obsolescence, batteries

   In reply to one of my earlier posts, SDF colleague (is that a good
   description for somebody on the same system?) solderpunk recently wrote
   about [1]battery standards and [2]gadget obsolescence. I share those
   views.

   But what about the advances in power density of consumer batteries,
   what did we gain with the Li-type batteries?

   I have made a quick survey of rechargeable batteries at home: Li-ion in
   various phones (smart and feature), and NiMH AA and AAA batteries. (I
   cannot say what's in my Android tablets, because those are not easily
   removed from the device). I have weighted them and calculated the
   energy density based on what's written on them -- of course this may be
   under optimum conditions, but assuming all manufactures exaggerate more
   or less the same way, it should still be somewhat comparable:
     * Li-ion: 0.2, 0.2, 0.05 Wh/g (the last a very small and older item)
     * NiMH: 0.06, 0.1, 0.1 Wh/g

   So we could say we gained about a factor of two in weight for the same
   energy density -- but does it really matter a lot, whether you carry 25
   or 50 g of batteries for a total of let's say 200 g (typical
   smartphone)?

   But we lost on
     * safety: never heard about burnt NiMH batteries, but there are
       entire chapters about transport safety measures for Li batteries in
       IATA documents
     * availability/replacement: just keep some alkaline AA and AAA, and
       you can replace your rechargeable ones in an emergency
     * environmental protection, as solderpunk nicely pointed out: the
       more different batteries you need, the more waste you generate

   And did I already mention obsolescence..?

   .:.

References

   1. gopher://sdf.org/0/users/solderpunk/phlog/more-battery-thoughts.txt
   2. gopher://sdf.org/0/users/solderpunk/phlog/lithium-blues.txt