. I dont know much about alternators or how they work but wouldn’t that mean it’s working? Or it’s only charging if it’s spinning that fast