Alkaline vs Lithium

I’ve had the Tado system since 2018 and during that time I obtain around 12 months from Duracell industrial or Procell etc. Recently I thought I would try Energizer Lithium as they seem to provide a steady voltage and are supposed to outperform the equivalent alkaline cell. I have been monitoring dates, location and manufacturer when the new batteries are fitted so that I know roughly when replacements are due so I was expecting longer than 12 months from the lithium. Unfortunately, this is not the case and the smart radiator valves that I have fitted lithium in are showing low battery after only 6 months. Also the voltage drop off is more severe that alkaline and once the low battery notification is announced, the device goes offline quite quickly, unlike alkaline that can last a few weeks. The lithium are 5 times more expensive and in this application last half as long. I know this is hardly a lab standard test but I’m a bit disappointed with my findings. Do the lithium characteristics suit the smart radiator valve application? Is the voltage monitoring correct for the different cell resistance? Does the SRV firmware need updating for lithium?


  • rafm5
    rafm5 | Moderator

    The voltage performance of alkaline batteries when compared to lithium and rechargeable batteries are very different. I believe that although lithium batteries last longer, their voltage drops drastically at the end of their useful life compared to alkaline. This therefore will push many manufacturers against lithium in their devices.

    What type of batteries should I use in my tado° devices?

  • Lithium batteries are not suited to low power devices - under light loads the discharge rate is no better than alkaline. Changing the TRV firmware is unlikely to have any affect, as the issue is with the battery chemistry and how it performs under different loads.