Battery light is on...alternator or battery?

Okay so an interesting story...mom drove my truck into town the other day to get some groceries. She got gas, and went to start the truck back up and it had no power, it flickered, but no power. Long story short, a battery terminal cable had come loose. Fast forward to today (that happened yesterday) and I was driving back from town and went to fire the truck up and my battery light came on. Voltage seems low on the gauge too, it normally hovers dead even between 9 and 19 volts on the gauge, though I don’t know how accurate it is. Wondering if this is my alternator or my battery? Battery is only a few years old and is topped off with distilled water. If it is my alternator, I am having trouble finding a good stock replacement that isn’t reman...I don’t want to get a remanufactured alternator. Any ideas/thoughts?

 

To add, the gauge now hovers just above 9 volts on the gauge. Truck has no issues starting or anything like that.

 

If you haven't already, make sure your post contacts are good and clean.
Even a thin layer of corrosion is hard to see and should be eliminated.

Had this issue on my 2005 and that ended up being the problem.
Replaced the battery, installer didn't clean the posts, and it wouldn't start 2 days later...

 

Interesting. The terminals look corrosion free. I’m not the greatest with car related things, what are post contacts?

 

The two lead studs coming out of your battery.

Run down to the local wally wurld, autobone, O'Reilly's or other hardware store and they should have plenty of these. It's called a battery post cleaner.



You use the pointy end to clean INSIDE the "clamp" that goes on your battery. Once the clamps are off the posts.


Red circle is corrosion. The white flaky stuff on the post. This is bad, but not the end of the world. Just needs a simple cleaning.

Light blue arrow denotes where the pointy part of the brush goes inside of once you loosen your clamp nuts highlighted in pink.

Once your clamps are off you stick the "empty" end of the brush on to the battery posts. The lead things sticking up out of the battery. Twist and it will clean the surface of them. Giving you a better surface for electricity.

There are lots of styles of clamps, and some of the most common are like the two pictured above. A lead clamp like on the left side, and a metal band clamp like on the right side. They both adjust the same way.

Attach pictures of yours, and we can help you further.

 

^ This..

NTB had replaced my battery in my 2005 back in 2008 and 2 days later it wouldn't start.
Had it towed back to them and they said it had a dry cell and replaced it.
3 days later it wouldn't start again.

I took it to O'Reilly's, pulled the battery had them test it, they said it was fine..
As I reinstalled it, in the parking lot, the O'Reilly's chick came out to help me.
She saw the thin layer of corrosion on the clamp and GAVE me a post cleaner.
The douches at NTB never cleaned the clamps when they put the new battery in..

Come to find out, I probably didn't need a battery in the first place, the corrosion in the clamp is what kept it from starting...

2 lessons learned:
1. keep your terminals and clamps clean.
2. NEVER take your vehicle to NTB for ANYTHING....

 

Sounds like the old battery has a couple years on it? Mine usually only last about 36 months (since truck was new). Been reading battery quality is a problem these past few years.

Also like @Tundra2 said check your connections. We’ve had a few members here need to redo theirs from corrosion inside the wire jacket.

Per Alternators: Seems like most on our trucks bite the dust around 200k miles +/-

 

Autozoned replaced a battery on the MzPHM Mobile. Guy wheeled his cart out with the battery. Unhooked old and dropped new in. Wait for it...

He grabbed the wire post cleaner BUT it was loaded with old white corrosive dust from other nasty posts. I said let me have that thing and banged it on the sidewalk to free the powder.

Use some Electric Grease on all your connections.

 

Okay so it really seems like before going after the alternator, robe looking at my connections for corrosion. Not just the outside but the inside of the wire Jacket. Go to the local auto store and pick up some battery post cleaners, electric diode grease (the type that goes into the plugs...where should that be going?) and probably have the battery tested. I also felt like like it was early for the alternator to be going out. I will focus on the battery and then the alternator.

@phm yes my battery is 2-3 years old. It is topped off with distilled water so I initially ruled out the battery. I will have that checked and will clean my connections before I go after the alternator. I will attach pictures soon as well.

