zigbee-window-treatment: IKEA blinds report BatteryPercentageRemaining as 0–100, but driver halves it (battery shows ~50%)

[ldeora]

Summary

When using the stock SmartThings zigbee-window-treatment Edge driver, IKEA blinds show a battery percentage that is exactly cut in half (e.g., a freshly charged battery shows ~50% instead of ~100%). Switching to Mariano’s community driver shows the correct battery percentage.

This makes the built-in driver feel “partially supported” for IKEA blinds, even though they are now matched by the stock driver.

Affected devices

• Manufacturer: IKEA of Sweden
• Device: IKEA smart blinds / window treatments (e.g., FYRTUR/KADRILJ/TREDANSEN)

Steps to reproduce

1. Pair an IKEA blind to a SmartThings hub.
2. Assign it to the stock driver: SmartThings / zigbee-window-treatment (default/official driver).
3. Fully charge the IKEA battery pack and reinsert it (or otherwise ensure the blind reports a “full” battery).
4. Check the battery percentage in the SmartThings app.

Actual behavior

Battery is displayed at ~50% when it should be ~100% (i.e., it appears halved).

Expected behavior

Battery is displayed correctly (e.g., ~100% after a full charge).

Analysis / likely root cause

Zigbee PowerConfiguration -> BatteryPercentageRemaining (0x0001 / 0x0021) is commonly interpreted as 0.5% units (0–200), so many handlers divide by 2 to convert to 0–100%.

However, IKEA blinds appear to report BatteryPercentageRemaining already in 1% units (0–100). If the handler divides by 2 anyway, the displayed value becomes half of the real percentage.

The stock driver currently registers default handlers (including Battery) without an IKEA-specific exception:

• Stock driver init.lua: https://github.com/SmartThingsCommunity/SmartThingsEdgeDrivers/tree/main/drivers/SmartThings/zigbee-window-treatment/src

Mariano’s driver fixes this by skipping the divide-by-2 for IKEA:

local function battery_perc_attr_handler(driver, device, value, zb_rx)
  if device:get_manufacturer() ~= "IKEA of Sweden" then
    value.value = math.floor(value.value / 2.0 + 0.5)
  end
  device:emit_event_for_endpoint(zb_rx.address_header.src_endpoint.value,
    capabilities.battery.battery(value.value))
end

Source

Mariano’s IKEA subdriver (reference implementation):

https://github.com/Mariano-Github/Edge-Drivers-Beta/blob/7e27b19016354ecb640e73cc69dc70ea6f71117f/zigbee-window-treatment/src/IKEA/init.lua#L82-L87

Proposed fix

Add IKEA-specific battery handling in the stock zigbee-window-treatment driver, for example:

• Add a small IKEA subdriver that overrides the attribute handler for:
  • PowerConfiguration.attributes.BatteryPercentageRemaining
• For device:get_manufacturer() == "IKEA of Sweden", treat value.value as already 0–100 and do not halve it (still clamp to 0–100).
• Keep the existing/default behavior for other manufacturers/devices.
• Alternative approach: implement a manufacturer/model exception directly in the driver’s battery handling, but a subdriver keeps the logic isolated and consistent with other vendor quirks.

Related discussion

SmartThings Community thread:

• https://community.smartthings.com/t/smartthings-shades-window-treatment-driver-bug/307114

[mocelet]

If it's like in IKEA buttons it gets trickier since starting in firmware 24.x they fixed the bad protocol compliance and report the battery correctly using 200 as 100%. They have to discriminate by firmware version.

Edit: Indeed, same goes for the blinds https://forum.phoscon.de/t/fyrtur-battery-percentage-remaining-166/3842