Invest in a multimeter


Digital Multimeter

Our family eats through batteries pretty quickly.  Luckily the kids have graduated to hand-held devices with built-in rechargeable batteries, which save me some money and keep batteries from being disposed of prematurely. We still have devices that require the old AA and AAA batteries and my husband came up with a system that helps us maximize our usage of those batteries.

We use a Digital Multimeter whenever we want to check the power in a battery.  This comes in very handy  when we find batteries that have been sitting in a in a gadget for awhile.  Or sometime we have a multi-battery device that isn’t operating and we aren’t sure if it’s because all of the batteries are dead or only one.  Different gadgets require different power levels so just because the batteries don’t work in your digital camera doesn’t mean you should throw them away.

We set the multimeter on the “battery” setting which measures 1.5 volt and 9 volt batteries.  Using the probes to touch the positive and negative poles of the battery you can measure how many amps are left in a battery.  We categorize the 1.5V (4.2 amp) batteries accordingly:

  • New (never used) 4.2 milliamps
  • Almost new 4.1-4.2 milliamps
  • Used 3.8-4.0 milliamps
  • Marginal 3.5-3.9 milliamps

My old Canon digital camera won’t work with anything less than 4.1 amp batteries.  Once the power goes under that it starts telling me to replace the batteries.  Those batteries are still good enough to be used in my son’s Xbox controllers.  My cordless mouse works fine with the marginal batteries and so will a flashlight.

Make the most of those batteries and invest in a multimeter.  It’s easy to do.  My twelve year old daughter’s been using ours for a couple of years now.  You can buy the model pictured here on the Harbor Freight website for only $3.50.  You’ll get your money back in in no time.

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7 thoughts on “Invest in a multimeter

  1. Michele, you “repurpose” non-rechargeable batteries the same way I do, by moving them from high current devices to lower ones as they get used-up. For my family, remote controls tend to be the last stop before my batteries are disposed of in the environmentally appropriate method for their chemistry.

    One should know that different battery chemistries produce different voltages. Here are the most common ones:

    Non-rechargeable:
    * Carbon-Zinc – 1.5V
    * Alkaline – 1.5V
    * Silver-oxide (button batteries) 1.55V
    * Lithium – 3.0V

    Rechargeable:
    * NiCad – 1.2V
    * NiMH – 1.2V
    * Lead-acid – 2.1V
    * Lithium ion/Lithium polymer – 3.6V

    I mention this because most people think of a AAA-, AA-, C-, or D-cell battery as always 1.5V when it’s new or fully charged. This is not the case with NiCad and NiMH batteries, even when new and fully charged.

    This means there is nothing wrong when you replace a dying 1.5V alkaline battery only to discover your new, fully-charged NiMH rechargeable battery measures just 1.2V.

    • Rick
      You understand the underlying principles better than I do. Would you mind if I add your comments as an addendum to my post? I’ll give you credit for them. That will give them more visibility.

      Michele

  2. Michele, Rick,

    I also have been moving to gadgets with built-in rechargeable batteries, using single rechargeable ones for the devices that accept them. I still buy the standard batteries once in a while in case of emergency, but I hate to dispose of them while they still have some use.

    I have been meaning to buy a multimeter for a while, but had no idea what to look for. Reading your information on the values to watch for in the different types of batteries will finally get me to do it!

    • Kelly

      Just stop in your local Harbor Freight store and I’m sure you can find one that’s relatively cheap. Well worth the few bucks it will cost.

      Michele

  3. I use rechargeable batteries – almost exclusively (with the exception of the smoke detector). If you get them by the dozen, they are pretty affordable, and a good charger is not too expensive either. This way, you don’t even have to bother with a strategy to move batteries around: When they are getting low, just drop them in the charger for a few hours, and you are ready to go again.

    Here is one other interesting battery tidbit: Even though NiMH cells only provide 1.2V vs. the 1.5V from a regular battery, if you use them in a device that needs a lot of power quickly (like an electronic flash), they are actually better than good old batteries: The flash will be ready faster for the next shot with NiMHs.

    • Uncharged rechargables are no good when you have impatient tweens and teens looking for batteries. We found the rechargeables just don’t hold a charge as well. My Canon digital camera would always give me a warning to replace the batteries when I had a freshly charged set in it. We do still use them for some devices but we always seem to be in need of batteries when the rechargeables are dead.

      • I have charger that trickle charges four batteries after they are fully charged – that keeps them full and ready for that emergency late night Wii session with drained batteries in the Wiimotes 🙂

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