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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:

    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?

    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.


      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


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


          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.