battery test at Advance

I'd gotten the free battery test at the tire dealer's last week, and they'd told me my battery was weak.

Not being the trusting kind, I went to Advance Auto today - and their check said my battery was "good". Is it safe to assume that the tire dealer wasn't telling the truth, or are there legitimate reasons why their test could have said my battery was weak?

Also, the pr Voltage: 12.74 CCA: 502 Rated: 600

How can the device know the rated amps? Or was it that the guy read it off my battery and entered that number into the device? (It's the original Delco, if that matters, on a 2002 Century, with a low number of starts.) Thanks.

Reply to
Tom
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That 12.74 volts hints at a high charge level.

In my experience, battery tests can be very unreliable, especially if the tester doesnt have the right equipment and the right techniques. I spent a fortune one winter on jump starts, while the battery test was telling me the battery was good.. It wasnt at all good.

Some places might fudge the truth to try to sell you a battery, others might just miss a diagnosis, and then there exists the possibility that the battery IS weak.

Reply to
hls

A battery that old should be replaced even if it tests good. First real cold day it'll probably leave you stranded.. any battery over 4-5 years old is buying time nowadays.

Reply to
m6onz5a

A battery that old should be replaced even if it tests good. First real cold day it'll probably leave you stranded.. any battery over 4-5 years old is buying time nowadays.

**** Very true... I intended to add that to my post but pushed the button prematurely. Good counsel.
Reply to
hls

Also the proper way to test a battery is to fully charge it first then load test it etc. I bet that didn't happen. :)

Reply to
m6onz5a

Did either one of them actually open the battery caps, put in a hydrometer, and look at the specific gravity of the fluid? Or did they just connect a load tester that they didn't understand, push a button on the load tester, and believe whatever the load tester said?

The load tester puts a big resistive load across the battery, and sees how much current the battery will actually deliver into that load. This information is useful but it's only a tiny part of the story. The rated number could have come from anywhere but HOPEFULLY he read it off the side of the battery instead of looking it up in the book that says what rating the car came with.

If you haven't seen any trouble starting, I wouldn't worry about anything. When you start having clear indications of battery trouble, get a new battery.

--scott

Reply to
Scott Dorsey

If the battery is about four or five years old, and if you live where the weather gets really cold, replace the battery with a new highest amperage battery which will fit in your vehicle.New batteries (battery plates start sulphating (wearing out) as soon as they are being used. cuhulin

Reply to
cuhulin

A battery that old should be replaced even if it tests good. First real cold day it'll probably leave you stranded.. any battery over 4-5 years old is buying time nowadays.

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My battery lasted for 8 years.

Reply to
Bob Jones

You are damned lucky.. They often do not last 4-5

Reply to
hls

As mentioned in another thread, the Wife's Avalon is a '97 and still on the original battery. I check the cells every once in a while and it's showing no signs of wanting to give up any time soon. It's lasted quite a few MN winters being kept outside, too...

Reply to
Jules

Jules wrote in news: snipped-for-privacy@remove.this.gmail.com:

Cold climates are kind to car batteries.

If your area rarely experiences ambient temps above 85, you keep the cells topped up and never let the battery go flat, eight to ten years is easily possible before the unit refuses to hold a full 12.65V charge.

My recent personal experiences: OEM Panasonic: 11 summers, 10 winters Aftermarket Interstate: 8 summers, 8 winters

Reply to
Tegger

I commonly get +6 years on a battery, and can't remember getting less than that. Usually that's about how long I keep a car. I check the acid level about once a year and bring it up to the rings if it needs it. Always use tap water. Lake Michigan. Yeah, I know. Then I wipe it down. Heard long ago that the acid/oil/dirt slime that collects on the battery can provide a discharge path. My cars are always well tuned and start right up. And I don't have amps and a boom box. Anecdotes.

--Vic

Reply to
Vic Smith

Check charging voltage hydrometer test load test (voltage not to fall below 10.4) and you should know all you need to know. and use distilled water only for electrolyte replenishment.

Reply to
Nicholas

You can buy a voltmeter or VOM these days very cheaply. Then you are not dependent on shops- I wouldn't put it past most shops to bend the results a little in their favor.

Since you need to check the voltage under load, use the headlights or the starter as a load. It is best to do it with two people, but you can do the test with one. Use clip leads between battery terminals and the meter test probes. Make sure the leads are secure and cannot touch each other, since the starter motor will cause some vibration and shaking. Position the meter so you can see it from driver's seat and then turn on lights or try to start the car, and notice how much the meter dips.

Reply to
Don Stauffer

I like the battery that came with my car. It has 3 indicators on it for good, bad, and charging. Too bad the dealers don't sell them as replacements.

Reply to
Bob Jones

Both of these methods work on a fully charged battery.

This result came from a digital tester. Operator enters cca specs (printed on battery) Very small load and reasonably accurate even at low charge level Kinda like this:

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I've gotten 6 or 7 years out of delco batteries, but they fail suddenly and completely at that age.

Reply to
ben91932

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