So, I have some BAT612 18V batteries from Bosch.

I should be able to use both batteries with either of my tools (Angle Grinder - GWS18V-45PC, Drill - DDS181A), but one battery works in both tools and the other only works in the drill.

Does anyone know why this is the case?

Or maybe how to fix it?

  • 2
    Maybe one is tired and the circuitry in the grinder doesn't consider it adequate. The tools are designed to not over-drain LI batteries because that can destroy them.
    – isherwood
    Jun 29, 2021 at 21:10
  • @isherwood OCP/UVP is handled by the battery's charge controller (built into each battery pack), not the tool.
    – dandavis
    Jun 29, 2021 at 22:34
  • You're probably right, but I wonder if it isn't a little of both. My only other idea is a quirky contact issue.
    – isherwood
    Jun 30, 2021 at 12:38
  • Yeah, I could see that the contact issue, but they both are fairly straight and new, but I did notice when I clicked the battery in that doesn't work in the Angle Grinder. I can push the battery check button and everything is OK until i press the tools trigger. Then it cuts off.
    – GregTheHun
    Jun 30, 2021 at 16:42

1 Answer 1


Contact issue, I think. Please see if one tool has a deeper contact than the other. Or rough up the tool contact with some sand paper.

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