Bosch Core18V 4.0 Ah Slim Pack Battery News & Opinion

Bosch Core18V 4.0 Ah Slim Pack Battery

We updated our Core18V battery review a few weeks ago with news of a new Bosch Core18V 4.0 Ah Slim Pack. More than just creating a slim pack for Core18V, it’s a genuine step forward for the high-power battery from Bosch.

10-Second Summary

  • Uses 21700 cells instead of 20700 or 18650
  • 1P, 5-cell pack
  • Has a slightly larger footprint, but full compatibility
  • Precursor to a 2P 8.0 Ah pack
  • $99


Bosch Core18V 4.0 Ah Slim Pack Battery20700 cells gave the original Core18V battery 6.3 Ah with its 10-battery configuration (5S2P). The move to 21700 cells offers more energy storage and give the new slim pack 4.0 Ah with just 5 cells. The next move is not far behind with Bosch’s 8.0 Ah 2P pack. Over in Europe, photos are circulating about a 12.0 Ah pack as well.

The slight increase in cell size is also driving a slightly large footprint. Not to worry, they’re still compatible with all Bosch 18V cordless tools.

Price on the new slim pack will be $99 – pretty reasonable when you compare it to other manufacturer’s 4.0 Ah packs.

  • Milwaukee 18V 4.0 XC: $119
  • DeWalt 20V Max 4.0: $119.99 (with Bluetooth) or $148.35 (2-pack)
  • Ridgid 18V 4.0: $89 (2-pack available for $99)
  • Hitachi 18V (No 4.0 Ah available)
    • 3.0 Ah: $39.99
    • 6.0 Ah: $147.41
  • Makita 18V 4.0: $189 (2-pack)

The power advantage from the original Core18V is still there for the slim pack. With the size and weight, the slim pack is going to have the most benefit on smaller tools like drills and impact drivers, so do you really need more power there?


Their current lineup of cordless tools will get the job done. However, performance results in our shootouts show that they’re lagging against the other premium manufacturers. What the Bosch Core18V 4.0 Ah Slim Pack does is give them a power source that they can design more powerful drivers around while keeping the weight and size down in those smaller tools. With that as a foundation, I expect their next generation of cordless tools to compete very well in the space while maintaining Bosch’s excellent build quality and ergonomics.

Bosch Core18V 4.0 Ah Slim Pack Battery

Bosch Core18V 4.0 Ah Slim Pack Specifications

  • Model: Bosch GBA18V40
  • Voltage: 18V
  • Cells: Five 21700
  • Dimensions: 4-9/16″ x 3″ x 1-13/16″
  • Weight: 1.15 pounds
  • Price: $80.65

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Love my Bosch cordless tools but that notorious lag in new releases is how I ended owning pretty much every other battery/tool platform also. Now I can have any tool I think is best, regardless of platform. These new Core batteries are the best thing I’ve seen in a while though. Looking forward to the next generation of tools to attach to them as well.