What would our lives be like without batteries? Over the last 100 years, our world has become completely dependent upon electricity in one way or another, and increasingly upon batteries in just the last 50 years. Depending upon size, purpose and utility, our expectations of batteries vary significantly with the proportionality of their replacement cost to the value of the device they power. We depend upon small batteries in standard sizes to power things we want to work - digital cameras or a child's toy, as well as things that we need to work - flashlights, garage door openers and smoke alarms. These batteries have long been commodity items. You could buy generic ones in bulk like this pack of 25 that I picked up for $3.50, which averages out at about 14 cents per battery. As such, I'm not surprised that they don't seem to last very long . Alternately, you could buy one of the two premium names in alkaline batteries who battled it out for years in television advertisements over which brand lasted longer in head to head tests. When these are used up, we toss them without much thought. This seems a waste, so a third option is the rechargeable route.
Since the first sucessful electric screw driver, the number and variety of battery powered tools has expanded dramatically. In the last ten years, battery power and technology has improved so that circular saws, drills, impact wrenches - virtually any imaginable power tool now comes in a battery powered version. Generation after generation, the tool manufacturers have come out with higher performance, higher voltage models 7.2 v, 9.6v, 12.0v, 14.4v, 18.2v and now 24v versions. Each generation quickly obsoletes the previous, and the batteries are not interchangeable. Unlike the standardized commodity batteries above, each tool manufacturer designs their own unique connectors and mechanical design to prevent interoperability.
In addition to the voltage arms race, the chemistry of these batteries has evolved. NiCad (Nickel-Cadnium) have been replaced by NiMh (Nickel Metal-Hydride), and now Li-ion (Lithium Ion) in the latest generation of tools on the market. As such, these batteries are not cheap - many are close to $100 each and have a limited useful life of several years depending on usage patterns. If we have a single tool, we may be likely to simply upgrade to a latter generation model with higher performance, higher voltage when it's time to replace the battery. But, if we've invested in multiple tools that shared a common battery style, we may spend the money on a new battery or two every couple of years. These replacement batteries can often be 50%-60% of the cost of the entire tool, and there is no trade in or discount for return of the old battery. Also in the hundred dollar price range are automobile batteries. These are all typically 12 volt, but come in a wide range of physical sizes, amperage ratings (CCA or Cold Cranking Amps), and top or side terminal styles.
The battery that comes in a new car may be covered by the vehicle manufacturers warranty or covered for a reduced interval assumptive that it is expected to wear our like the tires and brakes. Replacement batteries are often sold with a pro-rated warranty typically three to six years in term with free replacement provided for a subset of that time, often the first twelve months. If the battery requires replacement after that first year, the owner pays on a sliding scale. The closer to the end of the warranty, the more the co-payment. A small refund or discount is often provided for the return of the used battery, or "core" to promote responsible recycling of the lead, acid, and plastics. I think this is a good policy model in that it aligns the warranty cost with the performance of the product and provides residual value for the consumer. In contrast to tool batteries which can be 50% the price of the tool or more, automobile batteries are less than 1% of the cost of a new car, and even after the vehicle ages 10 or 15 years, a new battery will likely be less than 5% of the remaining value. The equation for hybrids will be significantly different, and this will be interesting to see how the cost of replacement batteries beyond the vehicle warranty compares as a percentage to the residual value of the vehicle itself. I've explored these other battery, industry, and value ratio models for a reason. We now come around to the batteries which power notebook computers, and like the tool batteries, the chemistry has evolved since the early '90s, moving from NiCad, to NiMh, and now Li-Ion. Each advance in chemistry increased energy density and longevity. Our computers can be made smaller, and enabled to run faster for longer periods of time with more forgiving charge cycle patterns.
Also like tool batteries, the voltage has increased along with number of cells in manufacturer unique packaging designs. With the dramatic increases in computing power, memory, storage, and ever swelling application and OS sizes, when a battery eventually needs to be replaced, is it time to simply upgrade the PC ? While the prices of many of the core commodities within the PC have decreased dramatically, paving the way for steady declines in average unit price year over year, the cost of batteries has remained fairly stable, and this creates some rather dramatic differences in the ratio of the price of a battery to the overall value of the PC within the overall Notebook/Netbook continium. For example, the average X301 ThinkPad costs about $2500, while an option battery costs about $135 or about 5% of the total system. On the other hand, a S10 netbook retails for $359, while an option battery is about $110 or about 31% of the total system. How will these dramatically different cost ratios affect decision making when purchasing a spare battery, or replacing one outside of warranty? Our technological society is increasingly dependent upon battery power, and resultingly I see batteries playing an increasingly influential role in shaping the long term valuations of many of the objects in our lives. Will batteries remain seemingly exempt from Moore's Law?