A standard AA battery is 50.5 millimeters long and 14.5 millimeters in diameter. It produces 1.5 volts. It weighs roughly twenty-three grams, about as much as a sheet of paper folded twice. In a Costco bulk pack, forty-eight of them together weigh a little over a kilogram — the heft of a hardcover book, or a decent cantaloupe. Most people buy them without thinking much about it. They go in the cart the way paper towels go in the cart.
The size has been in continuous production since 1907, when the American Ever Ready Company first manufactured it for use in early penlights. For the first four decades of its existence, the AA battery was what might be called an informal standard — widely used, commonly understood, but not officially codified. That changed in 1947, when the American National Standards Institute fixed the dimensions and voltage in writing. The naming convention itself had come earlier, out of a series of meetings in the 1920s between government officials and battery manufacturers who were trying to bring order to a proliferating market. They began with A for the smallest practical cell, then moved outward — B, C, D — for larger sizes. When smaller cells were needed later, the alphabet doubled back on itself: AA, AAA, AAAA. Running out of letters in both directions is its own kind of history.
What the standards committee built, whether they thought of it this way or not, was a commons. The word is precise. A commons is something no one owns and everyone can use — a pasture, a fishery, a language. The AA battery became a commons of power. Any battery from any manufacturer, made to the specification, would work in any device built to receive it. The chemistry inside could vary — zinc-carbon, alkaline, lithium, nickel-metal hydride — but the housing stayed the same. No license was required. No negotiation. A manufacturer building a flashlight in 1965 did not need to solve the battery problem. A company making a remote control in 1985 did not need to negotiate with a power supplier. The relationship between a device and its energy source belonged to no one, which meant it was available to everyone.
In 1959, an Eveready scientist developed the first commercially available alkaline AA, which lasted five to eight times longer than the zinc-carbon version it was designed to replace. The devices followed the power. Transistor radios. Portable tape players. Handheld games. Cameras. Each decade brought a new category of device that found the AA battery waiting for it, already standardized, already available at every drugstore and grocery checkout lane in the country. The commons kept growing because the commons was free to enter.
Apple, eventually, decided the idea was wrong.
The iPhone, introduced in 2007, had no user-replaceable battery. Neither did any iPod before it, any iPad after it, any MacBook, any AirPod, any Apple Watch. The power source in an Apple product is sealed inside the device, charged through Apple’s own cables and connectors, managed by Apple’s own software. This is not a cost-cutting measure or an engineering compromise. Apple’s products cost more than their competitors’, not less, and the sealed battery is part of what justifies the price. The company’s founding argument — refined over decades, made explicit in every product announcement — is that hardware and software and power, designed together and optimized together, produce a better result than any open standard can achieve. The AA battery asks nothing of you except that you insert it correctly. Apple has decided that is insufficient.
Tesla arrived at a similar conclusion by a different route. Where Apple sealed the power source to improve the user experience, Tesla sealed it to own the energy relationship entirely. The Supercharger network — Tesla’s proprietary charging infrastructure, built out across highways and cities at enormous expense — is not interoperable with other electric vehicles, or was not for most of its history. A Tesla charges at a Tesla station. The battery chemistry, the cell format, the thermal management, the software that governs charging and discharge — all of it is developed in-house, at Tesla’s gigafactories, for Tesla’s vehicles. The company has spent more time and money thinking about batteries than almost any organization outside of a national laboratory. But the battery it produces is not a commodity. It belongs to the car. The car belongs to Tesla’s ecosystem. The customer belongs there too.
Both companies are making a version of the same argument: that the future of technology is integrated, that the best products are closed products, that power should be managed rather than swapped. They have built that future, or a version of it, for the customers who can afford to live inside it.
Warren Buffett, in 2014, bought the thing neither of them wanted.
Berkshire Hathaway’s acquisition of Duracell from Procter & Gamble was structured as a stock swap — Berkshire exchanged its $4.7 billion stake in P&G for full ownership of the battery company, recapitalized with $1.8 billion in cash. The tax advantages were real and significant; Berkshire had held the P&G shares since the company’s acquisition of Gillette in 2005, and the cost basis was $336 million. A cash sale would have produced a substantial capital gains bill. The swap avoided that. Buffett is attentive to such things.
But the more durable rationale was simpler. Buffett has spent sixty years looking for businesses that are easy to understand, that generate predictable cash, that sell something people buy out of habit. See’s Candy. GEICO. Coca-Cola. The common thread is not glamour but persistence — products whose value proposition does not need to be reinvented, whose customers return not because they have been excited but because they have been satisfied, reliably, for a long time. Duracell has twenty-five percent of the global battery market. It has been the category leader for decades. The people who buy it at Costco are not making a considered choice between competing technologies. They are buying what they have always bought.
The Costco pack of forty-eight is, in Buffett’s framework, infrastructure. Not the infrastructure of data centers or power grids — the quiet infrastructure of daily life, the kind that gets restocked when the supply runs low and otherwise goes unnoticed. Smoke detectors. Remote controls. Children’s toys. Wireless computer mice. Clocks on kitchen walls. The devices that run on AA batteries are not going away, and the economics of replacing them — not just the devices but the habits, the muscle memory, the universal availability of the standard — are formidable. Buffett is not betting that the AA battery will conquer the future. He is betting that it will remain in the present for a very long time.
Two different visions of where technology is going, then, expressed in the form of capital allocation. Apple and Tesla have built sealed ecosystems and asked their customers to enter. Buffett bought the battery for the people who haven’t. The AA cell, fifty millimeters long and fourteen and a half millimeters wide, 1.5 volts, unchanged in its dimensions since a group of manufacturers met in the 1920s to agree on something everyone could use — it sits at the back of a kitchen drawer in most houses in America, waiting for the smoke detector to chirp.
