Autozone battery testing

Sorry in advance, this question is specifically about our 5th gen 4runner, but I am also a 3rd gen Tacoma owner. Plus this forum is way better! This question is pretty broad and not 4runner specific anyway.

Background: our 4runner has left my wife stranded twice at the gym early in the morning. We park it in the garage at night and the gym is about 5 minutes away. Starts fine leaving the house but won't start leaving the gym approx. 1 hour later. Starter makes a bunch of fast clicking noises. She has gotten somebody to jump her each time and it starts right up. Has started perfectly every other time during the day. Temps in the morning at the gym have been mid 50's. Temps in the daytime have been mid 80's.

I have measured the battery multiple times with multimeter and gotten anywhere from 12.4 to 12.6 volts when vehicle is off. When running, 14 volts. Given that it has started right up both times when being jumped my intuition was the battery is going bad (it is 2 years old Duralast Gold) Took it to Autozone and they tested it and said battery is fine. Their tester said its actually the starter.

My question is how do the battery testers at Autozone work? I'm talking about when he hooked it up to my battery, told me to start the vehicle, and the tester did its test, how does it know that the starter is the problem? Is it just process of elimination (i.e. it knows that battery isn't the problem, alternator isn't the problem, so must be starter)? Or is it more detailed than that? The guy wasn't real knowledgeable anyway and couldn't offer much more help. He had to ask if my vehicle was gas or diesel. Should I put much faith in his test?

We agreed that my wife will drive my truck tomorrow. Glad she knows how to drive a manual!

 

remove the cables, clean the terminals and make sure the cables are tight. im betting the issue is a true connection to the battery

 

The auto parts stores do a load test which a standard home voltage meter cannot do. A load test tells you if you have one (or more) shorted out plates due to crap settling out in the bottom of the battery. You can always try swapping it out with another known good battery if you have one to see what happens. But I concur, clean the terminals!

 

What he said. Especially because I've experienced this on my 4runner recently. The truck would start fine, but the radio would reboot and some other electrical gremlins. Turns out the battery terminal wasn't quite tight enough.

But also, a bad cell in the battery won't be apparent to some of the battery testers. I've even had the one at Interstate say the battery was bad, but down the road it turned out it wasn't. There was a micro-drain on the battery that would only kill it over the long-term. It requires a hard load on the battery to make it obvious. I have an old tester that has ceramic heat sinks in the back and gets pretty hot while doing the load test. I doubt this is your issue, but just food for thought.

 

Picked up a battery terminal and post brush and a can or cleaner/protectant at lunch today. Hope this fixes the problem!

 

I do a poor-man's load test which is to prop the multimeter up on the windshield so that I can read the volt drop when starting.

12.5 volts is healthy enough for a resting battery. It should not drop below 10.5 when cranking.

I agree with the peanut gallery. make sure the terminals are getting good contact.

 

This ^^^^^

If terminals are clean and tight, and you still have problems, I'll guess you drop to about 9v when cranking.

 

Yes, they're SUPPOSED to load test it. Depends on the person though. My friend just dealt with this and I asked her what the idle and load numbers were. She gave me one number. I asked which one, she didn't know..so I explained the process and she said they never asked her to turn stuff on. Told her to try another place and what to do.

 

I do that too.

 

My autozone employs lazy workers. After waiting 10 minutes after purchasing a battery, i told them to give me the tools

 

Buy a

$100 NOCO GB40 1000A UltraSafe Car Battery Jump Starter, 12V Battery Pack, Battery Booster, Jump Box, Portable Charger and Jumper Cables for 6.0L Gasoline and 3.0L Diesel Engines

NOCO GB40 for every vehicle in the household ... even adult children living on their own. It will jumpstart when no one else can be found to help.

 

I was watching a video on YouTube where they were fixing an old truck, head to AutoZone and an attractive women was heading to the counter. The employee sprinted from the back of the store, comment section was hilarious as everyone said l have never had an AutoZone employee run to the counter, lol.

 

There it is, im just an ugly white guy. I need to be pretty to get better service.

 

My wife’s Dodge Durango did this last year, replaced the battery didn’t help, checked terminals by the connections, no issue. The culprit was a cracked positive terminal connector between the post and cable. Found it by just grabbing, putting tension on the cable, a slight wiggle and it would start right up. Might be worth checking.

 

Battery cables are often corroded (especially under the insulation) or cracked.

 

$67 OTC 3181 130 Amp Heavy-Duty Battery Load Tester Black

Amazon.com: OTC 3181 130 Amp Heavy-Duty Battery Load Tester Black : Automotive

The tester I was referring to. Never steered me wrong. Just don't put it down on anything flammable when you're done!

 

I did try this over the weekend but I can't remember what number it dropped to. No red flags that I remember but I think I was looking for 8 or 9 V. Could very well of been around the 10.5 you mention and I thought it was ok. Will try again after I clean it all up and make sure everything is tight.

 

I've seen portable jump starters but didn't realize they came that small. Seems like a worthwhile investment that won't take up much space in the vehicle.

 

They're worth owning. I keep jump packs in every vehicle, including the Miata.

I've never used it on my own car, but I have helped strangers with it. And that's where it's vital. In the past I've had eager-to-helpers grab jumper cables out of my hand despite having no clue what to do with them. And sorry bud, but I'm not risking my highly voltage-sensitive car to your well-meaning but clumsy sparking. That's what I love about them. Self rescue if needed, and no risk to my equipment when I rescue others.

 

Do what auship07 said and I bet you'll figure out that you were wasting your time with the other testing.