At 11:19 AM 6/29/2015, John J. McDonough wrote: >I've largely given up on rechargeables for most applications. Alkalines >last so much longer, you don't have the charging hassles, and if you use >enough of them, they are cheap. But then I haven't messed with the >Eneloops. Normal NiMH have such an internal discharge that you have to >charge them right before use, and NiCd need so much mothering. I may >have to try the Eneloops, although right now I can't think of an >application for them. I work with Broadcast audio and intercom as a side hobby. We use=20 rechargeable NiMh cells in the wireless intercom packs but not in=20 wireless microphones or IFB receivers. Each wireless intercom pack (Telex BTR-800 or BTR-80n) uses 6- "AA"=20 cells. Alkaline cells (Procell) last typically 12 hours when the=20 pack is in Push-To-Transmit mode and the Powerex 2500 mAH cells we=20 use are good for more than 10 hours. A tiny show will use 4 wireless=20 intercom packs, a large show will use 24 packs or more. A short show=20 (single day) uses two or three battery changes, a long show will use=20 several battery changes during setup and rehearsal and then (usually)=20 one battery change per show day. That's a *LOT* of "AA" cells. I did intercom for the largest outdoor entertainment venue during=20 Vancouver's 2010 Winter Olympics. I purchased approximately 2 full=20 shopping-carts worth of Kirkland "AA" cells from Costco (144 cells=20 per package) during the not quite 1 full month that I was on site. This one occasion caused the fellow that I work with to put some=20 serious research into finding acceptable rechargeable cells and=20 chargers. After much looking and some testing, we settled on the=20 Powerex 2500 mAH cells and MaHa 8-slot "smart" AA-cell chargers that=20 were available at that time. That's what now ships with the intercom systems that go out to the=20 various broadcasters. A single case that holds 4- 8 cell chargers=20 and 64 "AA" cells. There is also a couple of multi-slot 9V chargers=20 and a bunch of rechargeable 9V batteries but no one uses them - they=20 just aren't up to par compared to alkaline Procell 9V primary batteries. Some time after that, I had the incredibly great fortune to be asked=20 to do the intercom for the film crew that was making a 3-D movie with=20 the rock group Metallica. This was, to me, a massive production=20 involving more than 150 people. Something like 18 channels of=20 intercom and just shy of 100 people on headset plus another 50 or so=20 people on two channels of walkie-talkie. Not a complex system (quite=20 simple, actually) but certainly the most numbers of people all=20 working together via the intercom system that I've done. I took with me 3 of those battery cases I mentioned earlier plus=20 double the usual number of AA cells. That gave me the ability to=20 charge up to 96 cells at any one time and 3 complete sets of extra=20 cells that were cycled among all the wireless packs. No problems whatsoever. The reason this technology works so well in this particular situation=20 is that you have people know the limitations of these particular NiMh=20 cells and who take the time to ensure that they are used properly. In particular, these NiMh cells have the somewhat standard=20 self-discharge rate of something like 30% per week of=20 self-discharge. That means that you use cells that have been charged=20 sometime within the previous 24 hours. So: rechargeable NiMh cells aren't for everybody. But those Duracell=20 "Green" cells that I mentioned in an earlier message are sure awesome! dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .