Professional cordless power tool users have watched battery performance climb steadily over the past decade. Higher voltage packs, multiple battery configurations, and larger lithium-ion cells each offered different paths to more power and longer run times. Understanding how these approaches compare helps contractors make informed decisions about which platform best suits their specific work needs on the job site.
The cordless tool market reached a critical point where standard 18V systems could no longer meet the power demands of larger stationary equipment and heavy-duty cutting tools. Manufacturers responded with three distinct engineering strategies, each carrying different trade-offs in cost, weight, compatibility, and real-world performance. Some brands pushed operating voltage higher. Others designed tools to accept two or more battery packs simultaneously. Many adopted larger lithium-ion cell formats that delivered more energy per cell. Each strategy solved the same core problem, but implementation details mattered greatly for end users choosing a long-term platform.
Three Strategic Paths to Higher Power
As tool makers looked beyond the limits of existing 18V systems, three approaches emerged in the 2016-2018 period. Some brands pushed voltage higher by introducing 36V, 40V, and 60V platforms. Others kept the same nominal voltage but wired two battery packs together inside the tool for more power. A third group invested in larger battery cell formats, moving from the standard 18650 cell to 20700 and 21700 sizes that delivered more capacity without requiring voltage changes.
Voltage Scaling Strategy
Raising system voltage is the most direct way to increase power output. Power equals voltage multiplied by current drawn, so doubling the voltage doubles the theoretical power available at the same current. DeWalt introduced FlexVolt technology in 2016, allowing a single battery pack to deliver 20V Max on existing tools or reconfigure its cells to deliver 60V Max on compatible tools. Bosch and Hitachi (now Metabo HPT) pursued 36V platforms for specific tool categories like miter saws and rotary hammers. The trade-off was that higher-voltage tools often required larger, heavier battery packs and could not accept standard 18V batteries without platform-specific adapters or redesigns.
The 36V and 60V Design Approaches
A 36V system typically uses two 18V battery packs in series, either housed in a single enclosure or as separate packs mounted side by side. A 60V system like FlexVolt uses a single battery with cells reconfigured internally to deliver the higher voltage when the tool demands it. Both approaches deliver more power, but they differ in battery compatibility, weight distribution, and the range of tools that can take advantage of the higher voltage. A 60V table saw draws current from a single pack, while a 36V miter saw requires two packs, doubling the total energy available for extended cutting through engineered lumber and dense hardwoods.
Higher Voltage Systems in Practice
Several major brands committed to higher voltage platforms as a long-term strategy. DeWalt’s FlexVolt line allowed 20V Max tools to run on the same battery that powered 60V Max and 120V Max tools. Makita took a different direction with its 40V Max XGT platform, an entirely new system incompatible with its existing 18V LXT line. Each approach carried implications for tool tracking and fleet management on larger job sites where multiple battery platforms were already in rotation across different crews and trades.
Platform-Specific Trade-Offs
Backward compatibility became a major concern for contractors with existing tool inventories. FlexVolt batteries worked with existing 20V Max tools, providing longer run time even when those tools could not access the higher voltage. XGT batteries required new tools entirely but delivered higher sustained power output for heavy applications like demolition hammers and large angle grinders. Milwaukee remained at 18V while pushing the limits of what its M18 platform could deliver through advanced motor electronics, smarter battery management systems, and larger cell formats. Each manufacturer bet on a different balance of compatibility, power output, and future expansion potential.
| Approach | Example System | Voltage | Backward Compatible | Primary Benefit |
|---|---|---|---|---|
| Higher Voltage | FlexVolt | 20V/60V/120V | Yes (20V tools) | Single battery across platforms |
| Higher Voltage | XGT | 40V | No | Full sustained output at 40V |
| Dual Battery | 18V x2 | 36V effective | Yes (same packs) | Uses existing battery inventory |
| Large Cell | High-capacity packs | 18V | Yes | Longer run time at same voltage |
The decision between these approaches depended heavily on the type of work being done. A framing crew running miter saws and table saws all day might benefit more from higher voltage or dual-battery systems that deliver sustained cutting power. A crew doing all-day drilling and fastening might prefer large-cell packs that maximize run time without requiring charger upgrades or new tool purchases. Fleet managers needed to evaluate not just tool performance but the total cost of transitioning or maintaining multiple battery platforms across the organization.
Multi-Battery Configurations for Heavy Equipment
Using two or more battery packs simultaneously gave manufacturers a way to power larger tools without requiring an entirely new battery platform. Makita’s 18V X2 line used two 18V batteries in series to deliver 36V power for miter saws, circular saws, and rotary hammers. Festool offered an 18V x 2 cordless plunge-cut circular saw for sheet goods and panel work. DeWalt introduced a 20V Max x 2 mower for large lawns and commercial landscaping. This approach allowed users to tap into batteries they already owned rather than investing in a completely separate battery ecosystem for heavy equipment.
