Fun times eh? I agree, NIMH is the most difficult thing I have ever had = to charge. Not so bad if it's always in a shirtsleeves environment, but th= at printer project required the printer to be able to live in a car, which = actually prohibited charging those cells in many situations at all. The original batteries that I specified were from a Japanese company, and e= xactly zero of those ever malfunctioned, but the China ones were HALF the c= ost!! So management insisted we use them. =20 These days I see on Facebook people are making "powerwalls" using hundreds = of 18650 cells and soldering wires directly to the cells... -- David VanHorn Lead Hardware Engineer Backcountry Access, Inc. 2820 Wilderness Pl, Unit H Boulder, CO =A080301 USA phone:=A0303-417-1345 =A0x110 email:=A0david.vanhorn@backcountryaccess.com=A0 -----Original Message----- From: piclist-bounces@mit.edu On Behalf Of Russel= lMc Sent: Friday, March 15, 2019 6:57 AM To: Microcontroller discussion list - Public. Subject: Re: [EE] transistor gain variations On Sat, 16 Mar 2019 at 01:36, David Van Horn < david.vanhorn@backcountryacc= ess.com> wrote: > Yeah, I got bit BAD by Chinese NIMH cells some years back. It turned ou= t > that they were not including as much of a certain catalyst as they=20 > should to help the H2 and O2 recombine. The result was a spectacular=20 > failure that could occur spontaneously, even with the cells completely=20 > removed from the product and just sitting on the table. > Yes. Your accounts of your NimH woes cautioned me when I became involved. Up to about 1600 mAh, maybe 1800-2000 the catalyst levels allow trickle. 2000 mAh up trickle charge is a non-no. I came to dislike NimH severely in the applications I was involved with. They are OK in a controlled environment where any of the major charge termi= nate methods can be relied on, but in a variable and high temperature envir= onment with variable or no charge they are nasty to handle well. LiIon, despite all the claims re them being 'tricky'. are a joy to deal wit= h compared. Russell > -- > David VanHorn > Lead Hardware Engineer > > Backcountry Access, Inc. > 2820 Wilderness Pl, Unit H > Boulder, CO 80301 USA > phone: 303-417-1345 x110 > email: david.vanhorn@backcountryaccess.com > > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive=20 > View/change your membership options at=20 > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclis= t --=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 .