[Released] Rrechargeable batteries in Smart Radiator Thermostats VA02 hardware revision



  • @ceeceedee Good points on firmware, note I know that different generations of SRTs have different firmware versions and numbers so just wanted to add this for completeness. It has been suggested few years ago that if device has latest firmware it was displayed in say green and that if a new version was available it would be in red. I believed it was going to be implemented but not sure it got dropped. Even a page of latest firmware versions would be useful.

  • Another vote on this.

    Only supporting alkaline batteries on 2020 makes no sense.

  • Vote Up!
    I change everything to rechargeable batteries,.. and now for Tado I am back on old style.
  • Also adding on to the pile. An official answer from Tado about the status might be appreciated!
  • Is there any update yet?

  • AndyMarden
    edited December 2020
    The problem with Ni-Mh rechargeable batteries is the charge, it seems, which might only go as high as 1.2v. What about Lih-Ion rechargeables. They have started to make these at AA size that run at a steady 1.5v throughout use and they have a whopping 3300mah capacity. That would seem to do the trick.

    What I am not clear on, however, is how the device knows that the battery is getting low.

    I am in the process of installing and, of course, awaiting on tado support to do the most basic of config (when will they realise that providing the end user with this will significantly increase satisfaction and reduce the time they have to spend - but I digress).

    Once I have got this set up with the supplied batteries (in about a week I guess, I will try with one trv on these and see what happens, unless anyone had already tried and knows it won't work.
  • really disappointed... +1

  • Go green, allow rechargeables

  • This would seem like such a simple thing to implemented. Allow the user to flick a switch to indicate what type of batteries they use and then apply a different "low battery" threshold.

  • Yes agreed, rechargeable batteries have very little voltage drop they generally just run out. However they can count the number of activation's and flag for recharge after so many. Mine so far have always lasted throughout the heating season UK and I recharge them all over the summer. Others may vary etc and depends on how many devices/rooms people have.

  • What? Doesn’t work with rechargeable batteries? This is a huge deal breaker to me!
  • Ok cmon already, first this:

    Someone mentioned that problem with above ^ issue disappeared after changing to all new batteries. Tado is totally quiet on that issue for 1 whole year.

    Today I bought 26 AA Eneloop batteries and 15 AAA Eneloop batteries (13 SRT and 5 ST) and then I find out about this whole rechargeable issue once I saw battery warnings. I actually bought 32 AA and 24 AAA because of the 8 pieces in package. I was thinking "ok, I'll always have replacement ready and can use spares for other devices in my house". Spent 150 EUR just on batteries because I am thinking long term with this. Another disappointment.

    Literally 2 days ago a friend of mine asked me which thermostat would I recommend for him so that he can turn on/off heating from 'outside' and I fired with no thinking Tado even though I have another issue with Tado SRT in the issue I linked which I have 0 support from Tado.

    It was too expensive for him and I was persuading him why he should go Tado anyways. Today I recommended him a cheaper Becko thermostat, first time hearing about them but they where one of the first search results on Amazon.de.

    Tado you are loosing free marketing and will soon start loosing existing customers.

    This picture had a whole different feel few hours ago:

  • vale4674
    edited December 2020

    Ok cmon Tado, first this:


    Tado is quiet for whole year about the issue ^ above.

    Someone mentioned that changing all new batteries fixed that issue with thermostats (SRT) constantly turning off/on. I gave it a try and also was thinking about Eneloop batteries for my thermostats even before so that I have them for a lifetime basically in my thermostats. 

    So today I bought 32 AA Eneloop and 24 AAA Eneloop batteries. 150 EUR but was thinking longterm.

    I actually need 26 AA and 15 AAA for 13 SRT and 5 ST but was thinking that spares would be for other devices in house and would always have ready charged batteries in case those in thermostats get low. And boy did they get low.

    Disappointment arrived once I replaced batteries in all thermostats and saw battery warnings on almost all of them. Then I found about this rechargeable issue.

    Literally 2 days ago a friend of mine asked me which thermostat would I recommend so that he can turn on/off heating from 'outside'. Without hesitating I said TADO even though at that moment I already had this above linked issue on which I am getting no response. It was too expensive to him and I was still persuading him why he should go Tado. I even offered him to donate him money for the difference in price he is willing to pay, I wanted him to buy Tado Smart Thermostat + Internet Bridge. Yes, I liked Tado that much.

    Today, after this 'rechargeable issue' I recommended him Becko. Never heard about them, it was one of the first searches in Amazon.de and had the features he needs.

    Tado you are loosing free marketing and will soon start loosing existing customers.

    This photo had a totally different feel few hours ago when courier delivered it to my address:

  • This might be implemented in 2025 at the current speed.

  • I totally agree with all comments here

    This has been an issues for many years now (!!) and Tado response is a walk of silence!

    Come on Tado!
    If this is super difficult to fix; just say so!

    It feels like you are hiding and hope this will go way by itself..:)
  • Another urgent vote for rechargeable batteries. Our house isn't super well insulated and about a 100yrs old so temperatures drop quickly which means tado heads need to work all day on and off to maintain temp.

    That means we have to replace batteries 2x a year! Expensive and bad for the environment.

    Tado please allow asap for rechargeable batteries with lower voltage.

