Shelly H&T – a Year Later

Back in early March 2023 I wrote about the Shelly Door/Window sensor and remarked on it’s use of twin CR123A batteries – I remember commenting about the size of them. At the same time I BRIEFLY mentioned the Shelley H&T – a pretty-looking but otherwise non-descript temperature and humidity sensor. I did nothing with it as I generally use Zigbee sensors around the house.

Today I happened see a phone notification that the Shelly H&T has a low battery – so here goes… the H&T uses a single Lithium CR123 battery, the price of which seems to centre around €2 per battery depending on buying singles or multi-packs.

So, I received the Shelly H&T in March 2023 but I’m looking at my phone which has history for the device from June 2023 until now, possibly coinciding with getting the Samsung S22 Ultra phone around then… can’t be sure. What I can say for sure is that the sensor has sat on my shelf since then working utterly reliably – no problem… and it’s voltage sensor is currently stating 12% remaining – if accurate that suggests it has very little time left to run – at best less than a year battery life (and as you can see, this is an Energizer battery, not cheap rubbish).

So, reliable, kind of good looking but otherwise unremarkable – about the only thing I can say is.. why the relatively expensive CR123 battery? My other sensors use either a single CR3032 or CR2450 and I have several which have outlasted a year. The CR2032 batteries are DIRT CHEAP and while the CR240 last longer while being only a little less expensive than the CR123, they are BOTH a sight smaller than the latter. What made Shelly go for the CR123 for no apparent benefit? Probably due to being WIFI rather than Zigbee operated…

So if battery price and overall sensor height is not an issue and you want a nice little display-less sensor sitting on a shelf – go for it. If you need to leave the device unattended for over a year, this is likely not for you. Looks to me like the device is taking temperature readings once an hour.