DeWalt FLEXVOLT 20V/60V MAX 9Ah Battery (2 Pack)

Starting a job with these packs feels a bit like showing up with a full Jerry can: there’s enough energy on tap to power almost anything in the FlexVolt lineup, and plenty of 20V tools too. I’ve been running a pair of FlexVolt 9Ah batteries for the past year across outdoor equipment, woodworking, and a portable compressor. They’re not dainty—each one is a chunky block—but they’ve become the default power source for anything that’s hungry for watts.

What they are and why they matter

FlexVolt batteries are interesting because they bridge two ecosystems. On a 20V MAX tool, this 9Ah pack acts like a big 9.0Ah battery. On a 60V MAX tool, it reconfigures internally to deliver the higher voltage at a lower amp-hour rating—roughly 3.0Ah—but the total energy stays the same: about 180 watt-hours per pack. That energy density is the story here. For high-draw tools (grinders, circular saws, blowers, string trimmers) and for dual-battery, 120V MAX tools, these feel like the “right size.”

Compatibility has been seamless. The packs click onto my 20V and 60V tools, and they charge on my existing 20V chargers without any drama. The LED fuel gauge is accurate enough to plan your next move—especially useful on outdoor tools where running out 200 feet from the shop is a pain.

Power and runtime in the real world

Across 60V tools, the immediate upside is headroom. The saws don’t bog, the grinder stays alive through heavy pressure, and the leaf blower feels like it’s running near a wall outlet. On a 60V string trimmer, I can clear dense fence lines and edging for roughly 20–30 minutes of mixed throttle per pack. Move to a 60V blower on high and you can drain a pack in well under 20 minutes—less if you’re holding the trigger wide open the whole time. That’s not a weakness of this battery so much as a function of power draw; high cfm and speed come at a cost. If you plan to clean a large yard in one go, run two packs and swap halfway.

Where these shine is heavy cutting. On a 60V circular saw ripping 2x lumber, I can make long, continuous rip cuts without the motor hiccup you feel on smaller packs. Side-by-side with 6Ah or 4Ah options, the 9Ah maintains full power further into the cut and recovers more gracefully after you stall the blade. With the 20V table saw and miter saw, using two batteries in 120V configuration, I can break down a couple dozen studs, crosscut trim, and still have room for clean-up cuts. It’s not an all-day solution for production framing on battery alone, but for punch lists, remote work, or backyard projects, the runtime is legitimately useful.

On a portable compressor, the 9Ah pack is a sweet spot. Seating beads on motorcycle tires and topping off trailer tires feels routine, not a gamble. The pack delivers stable voltage until close to empty, so nailers and tire inflators don’t stutter or misfire as the battery winds down.

Weight, balance, and ergonomics

A single pack weighs about 3.45 pounds. You notice it. On small 20V tools—compact drills, impact drivers—the center of gravity shifts uncomfortably, and the combo becomes more tiring overhead or at arm’s length. On 60V tools, the weight tends to balance better; it’s part of the platform’s heft anyway. My rule: I use these 9Ah packs for 60V gear and for 20V tools that sit on a surface (miter saw, table saw, compressor) or where high draw compensates for the bulk (circular saws, grinders). For compact 20V hand tools, a 5Ah or 6Ah battery keeps the kit nimble.

The case is tough and the pack stands upright reliably, which makes swaps quick. The latch design is solid and the contacts stay clean. After a few drops and some rain, I haven’t had issues with intermittent connections or odd shuts-offs.

Charging and battery management

On DeWalt’s fast chargers, I typically see 60–90 minutes from near empty to full, depending on ambient temperature and the state of the cells. Standard chargers take longer. Two practical tips:

• Don’t run them to absolute zero. Like most lithium-ion packs with a protective battery management system (BMS), deeply discharging and then leaving the pack flat can put it into a low-voltage state that some chargers won’t wake from. When the tool first signals low battery, swap packs. If you accidentally run it all the way down, put it on the charger promptly and let it sit; if it won’t start charging, try a different compatible charger before assuming the worst.
• Store around half charge if the pack won’t be used for a while. That preserves long-term health and reduces the chance you pull a dead pack off the shelf months later.

Thermally, the packs behave well. I’ve used them in cold conditions and didn’t see dramatic voltage sag; you’ll still lose some runtime in sub-freezing temperatures—as you will with any lithium pack—but the tools remained usable. On the other end, if you’ve been ripping or grinding hard, give the pack a few minutes to cool before charging fast. It shortens charge time and is kinder to the cells.

For those wondering about charging compatibility: the pack is backward-compatible with 20V MAX chargers. No charger is included in the two-pack, so plan accordingly if you’re building a kit from scratch.

Durability and long-term use

Tough environments haven’t bothered these batteries. The outer shell resists scuffs and impact, the latch springs haven’t softened, and the fuel gauge remains accurate. After many cycles, my pair still holds a charge well. I monitor performance by listening for early tool cut-outs and tracking how often I need to change packs on routine tasks; the trend line has stayed flat. That speaks to decent thermal management and conservative cell selection inside the pack.

As with any battery, there are ways to shorten its life: leaving it on a high-drain tool that trickles power when “off,” storing completely dead or flaming hot, or fast-charging immediately after a heavy discharge on a hot day. Avoid those, and these packs seem to age gracefully.

Who benefits most

If your 20V kit is mostly drills, drivers, and a random light or two, these are overkill. The weight penalty outweighs the convenience most days. But for 60V tools—mowers, blowers, trimmers, circular saws, grinders—these 9Ah packs are the sweet spot of runtime, power delivery, and versatility. They’re also great on stationary or benchtop 20V tools that can use a bigger reservoir without punishing your wrists.

The two-pack configuration also makes practical sense. One runs while the other charges; on a fast charger, you can keep most jobs moving without a pause.

Value

You pay a premium for high-capacity FlexVolt packs, but the watt-hours per pack, dual-voltage compatibility, and the ability to run 120V MAX tools make them more than a “bigger 20V battery.” If you’re already in the 60V ecosystem or plan to be, this is the capacity tier that minimizes downtime and avoids the need to constantly micromanage charge levels.

Final thoughts and recommendation

The FlexVolt 9Ah batteries are workhorses: lots of energy, stable output, and broad compatibility across 20V and 60V tools. They’re heavy, and they’re not the right choice for every tool. But paired with high-draw gear, they deliver the performance and runtime that make cordless feel truly corded.

I recommend this two-pack to anyone invested in 60V tools or running 120V MAX setups, and to users of 20V benchtop and high-demand tools who want fewer battery swaps. If your kit is primarily compact 20V hand tools, consider smaller packs for balance and weight, and keep one 9Ah on hand for the occasional power-hungry task. Use them thoughtfully—avoid deep empty, store around half when idle—and they’ll make your cordless workflow simpler and more capable.