 

Truck also has 183.000 miles. I probably should have clarified that already.

 

Multimeter helps with battery diagnosis. They make a special grease for battery posts at auto store. I have a special lube I found on the street corner. Its the Pure Stuff with ‘Cutters’.

 

Yeah. Mine had 171k when new Alternator went in. Opened up and inspected brushes and they were below spec and near the wear divot impression. Truck still ran fine, but it was a matter of time so it was replaced when doing major timing belt work as proper PM.

 

Dielectric grease...not "electric diode grease".

If you were to need an alternator, do not fear a Denso reman. It's the cost-effective choice, and are rebuilt to their standards. No point in buying new copper windings every time.

One of my early lessons in learning to deal with old rattle-trap cars.

 

While you’re at the auto parts store have them test the battery and the alternator

 

Sounds good! I’ll try to have them do all that they can.

 

interesting...

 

Watched to many Scotty videos and believed everything he said.......

 

A proper terminal lube job with NoAlox (electric grease with ‘cutters’) featuring @Coupe Custom Made in USA Battery Hold Down. Support small business.

 

It's a good suggestion to use dielectric grease but not because it conducts electricity.

Dielectric means it insulates or does not conduct electricity. The purpose of the grease is to protect the connection from corrosion. While the grease does not conduct electricity it also doesn't prevent contact because it gets squeezed out where the terminals make contact with each other.

Use dielectric grease because it protects the terminals from corrosion but don't expect it to conduct electricity.

https://physics.info/dielectrics/

 

Here is the shtuff I use on everything electric. Made for Aluminum, but can also be used on Copper and Zinc.

 

I learned about Piezoelectric today thanks to your link.

 

Okay so a little update...still no pics. Went and got a new battery today from the store, and smoke started billowing out from under the hood...truck has no juice at all so it’s getting a tow to the local shop. Thinking some critter chewed at some wires.

 

What did the smoke smell like? Electric Bakelight? Or, oil?

 

Good to know. So, basically you're saying any grease is OK, doesn't have to be special dielectric grease?

 

Grease could be considered a bit of belt-and-suspenders. Clean your posts and clamps periodically. Oh. And dare I mention mixing baking soda and water into a solution and pouring it over the corrosion on your clamps/posts?

 

This is where this can turn into an oil thread and my knowledge runs out of gas. The dielectric grease is still the right stuff to reduce exposure that can increase corrosion. The Noalox mentioned above also seems like a good candidate but I haven't used it. There's chit-chat on the internet about using vaseline (petroleum based) v. silicone based grease but I have a hard time keeping up so I just use the Pematex tube of dielectric grease I have.

One thread on the subject...
https://bobistheoilguy.com/forums/threads/dielectric-grease-alternative.336170/

Google search results...
dielectric grease alternative

 

My dad use to sprinkle baking soda on the tops of batteries to neutralize the acid that escaped via vapor and settled on the top of the battery. This was in the olden days when batteries were vented and he said the acid/residue that settled on top of the battery would create a path that between the battery posts and cause a drain (I've wondered if the baking soda absorbed moisture and did the same).

I have no idea if that was effective and how that idea would endure on the internet today but he was still the best teacher I ever had.

 

I used the Baking Soda on my Original Toy Battery about 15 years ago to clean up the terminals. Worked fine. Still have the same terminals pictured above.

The NoAlox is the best of both worlds for connections. Its like a Silicone in that it excludes air, but also has conductivity with the Zinc ‘cutters’. Sometimes it acts as a grease, as well. You’ll be stoked on it.

 

Truth be told, I gave up using grease on battery terminals when 6V dinosaurs still roamed the earth. Corrosion is rare on my battery terminals unless I have leakage around the posts. For an outbreak of corrosion on battery terminals, my go-to product is that purple spray by Prestone. If you're careful with application, it's not too messy, and it works.

$8 Permatex 80370 Battery Protector and Sealer, 5 oz. net Aerosol Can

https://www.amazon.com/Permatex-803...979&sprefix=battery+corrosion,aps,211&sr=8-15

 

Are you letting this one linger without correcting yourself?