Cordless tool batteries look similar between generations, but the cells inside keep improving. The newest step is the tabless cell, a design that replaces the thin metal strips connecting each electrode to the terminal with a structure that lets the entire top and bottom of the cell carry current. Battery care habits still matter, and the old advice about draining battery packs before charging has been replaced by a better understanding of how modern packs behave.
The first 18V tabless packs, built around 21700 lithium-ion cells, promise longer runtime, higher sustained power, and longer service life than the packs they replace. One announced 8Ah pack claims up to 71 percent longer runtime than the previous 8Ah version at the same voltage, with the same maximum current and power ratings. Understanding what changed inside the cell explains how those gains happen and what they mean for tool buyers.
How Tabless Cell Construction Works
Inside a conventional cylindrical cell, the anode and cathode wind into a spiral, and thin metal tabs connect each end of that spiral to the battery terminal. Current has to squeeze through those few connection points, and every squeeze point adds resistance. A tabless cell removes the tabs: the full face of each electrode becomes the connection, giving current far more pathways to travel.
What Changes With More Current Paths
- Lower internal resistance inside each cell.
- Less voltage drop when a tool draws hard.
- Less heat generated during high discharge.
- More sustained power output at the tool.
The practical result is a pack that holds its voltage longer when a tool demands maximum power. How battery systems evolve across voltage transitions and connector changes shapes what each new cell generation can deliver to the motor.
Building tabless cells requires new welding and assembly lines, which is why manufacturers phase them in model by model rather than replacing every pack at once. For tool buyers, the switch shows up first in flagship batteries and then filters down to smaller packs as production scales, which means the newest cell technology often arrives in the most expensive packs first.
The cells also run cooler under load, which matters for tools that sit in enclosed battery bays on saws and grinders. Heat that never builds up does not need to be vented, so the pack casing can stay simpler and the cells spend more of their life at a healthy temperature.
What 18V and 20V Labels Really Mean
Voltage labels confuse buyers more than any other battery spec. An 18V battery and a 20V Max battery often contain the same cells, and the explanation of when an 18V battery is a 20V battery comes down to nominal versus measured voltage. The cell chemistry is the same lithium-ion either way.
The 21700 designation refers to cell size: 21 millimeters in diameter and 70 millimeters long. The larger format holds more capacity than the older 18650 cells, 18 by 65 millimeters, used in earlier generations. That is how an 8Ah pack fits in roughly the footprint of older 4Ah and 5Ah packs while doubling capacity.
Amp-hours describe capacity, not power. A 4Ah pack delivers 4 amps for an hour in theory, or 8 amps for 30 minutes. At 90 amps of demand, that same pack empties in under three minutes, which is why high-output tools need high-capacity packs or a fast rotation.
Reading the Specs: Current, Power, and Runtime
Three numbers define how a battery performs: current, power, and runtime. A high-output 18V pack typically delivers around 90 amps of maximum current and roughly 1500 watts of maximum power. Tabless cells do not necessarily raise those peaks, but they let the pack sustain them longer, because less of the stored energy is lost to heat inside the cell.
The Runtime Claim
Manufacturers quote the gain in a single number: a tabless 8Ah pack delivering up to 71 percent longer runtime than the previous 8Ah pack. The gain comes from efficiency, not extra capacity. Lower resistance means more energy reaches the motor instead of turning into heat.
Verify the runtime claim before paying the premium. The 71 percent figure comes from a specific test cycle, and your results depend on the tool, the material, and the pack’s state of charge. A practical check is to run the same cut with the old and new packs and time the difference, then decide whether the gain matches the price.
What Longer Lifetime Means
Lower operating temperature extends cycle life. Heat is the main enemy of lithium-ion cells, so a pack that runs cooler should survive more charge cycles before its capacity fades. For anyone replacing batteries every two or three years, that changes the replacement math.
| Property | Tabbed cell | Tabless cell |
|---|---|---|
| Current connection | Thin metal tabs at each end | Full electrode faces |
| Internal resistance | Higher | Lower |
| Voltage drop under load | Noticeable | Reduced |
| Heat at high load | Higher | Lower |
| Sustained high power | Drops as pack heats | Holds longer |
| Runtime in one 8Ah comparison | Baseline | Up to 71% longer |
The battery management system governs how the pack charges, balances cells, and protects against overcurrent and overtemperature, and battery management systems matter more as capacity grows.
What High-Capacity Packs Change on the Jobsite
Bigger packs change more than runtime. An 8Ah pack roughly doubles the work time of a 4Ah pack at the same voltage, but it also adds weight, so saws and grinders feel different in the hands. Charging logistics change too: a drained 8Ah pack takes longer to refill than two 4Ah packs charged in rotation.
On a full workday, pack capacity shapes the whole routine. Crews running high-amperage tools all day plan around battery rotation, and a 15Ah cordless battery changes the calculation toward fewer, heavier packs.
Matching Packs to Tools
- Small tools such as drivers and lights: 2Ah to 4Ah keeps weight down.
- Medium tools such as circular and reciprocating saws: 5Ah to 8Ah balances weight and runtime.
- Heavy tools such as grinders and demo hammers: 8Ah and up for sustained power.
A Rotation That Keeps the Day Moving
- Charge every pack overnight so the day starts full.
- Label packs with a marker and rotate them evenly to balance wear.
- Swap at the first sign of slowdown, not after the tool stops.
- Keep a charger and a spare pack at the truck for midday refills.
Weight matters most on tools held overhead. A grinder with a 4Ah pack balances differently than one with a 12Ah brick, and fatigue shows up by the end of a ceiling job. For overhead work, run the smallest pack that completes the task, and save the big packs for tools that sit on the material, like saws and demo hammers.
Charging speed becomes part of the math as packs grow. A fast charger can refill a high-capacity pack in about an hour, but two medium packs charged in sequence can keep a single tool running all day with no dead time. Many crews prefer that setup over one giant pack, because a pack on the charger is working even when it is not in a tool.
One Battery, Many Tools: Platform Compatibility
A battery is only useful if it fits the tools you own. Most major brands design one battery platform to serve dozens of tools, from drills to lights, and the one battery, many tools idea is what makes a platform worth committing to.
Compatibility also runs backward. New batteries usually work in old tools, and old batteries work in new tools, as long as the voltage class matches. That backward compatibility is why upgrading the cells, as with tabless packs, benefits the whole fleet at once instead of forcing a tool-by-tool transition.
Storage and care still set the floor on pack life. Keep packs in a dry, moderate-temperature place, avoid leaving them fully drained for weeks, and use the charger designed for the pack. A good pack kept in poor conditions underperforms a mediocre pack kept well.
Shared Battery Systems and Buying Strategy
Some platforms go further and let packs cross brand boundaries. AmpShare, for example, lets compatible batteries from several brands power tools in a shared system, and shared battery systems change how buyers weigh brand loyalty against tool performance.
A practical upgrade path starts with three checks. Confirm the new pack fits your existing tools and charger. Compare the runtime gain against the price premium. Weigh a single large pack against two medium packs for charging flexibility. Tabless cells are a real step forward in how long a pack runs and how long it lasts, and the buying decision comes down to matching that gain to your tools, your workday, and your budget.