# Is the Autozone battery tester reliable?



## treesloth (Jul 27, 2018)

So, our Grand Caravan decided not to start. We've had it for about 4 years, and it's a 2012. So, it's possible that the battery has simply lived a good life and shuffled off this ignition coil. But, just to test, I stopped at the Autozone because they claim to be able to test it. Nice, right? But what the guy told me didn't make sense. Maybe I just misunderstood.

Anyway, we pulled up to the AZ after having driven for about 25 minutes, but having required a jump start to get started. The AZ guy hooked up his handheld test device, put the CCA value from the battery into it, and started the test. A short time later it said that the battery was dead. I think it might have also given a temperature. While it was testing he told me how it worked... Apparently the device attempts to pull from the battery a charge of a magnitude determined by the CCA value entered into the device. He said it was about the same power needed to start the car. If it can't draw that power it says that the battery is dead. But, funnily enough, right after he told us it was dead I reached in and started it with no problem. So, a dead battery that had just been partially discharged by the device had no problem starting the car. That seems odd.

Maybe I misunderstand, or maybe it's a valid test and I should just expect more trouble but the guy explained it wrong, or maybe it's just not legitimate. What's the deal with those testers?


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## mark sr (Jun 13, 2017)

I suspect the guy used the wrong terminology, the battery probably showed up bad in the test - not dead. I have a cheap battery load tester I use and it's worked well for 30 yrs. It doesn't tell you exactly what is wrong but gives a good indication of how stout the battery is. It's best to charge a battery first, a discharged battery can show bad even if it's not.


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## Gregsoldtruck79 (Dec 21, 2017)

If the battery is 5 years old....just figure on getting a new one. And the days of paying $75 for a good car battery, are over. :sad:


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## Itrim (Jul 15, 2018)

Gregsoldtruck79 said:


> If the battery is 5 years old....just figure on getting a new one. And the days of paying $75 for a good car battery, are over. :sad:


Walmart sells a perfectly good battery with a 5 year prorated warranty for about $90.00.


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## Gregsoldtruck79 (Dec 21, 2017)

Itrim said:


> Walmart sells a perfectly good battery with a 5 year prorated warranty for about $90.00.


I know, when my 5 yr. old Walmart battery died two months ago in my Jeep, none of the wally's close to me had them in stock . (post big sale run on them I guess) and the stores were waiting for new shipments to come in. I had to have a battery, so I went to AA and paid $156 for their Gold series battery. Ouch.. ouch..


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## Bigplanz (Apr 10, 2009)

I got a $75 battery at AZ for my Navigator back January. If i get 2 years out of it, i will be happy. So far, so good.


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## bfletcher7 (Jan 16, 2016)

I'm not a mechanic, so take this with a grain of salt and if others know I'm giving inaccurate detail then correct me. First, you can visit web sites of charging system analyzers and read how they operate. I know Midtronics makes some. 

All of this is a moot point if you already bought a new battery and all has been well for several days. But you probably know there are other components that can lead to a no-start condition. This include the alternator and starter (including its solenoid). Then, too, there could be some other electrical issue that is draining the battery. That's why it's important that the analyzer check the entire loop because any one of them can cause the battery to appear weak. 

If you have a DVM you can at least see if the battery is strong enough to get the alternator going. If you measure 12.2 or greater across the terminals then you could start the van and take it to 2,000 RPM. Doing that places a load on the battery and will boost the alternator and if it is working properly your voltage should climb to 13V+. Varying RPM's should take it as high as 14.xV. If there is no voltage climb then it would seem to me the alternator is not functioning. I am less certain how to check the starter and its solenoid. 

I have never replaced a battery just because it is 4 years old.


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## Bigplanz (Apr 10, 2009)

I got this tested a couple years ago. It works well.

https://www.amazon.com/ANCEL-Profes...32785954&sr=8-3&keywords=ancel+battery+tester


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