From: charlie@xxx.net   
      
   On Mon, 30 Sep 2019 15:07:18 +1300, ~misfit~   
    wrote as underneath :   
      
   >On 30/09/2019 7:38 AM, etpm@whidbey.com wrote:   
   >> On Mon, 30 Sep 2019 00:19:07 +1300, ~misfit~   
   >>  wrote:   
   >>   
   >>> ... that I can use to drain alkaline cells and push the 'charge' into   
   either a lithium-Ion cell   
   >>> (for a flashlight), a phone or a powerbank.   
   >>>   
   >>> I have a combined wireless doorbell - inside/outside thermometer that I   
   quite like. Unfortunately   
   >>> it won't run on NiMH cells and only uses alkalines down to 1.33v. (It's   
   the only thing I have that   
   >>> doesn't run on rechargeable cells.)   
   >>>   
   >>> The sender uses AAA cells and the receiver uses AA cells and I buy good   
   quality (expensive) cells   
   >>> to get the longest run-time between changes (as it's a PITA to re-pair   
   them and re-set the clock in   
   >>> the receiver too often). I though of converting the receiver to run on a   
   single 14500 Li-Ion cell   
   >>> (AA size) and a buck regulator or even a wall-wart but that still doesn't   
   solve the issue of the   
   >>> sender.   
   >>>   
   >>> I dislike throwing good quality alkalines away when they still have ~65%   
   of their capacity   
   >>> remaining but have had enough leak-disasters to not want to put already   
   semi-discharged cells in   
   >>> remote controllers etc. where they then get forgotten about until things   
   stop working. (I've never   
   >>> had an Eneloop leak and they run my remotes for about 3 years between   
   charges.)   
   >>>   
   >>> So I'd like to make a gizmo that takes a single alkaline and pushes out   
   ~5v through a USB cable for   
   >>> as long as the cell has juice, preferably at a reasonable current. I have   
   a few different pre-made   
   >>> boost modules from the usual suspects but when I tested one the output   
   voltage curve dropped with   
   >>> the input so that it wasn't very successful.   
   >>>   
   >>> If anyone has any ideas for something I can put together with a bit of   
   veroboard or similar I'm all   
   >>> ears. I'm tired of having loads of half-used cells sitting around but   
   don't want to just chuck them   
   >>> away. I've thought of this before but it's fresh in my mind as I've just   
   bought a 32-pack of each   
   >>> size cell and they cost quite a chuck of change.   
   >>>   
   >>> TIA.   
   >> If there is room for two AA cells in the sender why not substitute a   
   >> lithium pouch cell and a regulator? Then you could charge the pouch   
   >> cell while in the sender and never worry again about pairing the   
   >> devices?   
   >> Eric   
   >   
   >The sender uses two AAA cells and is very tightly packaged. Also it's   
   waterproof as it's outside in   
   >the elements so I don't want to mess with it too much.   
      
   Trouble is that the boost circuit takes a proportion of the available   
   battery power to run, so trade off calculation required!   
   See:   
   https://www.ebay.co.uk/itm/DC-DC-1V-1-2V-1-5V-1-8V-2-5V-3V-to-DC   
   3-3V-Step-UP-Boost-Power-Supply-Converter/192311866315?hash=item   
   cc6ae33cb:g:ho0AAOSw-QZZwnWh   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)