The hook is a recent Habr breakdown of how DeWalt, Milwaukee, and Hilti came to resemble big compatible building blocks. And then, right in the subheading, a fact that refutes it: those blocks are not compatible with one another. A Milwaukee battery won’t fit a DeWalt, you can’t clip a Makita battery onto a Hilti—while within a single brand, everything snaps together with everything else: batteries, cases, radios, cloud services. It reads like a software story about lock-in, but it has one detail I couldn’t leave without an independent check: the wording of an actual American patent under which Milwaukee had been collecting licenses from the entire industry since 2009. Not “a method for a lithium-ion battery,” not “a cooling system,” but, once you filter out the legal language—a lithium-ion battery for a handheld tool capable of delivering an average discharge current of approximately 20 amps or more. Milwaukee’s June 30, 2009 press release confirms it verbatim: “battery packs capable of producing an average discharge current greater than or equal to approximately 20 amps.” The patent office reviewed this thing for obviousness a dozen times—and every time said: yes, it is non-obvious. Jury trials added zeros to the plaintiff’s bills. The patent expired on November 24, 2023, and after that date begins the most interesting part: what was left of the industry when the main moat dried up.
Black & Decker built the first cordless drill back in 1961—NiCd, heavy, stinky, but capable of handling drill currents. The idea of “one battery for the entire line” is older than it seems, too: by 1987 Makita had fifteen tools running on a 7.2-volt battery; Ryobi launched its 18-volt ONE+ platform in 1996; and—here’s the detail that makes DIYers drool—a ONE+ battery bought today fits a tool from twenty-six years ago. Thirty years of compatibility on a consumer platform, more than three hundred items in the catalog.
The real shift came when lithium entered the tool world. NiCd could deliver tens of amps without complaint, but early-2000s laptop 18650 cells sagged under currents in the tens of amps—a drill built from them would turn into a space heater. The first workable pairing came together in 2001–2003 between Milwaukee and Canada’s Moli Energy, which made IMR26700 lithium-manganese cells: rated at 3 Ah and capable of delivering one hundred amps in a pulse. In January 2005, Milwaukee unveiled the V28 line—the first full line of professional lithium-powered tools, according to the cell supplier; that autumn, on October 3, Makita launched its 18-volt LXT, which is still alive today; in 2007–2008 Milwaukee added M12 and M18; in 2011 DeWalt moved from “stem” batteries to slide packs. That was also when a classic of the genre was born: rename an 18-volt platform 20V MAX. Five 3.6 V cells make 18 volts, while “20” is the initial no-load voltage, as the asterisk on the website candidly warns. A company manager explained the name in 2011 this way: “to reduce consumer confusion.” The two-volt gap is not real: DeWalt itself sells the DCA1820 branded adapter, which puts “20-volt” batteries on old 18-volt tools.
Now for the meat. Patent US 7,554,290—a foundational document with priority from November 22, 2002, issued on June 30, 2009. And for context: by then TTI—the Hong Kong owner of Milwaukee since August 2004, having bought the brand from Atlas Copco for 626.6 million—already had Ryobi with its “one battery for thirty years.” It was just that this philosophy had been for the backyard market, and now they were moving it into the professional segment—and the legal cover for that move was already sitting at the patent office.
The family of three patents (’290, ’173, ’510) held claim language that the appellate court decision calls the “20-Amp Limitation”: cells in the pack must be capable of delivering an average of approximately 20 amps over their full rated capacity. Not a specific chemistry, not a circuit, not a BMS—the bare fact of high-current lithium in a handheld tool. Starting in 2009, Milwaukee began granting licenses to “major players in the industry”—the wording from its court filings. In October 2009, global Makita signed with Milwaukee (the terms are confidential, but LXT continued to be made afterward); in 2012, Hitachi Koki got hit with a lawsuit. In October 2014, Milwaukee brought eight companies into court at once: Hilti, Snap-on, Festool, Chervon, Positec, and others. The defendants mounted the standard response—nine IPR proceedings at the patent office, attempting to kill the claims for obviousness—and lost on every front: on February 16, 2018, the Federal Circuit left all three patents standing. The decision is self-critical over one legal detail—it corrected the omitted word “average” in the construction of the claims—but merciless on the substance: in the combinations of prior art proposed by Snap-on and Hilti, the 20-amp threshold was “not even achievable,” and so the non-obviousness of high-current lithium in 2002 stood.
