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Advice on rechargeable/standard batteries for locks and blinds

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    Advice on rechargeable/standard batteries for locks and blinds

    There are a couple of posts on this topic but not recently so I thought I would start a new one now that rechargeable lithiums are readily available.

    I have four Schlage z-wave locks and a lot of Somfy blinds that are all powered by AA batteries. I have been playing around with different batteries - so far I have settled on standard alkaline AAs for the locks and Lithium AAs on the blinds.

    Schlage doesn't recommend Lithium as they produce "undesirable results". As far as I can tell this means that the lock will go from working correctly with a reasonable battery level to not responding and completely dead within a day. The key is figuring out what that drop-off point is.

    I am trying some rechargeable lithium batteries in one of the locks:

    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

    They are down 10% in 2 weeks. The lock is barely used. So this doesn't look promising.

    I also tried these batteries in one of my somfy blinds. The blind goes up and down once a day and the batteries ran out in a matter of weeks.

    It could be this particular brand of rechargeable batteries is just no good.

    What have others had success with?

    #2
    Rechargeable Lithium tech tends to have a high 'self discharge' rate.
    Low discharge for Lithium just means 'won't drain completely before you manage to install them'...

    I would suggest using Alkalines in the locks for just that reason.

    I have blinds, too, with the cheap 433MHz remotes. But they run on 12V. Just need to figure out how to not make it look completely arsed up.

    Comment


      #3
      Your expectations dictate what type of battery technology you should be using. Once you choose a battery technology you need to throw away your preconceptions of how they should work. Let's use lithium batteries as an example, they do not have the same smooth/linear discharge rate as alkaline batteries, hence they will stay at a certain level for a long time and then suddenly drop-off to a very low level one day, using the current measuring methods built-into battery powered devices.

      Just off the top of my head:

      High-quality alkaline
      Pros: Long lasting production use, predictable discharge rate, longest storage-charge shelf-life (I think some Duracells are guaranteed for 5 to 10 years).
      Cons: One time use, continuous cost to replace, ends up in the garbage sooner than rechargeable.
      Comments: In my Schlage locks I find these can last 6 - 12 months, dependent on temperature exposure and usage.

      Non-rechargeable quality Lithium batteries
      Pros: Probably longest lasting production use (many battery powered sensors use Lithium coin-cells and last 1 to 2 years), good storage-charge shelf-life
      Cons: Non-linear/unpredictable discharge rate, One time use, continuous cost to replace, ends up in the garbage sooner than rechargeable.
      Comments: All my Zigbee and some Zwave sensors use these.

      Nickel–metal hydride (NiMH) rechargeable batteries
      Pros: Currently dominates the marketplace, meaning lower initial-cost and easy availability; various mAH sizes (larger storage capacity available); don't end up in the garbage right away, predictable discharge rate.
      Cons: Bad self-discharge (shelf-life) you'll need to have these sitting in a charger to use right away, average production use time (you'll end up changing them out constantly).
      Comments: I used to use these everywhere

      Low self-discharge nickel–metal hydride (NiMH) rechargeable batteries (Sanyo Eneloops)
      Pros: Superior storage-charge shelf-life compared to regular rechargeable, don't end up in the garbage right away, predictable discharge rate.
      Cons: Higher initial cost than regular rechargeable
      Comments: I now use these everywhere where battery swapping is easy, in my locks I get about 3 to 4 months of use before swapping them with a freshly charged set. I personally like keeping as much stuff out of the garbage stream as possible.

      Rechargeable Lithium batteries
      Pros: Good production use time, don't end up in the garbage right away.
      Cons: Higher initial cost than regular rechargeable, Non-linear/unpredictable discharge rate.
      Comments: My only experience with these are my power tools, I will get around to buying a sett of AAs batteries to evaluate

      Hope this helps, of course YMMV

      Comment


        #4
        +1 on Sanyo Eneloops
        and I would add the MH-C9000 charger.

        Comment


          #5
          Just as an FYI, I use an old LaCrosse BC-900 charger which has all kinds of programmable parameters, including refresh mode (continuous discharge/charge cycles) to help older batteries regain near their full storage capacity.

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