6Ah Power Tool Battery Comparison: Genuine Milwaukee vs Three Budget Alternatives

Introduction

Power tool batteries have gotten expensive, and it is easy to see the appeal of budget alternatives. A genuine Milwaukee 6.0 battery costs around $90, while several knockoff brands sell packs claiming the same 6 amp hours for $22 to $30 each. Some even claim to match or exceed OEM specifications.

To find out whether the savings are worth the risk, we compared the Milwaukee Red Lithium XC 6.0, an older Milwaukee 5.0 with hundreds of charge cycles behind it, and three budget packs from Labech, Amatike, and Tenmore. Each battery was run through runtime, torque, grinder, and short-circuit tests, then opened up for a look at the cells inside.

How the Batteries Were Tested

Each pack was paired with a Milwaukee 175 watt power supply setup and used to power a fan drawing roughly 150 watts, with streamers attached so the moment of shutdown was visible. All packs were freshly charged before every test, and each brand was tested three times in the torque and speed trials for consistency.

Every battery in the comparison claims 6 amp hours, which should work out to about 108 watt hours across ten cells. As you will see, not all of them deliver.

Runtime Results: The Fan Test

The Labech, fully charged at 20.9 volts, started at 138 watts and lasted 25 minutes and 20 seconds, ending at 15.2 volts. The Amatike, the lightest pack at 596 g, disappointed at just 15 minutes and 50 seconds, roughly ten minutes less than the Labech. The Tenmore managed 21 minutes and 44 seconds, about four minutes short of the Labech.

The genuine Milwaukee Red Lithium XC 6.0, which claims 50% more power and cooler running, kept going strong past 23 minutes and finished at 39 minutes and 15 seconds, over ten minutes ahead of everything else.

The real surprise was the five-year-old Milwaukee 5.0, weighed down by hundreds of charge and discharge cycles: it still lasted 28 minutes and 40 seconds, beating all three knockoff brands by more than three minutes despite being a smaller capacity pack.

Torque and Speed Under Load

Using a Milwaukee drill in second gear driving 5-inch lag bolts, the 6.0 Milwaukee delivered 183 in-lb, the best result. The old 5.0 Milwaukee came close at 175 in-lb. Of the budget packs, the Tenmore reached 146 in-lb and the Labech 143 in-lb, while the Amatike could not feed the drill enough current and gave up at only 89 in-lb.

With an impact driver, which draws far less current, the gap narrowed. The Labech averaged 6.31 seconds per bolt, the best of the knockoffs. The 6.0 Milwaukee averaged 6.00 seconds, just edging out the 5.0 Milwaukee at 6.08 seconds. The Tenmore averaged 6.95 seconds and the Amatike struggled again at 7.15 seconds.

The Angle Grinder Torture Test

This is where budget packs fell apart. A heavily loaded angle grinder is thirsty, and the results separated the well-designed packs from the dangerous ones.

The Labech gave up at 1 minute 52 seconds. The Amatike died in only 10 seconds and could not be restarted. The Tenmore lasted 3 minutes 33 seconds, but with no overload protection claimed, the battery overheated and started smoking, and its voltage dropped to just over 2 volts, deep into lithium damage territory. The Milwaukee charger refused to charge it afterwards, flashing error lights.

The 5.0 Milwaukee finished in 2 minutes 42 seconds without smoking, and the 6.0 Milwaukee ran an outstanding 6 minutes 38 seconds, roughly twice as long as the second-place finisher.

Short-Circuit Safety Testing

Shorting each pack through a current meter revealed serious differences. The Labech, which claims short-circuit protection, hit 112 amps and cut power almost immediately, with only a small amount of smoke. Its thin metal interconnect melted like a fuse as designed, so it arguably passed.

The Tenmore reached 227 amps and shut down in under 2 seconds, with its interconnect also acting as a fuse. Better, but not clean.

The Amatike hit 123 amps and took almost 8 seconds for the current to drop to zero, smoking badly the whole time and coming dangerously close to catching fire. Some of its cells began melting and leaking. This is not a battery you want in your shop or home.

The Milwaukee reached 390 amps but shut down in about 2.5 seconds before things got out of control, with its fuse-style interconnect working exactly as designed.

Inside the Packs: Cell Quality and Capacity

The three knockoff brands use ten 18650 cells each, while the Milwaukee uses ten larger 21700 cells, one reason the genuine pack weighs 1,077 g versus 651 g (Labech), 596 g (Amatike), and 663 g (Tenmore).

Internal resistance told a similar story: 12.9 milliohms for the Labech, 13.4 for the Amatike, 13.1 for the Tenmore, and just 5.9 for the Milwaukee.

Discharged at a gentle 1 amp, the real capacities emerged. The Labech delivered 2,822 mAh, the Tenmore 2,841 mAh, and the Amatike a terrible 1,520 mAh. The Milwaukee delivered over 1,000 mAh more than its closest competitor. Working the math on claimed watt hours, the Labech actually provides about 75 Wh, the Tenmore 73.5 Wh, the Amatike just 54.7 Wh, and the Milwaukee 113 Wh. So yes, the budget packs fall well short of their advertised 6 amp hours.

Buying Advice

The philosophy of “buy once, cry once” holds up here. If you rely on your tools daily, the Milwaukee Red Lithium XC 6.0 is the clear winner on runtime, power delivery, and safety, and even the five-year-old Milwaukee 5.0 outperformed every budget pack tested.

That said, there are moments when a knockoff makes sense. At around $22 per pack, the Labech is the only budget battery that passed the short-circuit test reasonably well and delivered acceptable, if overstated, capacity. Treat it as a light-duty spare, not a daily driver, and avoid the Amatike entirely.

Conclusion

The genuine Milwaukee 6.0 beat every other battery in every meaningful test, and even a well-used Milwaukee 5.0 outlasted all three knockoffs. If safety and longevity matter to you, the premium is justified. If you just need a cheap backup pack for occasional light use, the Labech is the least risky budget option, while the Amatike is best left alone.