Here's the battery holder story I promised. For those who just tuned in, this is what a MPD LP2032SM battery holder looked like after just a small number of battery insertions:
downloads.qi-hardware.com/people/werner/anelok/tmp/lp2032sm-cracked.jpg Also the similar MPD BLP2032SM, which would have been a "plan B", has the same problem and it's even worse there: downloads.qi-hardware.com/people/werner/anelok/tmp/blp2032sm-cracked.jpg More details: lists.en.qi-hardware.com/pipermail/discussion/2014-May/010617.html lists.en.qi-hardware.com/pipermail/discussion/2014-May/010618.html I mailed MPD about this problem two weeks ago but didn't get a response so far. Well, there's more fish in the sea ... I experimented quite a lot with CR2032 batteries during the last few years and have a collection of holders. These two are somewhat similar: MPD BA2032SM and Keystone 1060: www.digikey.com/product-detail/en/BA2032SM/BA2032SM-ND/257743 www.digikey.com/product-detail/en/1060/1060K-ND/303556 For comparison, here are all four: downloads.qi-hardware.com/people/werner/anelok/tmp/batcomp-top.jpg >From left to right MPD BLP2032SM, MPD LP2032SM, Keystone 1060, and MPD BA2032SM. The cracky ones are nice and small, while the other two are a bit larger. Here's a side-by-side height comparison between the BA2032SM and the LP2032SM: downloads.qi-hardware.com/people/werner/anelok/tmp/batcomp-ba2032-lp2032.jpg And here we have 1060 vs. LP2032SM: downloads.qi-hardware.com/people/werner/anelok/tmp/batcomp-1060-lp2032.jpg Each of them has its issues. LP2032SM and BLP2032SM fall apart. The 1060 retains the battery with surprising force, so you don't stand a chance without a screwdriver or similar tool. The BA2032SM has an ungainly appearance and cheap feel (but the ejection system works quite well). Of the three, I like the 1060 best. The quality issues of the LP2032SM and BLP2032SM aren't something I want to deal with, especially not if the manufacturer is unresponsive. The BA2032SM is just too big. The 1060 is also too long to fit nicely, but there are two ways to deal with this: 1) I can clip the solder pads to make it fit. That's what I plan to do for the next board. Since the holder can be glued down, we don't need the solder pads for mechanical stability. 2) There is also a through-hole variant, the 1059, which does fit. It would need a bit of special handling, e.g., trimming of the pins and possibly manual soldering, but I don't think this would be a huge problem for manufacturing. www.digikey.com/product-detail/en/1059/1059K-ND/315162 Alas, I don't have any of these at home, so I'll go with the 1060 for now. Money matters: at 1000 units, the LP2032SM would have been USD 0.64 each at 1200 units (2 reels of 600 each), the 1060 is 0.95 @ 1000 as cut tape and a surprising 1.21 @ 1000 on reels (500 each). The 1059 is 0.95 @ 1000 (no reels offered at Digi-Key). So it's an expensive part and it makes sense to keep looking for alternatives. - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