But the loudest moment came earlier. On October 26, 2017, a Wisconsin jury returned a unanimous verdict on five claims across the three patents against Snap-on: $27.8 million in “reasonable royalty” damages. During arguments, lawyers worked it out to three and a half to four dollars per pack sold; the judge refused to treble the amount the plaintiff had requested. There is a particular irony here: Moli Energy, which had once made cells for Milwaukee V28 batteries, came to develop packs for... Snap-on after its exclusivity ended in 2006. The very same Snap-on that later got hammered by a verdict over its packs.
The patent expired on November 24, 2023. But something important happened during the fourteen years it was in force: none of the leaders attempted to create a shared connector. Makita wound down its 2009 36-volt line because users were not moving away from LXT—a quote from its own press release—and in 2019 announced XGT, another subsystem incompatible with LXT. In 2016, DeWalt introduced FlexVolt—a fifteen-cell battery that switches from an 18-volt configuration to a 54-volt one when installed in heavy-duty tools. Beautiful, but inside its own connector. In 2022, Hilti assembled Nuron, a 22-volt platform with a SIM card in the charger, where telemetry uploads itself to the cloud. In TTI’s 2024 annual report, margin rose to 40.3%, and the explanation includes three things: Milwaukee’s share, new products, and—verbatim—“aftermarket battery sales,” the sale of batteries separately. And the CEO’s 2023 statement contains a line worth memorizing: “Unlike competitors, we have not changed our battery interface and compatibility, enabling our bare tool business to thrive.”
Here, though, it is worth being honest: blaming everything on greed is a convenient one-dimensional model. Let’s break down what gets in the way.
First, electronics. A connector is not “positive, negative, and a piece of plastic”; it is a network whose BMS logic is spread across the battery, the tool, and the charger. The receiving side needs to know what current to permit, when to interrupt discharge, how to read pack identification. Since 2018, the industry association Power Tool Institute has explicitly said that cross-brand adapters can bypass protective circuits and end in overheating or fire—and that is true; no-name AliExpress adapters really do live with that risk. But what is missing from PTI’s position is any word about making the connector common, so that adapters are no longer needed. The institute consists of Stanley Black & Decker, TTI, Hilti, Makita, Bosch, Festool, and Stihl—the club of lock owners is somehow in no hurry to advocate for lockpicks.
Second, engineering: manufacturers really do design a tool around the rated curves of their own batteries. ToolGuyd’s reviewer has argued for years that money is not the main barrier, but control over the quality of the experience: a universal pack does not guarantee rated currents, the saw will misrepresent its power, and the tool will get blamed. He has practical proof—Makita XGT distinguishes “foreign” batteries from native ones and throttles them. A counter-case that has to be acknowledged.
Third, economics—and one TTI report alone is worth a separate lecture on marketing. A platform with an unchanged interface is a conveyor belt for repeat purchases: a dead battery gets bought as a separate part, while a bare tool—a tool without a battery—sells cheaply, and it sells cheaply because you already own the batteries. It is the same mechanic as printers and cartridges: a Makita XGT kit with a saw and two batteries on sale costs $299; two of those batteries separately cost from $398. The batteries in the kit come “free.” You pay later, once the fleet has grown.
And fourth, regulation. The European common-charger directive—the one that gave the iPhone USB-C—does not mention power tools at all. The 2023 Batteries Regulation requires removability and replaceability from 2027, but says nothing about compatibility across brands: batteries are already removable, the formality is satisfied. A standard does not emerge by itself—it is written by whoever benefits from it, and the only one who benefits is the consumer, who is not in the room.
The clean way to test whether the issue is the battery is to look at the neighboring segment: boxes, where the same “ecosystem” logic exists but the locks work differently. Modular cases have been rolling through the professional tool market for more than thirty years: the systainer was invented in 1993 for Festo/Festool; behind it stands the subsidiary Tanos, and Tanos licenses its system to direct competitors—Makita MakPac cases are molded with “Licensed by TTS/Tanos,” and they stack with Festool. In 2010, Bosch released L-BOXX under a Sortimo patent that explicitly cites the earlier Tanos system as prior art; later Bosch and Sortimo formed a 50–50 joint venture. The American pair ToughSystem (DeWalt) and Packout (Milwaukee) were both designed in Israel by two competing firms, ZAG—bought by Stanley in 1998—and Keter, which makes garden furniture and sheds and co-authored the foundational Packout patent. Cases flow between brands because they are made by outside factories that benefit from selling to everyone.
