Battery Repair

Is that battery really dead? You can tell if a battery needs replacing. This Fix-It Guide on battery testing tells how a household battery works, what often goes wrong, how to identify a battery problem, and what parts and tools you will need to fix it. It then gives simple step-by-step instructions for how to test a household battery. See button battery repair for small specialty batteries.

How Does a Battery Work?

A household battery stores electric current that can be tapped when its terminals are connected to each other to form a circuit. All batteries contain two electrodes and an electrolyte; together they produce a chemical reaction that results in a current of electricity.

Small household batteries (AA, AAA, C, D) are also called “dry” batteries because the electrolyte is a paste of powdered chemicals. Alkaline batteries use an alkaline electrolyte. A battery’s voltage depends on the metals that are used in its electrodes and the number of cells. Household batteries produce 1.5 or 9 volts of direct current (DC) electricity, depending on the model.

See also the Button Battery Fix-It Guide for information on the smaller batteries that power watches, calculators, toys, palm computers, electronic notebooks, computer clocks, some cell phones, and many other household items.

What Can Go Wrong with a Battery?

Household batteries work, work weakly, or don’t work at all. They quit working because they corrode, leak, and lose their power.

Fix-It Tip

Because batteries can corrode and leak and harm the very thing they are intended to power, remove batteries from items that are not used frequently.

How Can I Identify a Battery Problem?

  • If a device powered by a household battery won’t work, make sure the batteries are properly inserted, positive to positive and negative to negative. Clean the battery.
  • If a battery looks off-color or shows any sign of flaking or corroding, replace it with a new battery.
  • If a battery looks okay, gently polish both ends of the battery and all of the contacts inside the battery holder with a silver polishing cloth, pencil eraser, emery board, or fine sandpaper; don’t touch the cleaned areas.
  • If the device still won’t work or works sluggishly, test the batteries with a multimeter (below), or with the self-tester on the battery. Replace any batteries that test low. If the device still won’t work, the problem is more serious than batteries.


Do not recharge household batteries except those that specifically say “rechargeable.” And recharge them only in battery recharging units. See Battery Recharger.

What Do I Need for Battery Repair?

Here’s what you need to test, clean, and replace batteries, all available at hardware stores and home centers:

  • Multimeter
  • Silver polish cloth
  • Pencil eraser
  • Emery board
  • Replacement batteries

Fix-It Tip

What’s the most important factor in buying replacement batteries? Expiration date! Dollar for dollar, alkaline batteries with a distant expiration date (fresher battery) will give greater value than an expensive battery that will expire sooner.

What Are the Steps to Battery Repair?

Test a household battery:

 Heating Element Repair

Make sure the battery voltage is at least 90 percent of the full-charge rate.

  1. Check the side of the battery to determine its DCvoltage. Commonly, AA, AAA, C, and D are 1.5 V, and rectangular batteries are 9V.
  2. Set the multimeter to the VDC (volts of direct current) scale.
  3. Touch the red multimeter probe to the battery’s [+] terminal and the black probe to the [-] terminal. If the reading is more than 10 percent below the rated output (1.35 V or 8.1 V), the battery is bad and should be replaced.

Fix-It Tip

Always replace batteries in a device as a set. That is, if a device requires four AA batteries, replace them all at once because one low battery can drain the others or still not power the device. You can mix brands, but not battery types such as alkaline and dry cell. Never mix sizes (AA and AAA, for example).