Inexpensive battery test equipment

Discussion in 'The Okie Corral' started by Mr981, Nov 1, 2010.

  1. Mr981

    Mr981

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    Our toy is getting ready to get laid up for the winter so it's been on the trickle charger a lot these days.

    Seems like the trickle charger is on constantly; Had it on the road at highway speeds for 40 miles figuring that should bring it up to full charge but when I plugged it in at home when I returned the light on the charger came on and is still on 2 hours later.

    The battery is five years old and I'm wondering if it's starting to fail to hold a charge; the car started with out laboring and no idiot lights when I had it out, FWIW.

    Can anyone recommend an inexpensive battery tester to determine the condition of the battery?
    thanks for any help with this.
     
  2. Santa CruZin

    Santa CruZin Searching

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    Drop one of these across it.

    [​IMG]

    But seriously, any Auto Zone or similar car parts store should be able to test your battery for free.
     

  3. robin303

    robin303 Helicopter Nut

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    Any auto store will test it free or go to Radio Shack and get a tester for about $10.
     
  4. Brian Lee

    Brian Lee Drop those nuts

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    I'll assume you are talking about lead acid batteries of the automotive type, but maybe smaller - on your "toy".

    Very few batteries I've had actually made it to the age of six, in spite of being claimed to last for 7 or 8 by the manufacturer. I'd just replace it anyway before it gives out unexpectedly.

    Car batteries cannot be tested right without putting a heavy amperage load on it while you simultaneously watch the voltage, and this requires a tester that has a very large resistor of the proper value inside it to load the battery with. Just checking the voltage with a 10 buck voltage tester will tell you nothing about how well it holds a charge. Even fried lead acid batteries will often show 13 volts or more under no load, and Radio Shack doesn't even sell a resistor big enough to properly load a battery of that size.

    You'll have to go to an auto parts store to get it tested right. The device that does the testing is kind of large and usually mounted on a wheeled trolley to wheel it out to your car.
     
  5. Ol Timer

    Ol Timer ↓ hog hunter ↓ Millennium Member

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    Yep, Autozone can do a load test, no charge. :cool:

    You can test it for a dead or weak cell yourself with a volt meter. Pop the caps and connect one lead on one terminal and dip the other lead in individual cells. It should read 2-4-6-8-10-12 or thereabouts when working away from the terminal with the lead attached.
     
  6. Adjuster

    Adjuster

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    Also if you have one of the new 'smart' trickle chargers it is going to run itself thru a series of steps that can take several hours before it ever brings the battery up to full charge. Desulfation and that kind of stuff. Did you completely disconnect the battery from the car? Parasitic draw from your radio, clock or anything else using power may be too much for a very low voltage trickle charger.



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    Last edited: Nov 1, 2010