When using the Wireless Halcyon controller, you'll need some way to power your keyboard. One of those ways is this Coin Cell Battery Board, which puts your wireless controller in an efficient low-voltage mode.

Features

• A dedicated on/off-switch provides a physical means of cutting off power.
• A reset button duplicates the controller's own reset button function, so it will remain accessible while you have the power board installed.
• With a separate left and right side, replacing the battery won't require disassembly: the battery slides out on the side where the keyboard's keys are not.
• Connect the power board using a 6-pin flexible flat cable connector (cable included with the controller bundle).
• While the battery is non-rechargeable, you can still power the board using a USB C cable, bypassing the battery board. No need to worry about turning it off first: the circuitry handles this safely.

Battery life

The battery will last you quite a while: without a module and when using the dongle, we estimate a battery life of roughly 6 to 9 months, though your battery may last longer. Here are some usage examples we measured (with a precision of ±10%):

• No modules: 661.3µA active, 27µA idle, 1.63µA in deep sleep.
• Rotary encoder module (rev2): 733µA active, 47µA idle, 1.64µA in deep sleep.
• E-Paper display module: 700µA active, 43.5µA idle, 1.64µA in deep sleep.
• Cirque Trackpad module: 4400µA while using the trackpad, 767µA active, 111µA idle, 1.64µA in deep sleep.
  

By default, the keyboard will be active while holding a key. It will then immediately enter idle mode after you release the key, and will enter deep sleep after 15 minutes of inactivity. It is possible to manually turn off the keyboard entirely using the on/off-switch, or to enter deep sleep immediately by using the ZMK Soft Off behavior.

You might've noticed that the power draw varies by module. There are some configurations we have not measured: both the TFT LCD Display Module as well as the onboard RGB LEDs will drain enough power to empty your battery within half an hour. We recommend using the Halcyon LiPo Battery Board instead when you want to use these features, as that can easily be recharged.

Usage without a dongle is only recommended when using a non-split keyboard. The central half will have to keep a bluetooth connection open to both the host as well as the peripheral half, greatly increasing battery drain. When using a LiPo battery, we measured 915µA active, 488µA idle and 2.31µA in deep sleep. As the keyboard will spend most of its time in idle mode in use, that'd be an order of magnitude higher use than when using a dongle, and you would measure the lifetime of a battery in weeks instead of months. As that would be a waste of non-rechargeable batteries, we'd recommend using the Halcyon LiPo Battery Board instead when not using a dongle.

In the package

• Two coin cell battery boards: a left side and a right side.
• Included batteries: 1632 form factor, 3V, 130mAh capacity.