Evohome Controller Battery Issue

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  • seanbts
    Automated Home Lurker
    • May 2017
    • 5

    Evohome Controller Battery Issue

    Hi,

    The EVOHOME controller shows full battery while on charge but if we remove it from the stand, the battery symbol drops to half way and within 4 or 5 minutes, the unit beeps to say batteries are dead and put it back on the stand. Any ideas if there's a fix for this?

    Thanks.
  • G4RHL
    Automated Home Legend
    • Jan 2015
    • 1580

    #2
    This has cropped up elsewhere in these pages. Take the Panel off its charger. Let it run down flat. Take the batteries out. Use the opportunity to make sure when the batteries go back in that they sit tight as it seems with a lot of the Evohome stuff the contacts do not always hold the batteries snug. Put the batteries back and put the Panel back on its charger. Do this every few months.

    Comment

    • DBMandrake
      Automated Home Legend
      • Sep 2014
      • 2361

      #4
      Mine is currently doing this again, for about the 4th time since I've owned it - on the dock it says fully charged and there is no charging symbol, if I remove it from the dock it says it is only half charged, returning it to the dock it says fully charged and no charging symbol again.

      It's not actually necessarily to run the battery down to fix this, the quicker workaround is to remove it from the dock and remove a battery, then put it back on the dock without a battery, let it boot up and wait until the cross appears through the battery symbol (to indicate faulty or missing battery) then insert the battery. It should then start charging, once it does make sure it remains on the dock until fully charged, which will be many hours as the charging is very slow.

      Disappointing that this long standing and easily reproducible battery charging bug is still there in the latest firmware version. As discussed in other threads I've speculated that this problem only hits those who leave the unit on the charger all the time (like I do) so that the battery never gets a chance to run the device, and that the battery management system in the device does not account for self discharge in the battery.

      Therefore after a few months the battery has self discharged itself down to say 50% (NiMH have relatively high self discharge compared to Lithium Ion) however the battery management system believes it is still fully charged because the unit has been running off power instead of battery the whole time so no battery use has been recorded, therefore it doesn't attempt to charge it. Making it think the battery is missing or faulty then restoring the battery tricks it into initiating a full charge.
      Last edited by DBMandrake; 18 May 2017, 08:59 AM.

      Comment

      • G4RHL
        Automated Home Legend
        • Jan 2015
        • 1580

        #5
        Sounds very logical. Mine nearly always shows it is 50% charged when I take it off the stand. Perhaps I should take it off the stand more often.

        Comment

        • paulockenden
          Automated Home Legend
          • Apr 2015
          • 1719

          #6
          The problem is if you are using the device as a temp sensor for a zone. Every time it charges the battery the unit warms up. You can actually feel this if you touch it while charging, but even more noticeable if you point a thermal imaging camera at it (yes, I *am* that geeky!)

          That's probably why the system minimises how often it tops the battery up. Perhaps there should be a routine that fires in the early hours of the morning (when this temp rise won't be so important) and which tops up the battery if it's lost more than, say, 20% charge. That should mean it doesn't happen that often.

          Comment

          • alexstephenson
            Automated Home Jr Member
            • May 2017
            • 15

            #7
            The evohome Controller uses rechargeable batteries which should not need to be replaced. If the batteries need to be charged place the Controller back on a powered Table Stand or Wall Bracket.

            Comment

            • gordonb3
              Automated Home Ninja
              • Dec 2016
              • 273

              #8
              Oh man, this thing has bugged me from the start. From the very first time I installed the system, every time I pulled the controller from the main power the battery would run flat within 20 minutes. I followed DBMandrake's trick (took some time to figure out where the battery was - not so obvious at all) and for the first time I was able to take it off external power for over an hour and the battery then still indicated being full. Thanks a million!

              Comment

              • DBMandrake
                Automated Home Legend
                • Sep 2014
                • 2361

                #9
                Pleased to be of help. You should be able to get about 2-3 hours off the dock before the big red modal "please place the unit on the dock" message appears, and then about another 2 hours after that until it actually runs out and stops functioning.

                Strange that yours wouldn't fully recharge after running out previously - definitely a bug in the charging algorithm, I notice that yet again mine is now indicating half charge when I remove it from the dock but will not charge when I put it back on the dock. It's literally less than a month since I applied the workaround last.

                C'mon Honeywell, it's not that hard to program a NiMH battery charger. Nearly 2 years without this bug being fixed is a long time by anyone's standards...

                Comment

                • gordonb3
                  Automated Home Ninja
                  • Dec 2016
                  • 273

                  #10
                  Well, I usually have that thing on the wall mount. I do have this recurring issue in my home though that I sometimes loose connection with one or more units on the top floor. Nothing to do with Evohome, the same happens with the (Buva/Stork) airbox. One other thing I noticed when transporting the controller is that when you set it back on a stand that is not plugged in it instantly reboots. Definitely seems to be something wrong with the logic here.

                  Comment

                  • DBMandrake
                    Automated Home Legend
                    • Sep 2014
                    • 2361

                    #11
                    Rebooting when you put it on a stand that isn't powered is not normal. I certainly haven't seen that behaviour on mine. Is yours the wifi model ?

                    I'll tell you what it might be if you have the wifi model - the spring battery contact under the positive terminal of the battery tends to both go completely flat and also corrode. This causes a poor connection as the shoulder of the battery ends up pushing against the plastic housing rather than the metal tip contacting the spring.

                    The twisting of the case as you fit it to the dock is then possibly enough to cause the battery to loose contact momentarily and if there is no power from the base to keep it going it would reboot.

                    On mine I scraped the black corrosion off the battery contact spring and also stretched it out slightly in the middle. You might want to do the same.

                    Comment

                    • gordonb3
                      Automated Home Ninja
                      • Dec 2016
                      • 273

                      #12
                      Nope. This is a pre wifi model (928srt that I sourced through Amazon Germany). Are those coil springs you refer to? No such thing on my controller. The plus is a fixed contact, only spring action is from the bend strip that is the negative contact. Did note some surface corrosion there, but I don't think it is possible to move the battery by applying any kind of twisting or pressure on the outside. Also: it kind of seems that this would be chance behaviour, but this happened every time. It might have been related to the battery actually being completely dead though.

                      Edit: negative! Still happens. Display shows 'NRST Pin Reset'?
                      Last edited by gordonb3; 11 June 2017, 11:15 AM.

                      Comment

                      • bruce_miranda
                        Automated Home Legend
                        • Jul 2014
                        • 2307

                        #13
                        I had noticed that reboot on unpowered stand issue on the Mk2. Infact it used to go to the Software version screen. Didn't realise it still did it.

                        P.s. our posts crossed. Yes I remember the Mk2 used to do this.

                        Comment

                        • IM35461
                          Automated Home Sr Member
                          • Jan 2012
                          • 69

                          #14
                          My pretty new units battery went a bit funny after the unit rebooted to install the latest software.

                          After that it never read full until I let it run on battery power till it died and then let it charge up again.

                          Comment

                          • DBMandrake
                            Automated Home Legend
                            • Sep 2014
                            • 2361

                            #15
                            Originally posted by IM35461 View Post
                            My pretty new units battery went a bit funny after the unit rebooted to install the latest software.

                            After that it never read full until I let it run on battery power till it died and then let it charge up again.
                            Probably just due to the reboot though, as the bug was there from the beginning in all versions.

                            Comment

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