But don’t rush to conclude that “cases are open love.” In 2024, Milwaukee and Keter filed with the ITC against Klein Tools over the MODbox system, which interfaced with Packout. And here is the freshest development: on October 2, 2026, the Commission issued its final determination—violation on two of the three patents (’026 and ’952), with a limited exclusion order and a cease and desist order against Klein; the third patent (’167) remained in limbo until November 2, 2026. Klein has already discontinued some of its larger boxes and redesigned the system. The interlocking latch is patented and protected—but inserts and mounts that simply hook onto Packout, nobody touches. The border is closed exactly to the thickness of the latch, no farther.
Yes—and they are the best counterexample to “technically impossible.” In 2018, Metabo assembled the Cordless Alliance System—now more than 50 brands and 500 tools on one battery; Bosch opened the consumer Power for All platform—Gardena, Husqvarna, HK Audio, and, don’t laugh, Emmaljunga baby strollers powered by a screwdriver battery—and for professionals, AmpShare since 2022: 35 brands and 430+ tools. Technically—it works. Look at the lineup: Metabo, Fein, Rothenberger, dozens of niche players. DeWalt, Milwaukee, Hilti, and Makita belong to none of them. There are even companies that belong to two alliances at once—Rothenberger is a CAS founder and an AmpShare co-founder simultaneously—but no major manufacturer is in them. An alliance is the “platform as product” model: you monetize the battery directly by selling it to everyone. The big four run the “platform as lock” model: the battery monetizes the tool fleet you bought earlier. The second model delivers higher margins, and it is maintained precisely by those with a large installed customer base.
The patent is dead, the cell was commoditized long ago—the 21700 format came down from the EV industry—and the number of brands in alliances is growing. But the interface remains, and here is why: the interface is the last moat, one that does not grow out of technology but out of the years-long tool fleet in customers’ hands. The manufacturer holds me not because I physically cannot put its battery into another drill—I can; adapters exist, safety is the question—but because I have four batteries and two chargers, a tower of cases, and a habit, and all of that gets zeroed out by switching. Switching cost is measured not in volts, but in dozens of purchases spread across years.
Hence my bet, and it can be tested: the death of ’290 opened a window for a high-current lithium “clone” market in the United States—Chinese Chervon and Positec, defendants in 2014, have been making an aggressive American push with their brands over the last two years: Ego for Chervon, Flex and Worx for Positec. And here is what stands out: even they are not going for a cross-brand connector. Each is building its own lock. Because now, with patent restrictions gone, the only defense against downward commoditization—whoever is cheaper wins—is the axis of compatibility, the very thing nobody touched before out of fear of the patent club. You cannot run an A/B test, but the observable picture is this: the patent died—the moats remained. Which means the moats are needed not by technology, but by economics. And while TTI reports 40%+ margins with aftermarket battery sales on the list of drivers, expecting a universal pack makes about as much sense as expecting MLS and MLB to play by the same rules.
The source of the hook is Habr, the article “How DeWalt, Milwaukee, and Hilti Came to Resemble LEGO. And Why Their ‘LEGO’ Is Still Not Compatible with Each Other” (October 28–29, 2026). I independently checked the key facts against primary sources: the text and legal history of US 7,554,290—Google Patents; Milwaukee’s June 30, 2009 press release on the patent grant—the TTI archive; CAFC decision No. 17-1305 of February 16, 2018—the court website; the $27.8 million jury verdict against Snap-on—FOX6 News, October 27, 2017; TTI Annual Results 2023/2024 (the CEO statement and press release with the 40.3% margin and “aftermarket battery sales”); the ITC’s final determination on Klein/MODbox—the Federal Register of October 2, 2026 (Inv. No. 337-TA-1409); arguments against standardization—Power Tool Institute, “Battery Adapters” (2021), and ToolGuyd, “There’s No Universal Cordless Power Tool Battery” (2023).