I've been suspecting that my batteries were getting weak, so I stopped at Autozone to have them tested.

He checked both batteries separately and then the charging system. Both batteries checked out good, as did the charging system.

Is the testing meter that these stores use, which actually looks like a very good unit, very accurate?

The batteries are somewhere around 4 years old. The truck only gets used from October thru May here in SC.

 

Midtronics would probably be the best brand for this, but whatever they have is probably accurate enough in terms of what it reports. We could argue for years on methods and digital versus carbon pile and a dozen other details that probably only move the CCA result of the test a couple percent. The real problem is WHEN the batteries are tested.

After a battery is charged it needs to rest for 6-12 hours to bleed off the surface charge (or have one of several other processes applied) or it will test higher than it really is. If you drive the truck to the store.... the battery just went through a starting load cycle (which on the 6.0 is worse than a gasser because the GP cycle) and some form of a partial charge cycle. Pretty much guaranteed inaccuracy there.

The correct way to do it is to pull the battery from the truck, charge it fully, take off the surface charge, check float voltage, THEN load test it, then check the float voltage again after the load test. The process takes a solid day if you don't use a load to bleed the surface charge, and you can't use the battery to start the truck in the middle of it and let it partially recharge from the alt.

In terms of your charging system, if it's a 6.0 with either a 110A or 140A alternator.... the charging system is by definition not up to spec Running voltage and a clamp meter can confirm your alternator is doing what it can, but using a battery tender and rotating positions is about all you can do with stock rated alts and stock cabling.

I bought a Solar so I don't have to mess around with going to the parts store. In the 6.0 scheme of things it's not an expensive tool to purchase:


At this point, what's cheaper? A Solar BA-7, a battery charger, a couple days, maybe some new batteries at the end of it all? Or a call to FICM Repair for a new alternator and a rebuilt FICM because the parts store said "nah, you're good"?

 

There's checking out good to the pass/fail, then there's the capacity. Did you get a printout or CCA numbers for each battery?

 

That is a good point. I had my FICM replaced just after I bought these batteries in 2014. I replaced my alternator last summer with a 110 amp unit. It was an emergency and I had no choice but to get a 110 unit, unfortunately.

TooManyToys. He didn't offer a print out. I just may mosey back there and have them re test it and get a print out and post it back.

I m thinking of picking up a pair of Interstate batteries from Costco. click here

 

45 pounders.

 

I had to buy a new battery a couple months ago so I went to AutoZone and got one. I had also recently been hearing a whinning coming from under the hood and thought maybe it was failing bearings from a pulley. Then I thought about the dead battery and hoped it wasn't the alternator so I went back to AutoZone and they hooked it up and said the battery was so low it wouldn't even register on their thingamijig. So I bought a alternator and have been procrastinating putting it in. On a chance I went to O'REILLY'S and had them check the battery....they said battery was great but the diode's in the Alternator were bad. Unbelievable.

 

I had Autozone tell me my batteries were good, but the alternator was bad. I went back to the shop where I got the alternator (it was still under warranty) and we put it on the bench for testing, and it was perfectly fine. I went to Costco to get a couple of the Interstate batteries since they are one of the few that offer a FULL replacement for 3 years, vs 2. And they replace both, not just one.