No, it is not necessary to fully discharge these batteries before recharging as they do not suffer from so called memory effect.

AA Rechargeable Batteries - NiMH | Battery Logic UK AA Rechargeable Batteries - NiMH | Battery Logic UK

I think this is why Tado doesn't recommend other types of batteries. By observing their "very diligent" documentation style I can imagine that they don't want to recommend inserting fingers or tweezers into the battery compartment in case things go wrong. https://community.tado.com/en-gb/discussion/3099/released-rechargeable-batteries-in-smart-radiator-thermostats-va02-hardware-revision Designed to be used for the regular battery consumers and professionals the Panasonic Eneloop rechargeable batteries are the perfect choice for powering medium to high current consuming devices such as Digital Cameras, torches, game controllers, radio-controlled toys and a range of household devices. The Panasonic Eneloop AA batteries are the latest multi-purpose batteries by Panasonic (formerly Sanyo Eneloop) providing long-life, pre-charged, energy and money saving, eco-friendly rechargeable batteries.apparently the specific type of battery. eg Panasonic eneloop 1900mAh is important. Perhaps tado help are confusing the issue, and it's really about SIZE not TYPE, and its other issues that are causing battery failure. Perhaps it's both. But they need to be clear. These batteries benefit from superior performance even at low temperatures down to -20 ℃ making them suitable for various conditions and occasions. My understanding regarding other brands and capacities is that there is a question mark over physical fit. That would include the 2500 LADDAs, just like the larger Eneloops. So in essence seems to me there are 3 design issues with the radiator thermostat in connection with battery use that I have discovered. Pretty major I think and im mulling getting rid of them

Panasonic Eneloop AA 4ks 3MCCE/4BE od 299 Kč - Heureka.cz Panasonic Eneloop AA 4ks 3MCCE/4BE od 299 Kč - Heureka.cz

Recycle responsibly, a wide range of schemes are available. Most batteries rechargeable or non-rechargeable can be recycled. Also, thinking this hypothesis out loud - What if VERY cheap non-standard battery types tend to heat up (event) at mechanically idle current and thus cause reading error? (I don't think anybody will do that though :) ) These new Panasonic Eneloop AA batteries can be recharged up to 2100 times. These revolutionary low self discharge rechargeable batteries retain 70% of their charge for up to 10 years. The Panasonic Eneloop AA rechargeable batteries are pre-charged using solar energy.Welcome to the brand new Panasonic Eneloop AA rechargeable batteries with improvements in performance and sustainabiltiy. These new Panasonic Eneloop rechargeable AA batteries hold even more energy and have an improved capacity of 2000mAh. This new version has up to 7% more capacity and will perform outstandingly well in demanding situations. They're on the charger now, so far too early to comment on performance in the long term, but I tried two pairs in one of my Tado SRTs and the fit was easy peasy. Also, no problem to operate the SRT with the "ready to use" charge they came with.