Battery Basics

April 1998

Timepieces:Education & Repair

Battery Basics

You replace them every day, but do you know what they are? Here's a quick lesson

by David A. Christianson Certified Master Watchmaker

The watch cell, or battery, is a tiny packet of energy that can drive a quartz watch for up to 10 years or more, depending on the size, chemistry, design, quality and efficiency of the watch. The famous "five-year battery" doesn't exist – it's the quality and design of the watch that allows it to run that long on a single cell. Watches operating up to 10 years use a larger lithium cell.

The button watch cell comprises a metal container sealed against leakage. The larger portion is the positive side, and the little button on the bottom is the negative side (see drawing). If you look into your battery cabinet, you'll notice a large assortment of watch cells that vary in diameter and thickness. Some with the same diameter have different thickness; some of the same thickness have different diameters. This variation is due to the watch movement's needs and the outer watch design.

In general, a power-hungry or inefficient watch requires a larger cell to run it for about two years. An efficient watch requires a very small cell to run it for a year or a larger cell to run it for several years. In the vast majority of cases, you can't change the size of a cell already in a watch. That's determined by the watch and movement design.

What's Inside?
The dominant chemicals in watch cells are silver oxide and lithium. Mercury cells are produced overseas but are banned in the U.S. because they create an accumulated environmental hazard.

Silver oxide cells are the most common. They produce 1.5 volts of energy and can remain packaged and on the shelf for three years and last a year or more in the watch. However, you don't know how long they sat at the manufacturer and the distributor.

The smaller silver oxide cells don't have the capacity to power watches designed to run for five years on a single cell. It takes a larger capacity (larger size) cell. That's why you'll find men's watches designed to run the full five years while, with a few exceptions, women's watches are generally too small for the larger-capacity cells.

Lithium cells last longer than silver cells because of their slower deterioration. They tend to be much larger than silver cells but can be very thin.

Handling and Disposal
Silver and lithium cells can explode if heated. Ingestion by infants and children can cause serious illness or death. Exercise care when collecting and disposing of expended watch cells. Collect them in plastic containers with small openings (such as plastic milk jugs). Even though expended, each cell maintains a minute amount of energy. When randomly stacked in a container, the cells can connect in such a way as to multiply their remaining energy and create enough heat to cause an explosion. A plastic milk jug, with its restricted neck opening, can contain any of these potential missiles.

To dispose of expended cells:

  1. Give them to your local solid waste management district or environmental waste collection facility.
  2. Sell them to a battery recycler.
  3. Donate them to the American Watchmakers-Clockmakers Institute's Edu- cation, Library and Museum Trust. Proceeds from the reclamation and sale of expended watch cells are used to train new watchmakers and clockmakers and to fund continuing education programs. Send them (packaged in cardboard boxes) to AWI-ELM Trust, Battery Collection Program, 701 Enterprise Drive, Harrison, OH 45030. The postage is deductible as a business expense. Upon receipt, AWI will send an acknowledgment and receipt.

Next Month: Battery Replacement Procedures and Profits

David A. Christianson owns Christianson Jewelry, Kendallville, IN, and is a director and first vice president of the American Watchmakers-Clockmakers Institute. He is a Certified Master Watchmaker and a Fellow of the British Horological Society. He discusses watch repair in this column each month. Questions, suggestions and comments can be sent to Professional Jeweler, 1500 Walnut St., Suite 1200, Philadelphia, PA 19102, e-mail askus@ProfessionalJeweler.com.






Copyright © 1998 by Bond Communications.


 

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