Batteries have been with us for a long time. They provide portable, convenient sources of energy for powering devices without wires or cables. Battery selection should be based upon factors such as application, cost, convenience, rechargeability and availabilty. The information shown here has been gathered from a wide variety of sources to answer, hopefully, all your questions about batteries. We will also point you in the right direction to find suppliers of specialty batteries, and rechargers made to give you the maximum life from your existing batteries. So if you want to know all about batteries, from their history of development, comparison of types, chemistry, new developments, construction and application, and environmental concerns, just use the convenient navigation bars at the left side of the page.
What is a primary battery? What is a secondary battery?
A primary battery is most likely found in a drugstore, whereas secondary batteries are not generally found there. Lift up the hood of your car if you want to see a secondary battery. Secondary batteries are designed to be charged and discharged repeatedly many times. (For instance, every time you start and drive your car.) Primary batteries are designed to be used only once. However, the distinction is becoming less obvious, as we shall see later. Even the garden variety of throw-away alkaline batteries found in the drugstore can be recharged safely and conveniently many dozens of times!
Why do my batteries run out of power so quickly in portable devices?
Summed up in one word, the answer is weight. Those who design these devices are faced with difficult decisions. How can we make the device have long operating time, yet keep the weight down? A bigger battery will contain more energy to make it last longer, but will the market stand for the added weight? What is our competition doing? If the competition has switched to a more exotic type of battery, Lithium-ion or Nickel-metal Hydride, then they are forcing the customer to use more expensive replacement batteries, which may not be easily replaced. A specially-designed charger would have to be included with the product for these specialty batteries, and that drives up the selling price of the product even more. And these chargers are not usually interchangeable with any chargers the customer may already have.
The power supplied by the batteries to your digital camera, your MP3 player, or your radio, multiplied by the time the power flows, equals a certain number of Watt-hours. Are you familiar with the electric utility meter on your house or apartment that registers the number of Kilowatt-hours you and your family use? The utility then bills you for the quantity of energy (kilowatt-hours) that you use. Batteries don’t store power, they store energy. Did you know that? When you buy a battery you are paying for the energy it contains, and at a premium price if the technology behind the battery is new and therefore it is lighter than expected.
The amount of energy stored in a given battery depends, not only upon its weight and volume, but upon the materials and construction of the battery. For instance, you can count on any brand of alkaline battery to have within it about 4 times the energy of the old-fashioned carbon-zinc battery. Those carbon-zinc batteries are still around in packages labeled “heavy duty” or “transistor power”. (Beware when you are buying batteries — look for the word “alkaline” on the package.)
In high-drain applications such as toys, cameras, and CD players, carbon-zinc batteries will not be able to provide that one-quarter energy of alkaline batteries of similar size. They will yield only a little more than a quarter of that quarter, or roughly 10% of the alkaline’s energy. This figure is frequently quoted when comparisons are made in battery commercials on TV. “This new improved battery lasts 10 times longer than ordinary batteries.” Guess what kind of ordinary battery they are comparing it to!