Series vs Parallel Configurations
Wiring two battery packs in series doubles the voltage while keeping the amp-hour rating the same. Wiring them in parallel keeps voltage constant but doubles the available run time. Most dual-battery tools use series configurations for higher power delivery. A miter saw running two 18V 5.0Ah packs in series delivers 36V with 5.0Ah total capacity, enough for hundreds of cuts in pressure-treated lumber and engineered beams. Some tools switch between series and parallel depending on the operating mode selected, offering both high power and extended run time from the same two packs depending on the task at hand.
Job-Site Examples Where Dual Batteries Matter
Portable table saws, large miter saws, and cutoff machines benefit most from dual-battery configurations. A 10-inch table saw drawing 2500 watts or more during heavy ripping would drain a single 18V 5.0Ah pack in under four minutes of continuous cutting. Two packs in series provide a practical run time while delivering the cutting torque needed for ripping dimensional lumber and sheet goods. These tools fill a gap between compact cordless job-site saws designed for trim work and full-size corded equipment, giving crews cordless freedom on jobs where power is not yet run or where extension cords create trip hazards and productivity bottlenecks.
The Shift to Larger Battery Cells
While voltage and multi-pack strategies drew attention at media events and trade shows, battery cell technology underwent a quieter but equally important transformation. The standard 18650 lithium-ion cell had been the workhorse of cordless tool batteries for over a decade. Manufacturers began moving to larger form factors, 20700 cells (20mm diameter) and 21700 cells (21mm diameter), which offered higher capacity and better power delivery characteristics. This shift allowed brands to evolve their existing battery platforms without changing voltage or tool compatibility.
18650 vs 20700 vs 21700 Performance
The larger cells bring several measurable advantages in capacity, discharge rate, and thermal management. A standard 18650 cell tops out around 3.0Ah to 3.5Ah with moderate continuous current ratings between 15A and 25A. A 21700 cell can deliver 4.0Ah to 5.0Ah while supporting 30A or more continuous discharge. This means a ten-cell 21700 pack can deliver 40Ah to 50Ah capacity compared to 30Ah to 35Ah from the same number of 18650 cells, all while handling higher peak current loads without overheating. The trade-off is physical size and weight, since 21700-based packs are noticeably larger and heavier at the same cell count.
| Cell Type | Diameter | Length | Typical Capacity | Continuous Discharge | Common Application |
|---|---|---|---|---|---|
| 18650 | 18mm | 65mm | 2.0 – 3.5Ah | 15 – 25A | Compact tool packs |
| 20700 | 20mm | 70mm | 3.0 – 4.0Ah | 25 – 35A | Mid-size and high-capacity packs |
| 21700 | 21mm | 70mm | 4.0 – 5.0Ah | 30 – 45A | HD and high-output packs |
Practical Benefits for Cordless Tools
Higher-capacity cells translate directly to longer run times between charges and better sustained power delivery. A 12.0Ah pack built with 21700 cells can run a cordless circular saw through two to three times more material than a standard 5.0Ah pack before needing a recharge. The higher discharge rate also means tools maintain peak power for longer before voltage sag sets in. For users running demanding tools like angle grinders, core drills, or demolition reciprocating saws, the difference in sustained cutting and drilling performance is immediately noticeable in both speed and consistency.
Planning for Battery Compatibility
Contractors with existing tool investments faced a central question when evaluating new battery technologies: would new packs work with old tools, and would new tools accept old packs? Some manufacturers committed to full backward compatibility. Tool innovations in the 2016-2018 period increasingly depended on the electronics inside both the tool and the battery to manage power delivery, temperature regulation, and cell balancing during charge and discharge cycles. These smart battery management systems required compatible firmware and communication protocols between the tool and the pack, meaning not every older tool could take full advantage of new battery capabilities.
Charger Infrastructure Upgrades
Larger battery packs demand faster, more capable chargers to keep the workflow moving. A standard 30-minute charger designed for 2.0Ah and 3.0Ah packs may take two hours or more to fully recharge a 12.0Ah pack. Multi-port rapid chargers became essential for crews running multiple high-capacity packs through a single workday. A four-port rapid charger can replenish four 12.0Ah packs in about two hours, keeping production moving on larger job sites where downtime for charging directly impacts labor costs and project schedules. Contractors needed to factor charger capacity into purchasing decisions, not just pack voltage and amp-hour ratings.
Battery technology in cordless power tools continues to advance with each product generation. Cell chemistry improvements, more sophisticated battery management systems, and higher energy densities appear regularly in new releases. Tools that once required a cord or a gas engine now operate cordlessly with performance matching or exceeding their corded predecessors. A cordless jigsaw today cuts curves and patterns in hardwood with the same precision and speed as a corded model, thanks to the power delivery and run time enabled by modern battery systems. The three engineering approaches gave manufacturers and users more options than ever before, each suited to different tool categories, budget constraints, and daily work patterns on construction sites.