How to check Windows Mixed Reality motion controller battery level

[Windows Central]

The motion controllers for Windows Mixed Reality headsets run on AA batteries. But how do you know how much power is left? We have the answer.
The fact that you don't have to recharge the motion controllers with your Mixed Reality headset is a blessing, assuming you have a stash of AA batteries at hand. Hot swapping means you don't have to come back to reality and wait for batteries to recharge before you continue your virtual experience.
But the controllers don't have battery level indicators on them, and there's no obvious sign of power levels when you're inside Mixed Reality either ... or is there? In fact, there is. You just have to know where to look.
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