@Necessiter thank you. I followed this. Fixed one and improved battery level on another. I have reached out to support via form in the app

  @Sssmmm 

Firmware Version 3.3.951 Build 1287

HTH

  @Mervyn1956 

Are you referring to the KE100 heads firmware? All mine are showing 2.8.0. There isn't any option for a manual firmware upgrade on the app

  @Matthew_Edi 

No not the heads firmware.

That is the hub firmware.

I was sent a link to update it by support on here.

  @Mervyn1956 

Weird... I've been sent that too, but my hubs (KH100) are showing 1.5.23 (no build info)

  @Necessiter 

Hi, many thanks

this worked for me.

I reminded that as I have installed three KE100 devices, the only last of them show low batt error. even after batt changed / both brend new

It is most probably so, because, as I get used to the installation process, this was the first time, I've attached it to the radiator before registration to the HUB.

Registration process to the HUB runs in parallel with the valve calibrating at the same time. High current most probably tweaks voltage value while voltage is measured.

I use rech. Li-ion 1,5V batteries, which should be less sensitive to current reduction. However I got the same error in the end.

removing Thermostat from the app, detaching device from the radiator ... simply Your way works.

Battery voltage is measured obviously while in pairing process. 

While unattached from the valve, voltage deviation is minimum.

Guess definitely firmware issue. 

current FW 2.10.0

//I didn't try to wait a week or so, if another measurement of the batt will occur, but I think that there has to be some measurements scheduled. doing nothing would may fix it as well.

thanks again

I have been testing a set of four valves in one room since March 2025. They taked the temperature from T315. I created a group. Everything worked as it should.
However, I needed to change the user in the app (for personal reasons). The only way to do this was to restart all devices and reconnect them to the app.

To my surprise, before the restart, all valves showed a battery status of 3/4.

After restarting (after 5 minutes) and connecting to the app, the battery status changed dramatically. Some are dead, some are almost dead. I even put in new batteries, but the result was the same. Only the 4th valve shows 4/4, probably because I had to remove it during installation...

Kasa App 3.4.402
Kasa KE100 1.0  Firmware 2.10.0