    Mine our Duracell HR6/NiMH 1.2v/1300mAh
  • I’m pretty sure Tado will never try and update for rechargeable batteries. The discharge curve for an NiMh cell is almost a right angle, a fully charged cell once settled after charging is 1.25 to 1.3 volts, the instant a load is applied this will drop to 1.2v and will sit there for almost the entire discharge time of the cell, at empty this will drop to about 0.9v, this transition will happen in a very short period of time. This exact issue is the reason they don’t use them as software updates etc would crash or valves would cease to function in open or closed states. I’m not saying I agree with it, it’s just a fact.

  • On a side note, a Li-Ion battery with a micro usb connector on the thermostat so you could charge it back up with your portable 10000mAH phone charger battery pack would have been a great idea, just go to the unit saying low bat and plug it in for a few hours !

  • samd
    samd ✭✭✭

    @Dave21w If that is the case (and I'm not doubting you) why has tado not come clean about this issue?

  • I'd guess as there is alot of people who are pretty miffed about this they are hoping it will go away if they keep quiet, where as I believe if they actually came up with a plausable reason (like my version) people may back off. I do think not having the valve rechargeable is a bit short sighted in the first place. A single Li-Ion (or polymer) cell using the same volume space as 2 AA batteries would have a similar mAh rating and so the run time would be the same, given that a single Li-Ion cell has a charged terminal voltage of 4.2v a low batt point of 3.6v and usually a cut off point of 3.0v this would have been an ideal solution. Your average Alkaline AA is about 2500 mAh so you need to be looking att his sort of capacity if you want some reasonable battery life.

    Further up this thread a guy called AndyMarden (posted 6th Dec) has quoted AA Li-Ion recharables as beeing 3000 mAh, I'm fairly sure he has misread the advert as they say 3000 mWa, this equates to about 800 mAh and you don't get a low batt warning, they just cut off completely.

    I have a couple of spare Tado TRV heads so I may do some current consumtion tests as I believe at the moment if you really want a rechargeable solution the only option is a single LiFePO4 cell, these are AA sized with a fully charged voltage of about 3.2V, you would then need to put a dummy cell (shorted end to end) where the second battery should be, obviously a suitable charger tfor these is also required but I think we talking about a third of the run time - do we really want to be changing batteries every six weeks?

    Please note the above comments are not recommendations, I take no responsibilty for any damage you cause if you attempt any of the above.

  • samd
    samd ✭✭✭

    @Dave21w Please keep us posted - interested in your findings.

  • Strange 2021 and we have still have to use normal batteries!

    And they advice even premium batteries.

    I understand if they change the values a normal battery is not accurate anymore when it drain down.

    But maybe an option to choice in the app or in my tado (where there are more options than the app) if you use normal of rechargeable batteries.
  • I also have observed that my radiator valves when on the latest firmware version do not give me low battery alarms with fully charged rechargeable batteries. Maybe they tried to introduce this feature and had issues.

    I'm still using rechargeables and just make a reminder to recharge them all every 6 months or so.

    I would be more than happy not to have the low battery alarm and instead have a "offline" type alarm when a trv stopped working.
  • So a quick update as promised.

    Looks like “low batt” detection point is about 2.3 volts, very close to the 2.4v of a fully charged pair of NiMh cells so maybe they have tried to tweak the system a little. I’m a bit disappointed that the battery level detection icon does not show a declining voltage but goes from OK to your screwed in one single change.

    Now regarding “different choices” for power, I ran a thermostat up to 3.7 volts without issue, above that it started to whistle so I’m guessing they have a super low current switching power supply in there that doesn’t like too many volts up it. It didn’t damage it and still works fine so for me if my thermostat heads start eating batteries too often I’m going to 3D print a dummy battery module and feed it from an external 18650 cell with a 2amp diode in series with it, at full volts the 4.2 of the cell will loose 0.7v across the diode so the thermostat will get about 3.6v, it will happily run at that until low battery detection at 2.3v at which point the lithium cell will be 0.7v higher which will be 3v, the correct low battery point for the cell. When measuring the maximum current consumption of the thermostat which was during the closing of the valve it peaked at about 330mAh so picking an 18650 cell with a low C rate gets you a higher Ah rating, this means a 3.5Ah cell should give you close to double the run time of the AA’s. I will update again if I end up doing this in the mean time I’ll see how long my Alkaline’s last.

  • Another vote for this.
    Now can Tado weigh in and give this thread an update please?
    Imagine all the single-use batteries that could be saved!
  • I have to say, I'm probably more disappointed with Tado's lack of any response than I am with this lack of obvious feature.

    The latter suggests a company with poor engineering / design choices, which happens to all of them (eg Apple antennagate). The former suggests a company that just doesn't care to engage or respond to its customers......

    Questions and comments seem perfectly reasonable and the community is happy to brainstorm ideas it appears, just the company doesn't care enough to even respond in over a year.

    Hugely disappointing...hope Tado up their game.
  • Hey, given Tado support is nonexistent, was wondering about batteries like this - would these work better than metal hydride batteries?

    These seem to run at 1.5v, so hopefully would avoid the low battery warning of 1.2v ones??

    Just a thought
  • Just changed from another brand to Tado and was surprised reading so many having issues with rechargeable batteries. I bought rechargeable batteries named “KENTLI AA 1.5V 3000mWh” on AliExpress and haven’t had any issues whatsoever with my thermostats.
  • samd
    samd ✭✭✭

    @Dave21w Yes I noticed it yesterday. How do you know if you have VA01 or 02?

Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!