INTL 3:770/1 3:770/3   
   REPLYADDR k.nuyt@nospam.demon.nl   
   REPLYTO 3:770/3.0 UUCP   
   MSGID: <1ekevi540osl56bgi2j3samtrulv8bafar@dim53.demon.nl> 16e97be3   
   REPLY:  58c2c92d   
   PID: SoupGate-Win32 v1.05   
   On Sat, 16 Mar 2024 15:27:05 +0000, Mike Scott   
    wrote:   
      
   > ... For my part, and purely to use   
   > as a short-term standby for the Pi until mains resumes or the system can   
   > shut down cleanly   
      
   Please note that the Pi still draws power after shutdown,   
   because it has no power-off circuit of any kind.   
   There is a small but significant stand-by current (not just any   
   LEDs) that will eventually drain the UPS/batteries/whatever.   
   A dumb power source should at least be over-discharge protected   
   (think of protected Lithium batteries) or not be damaged by   
   total discharge.   
      
   Another issue: If grid power is restored before the UPS is   
   empty, the pi will not boot automatically. It only knows how to   
   handle unplug - replug the USB power.   
      
   So a good solution should remove power from the Pi after   
   shutdown, and switch it on again once the grid power is back.   
      
   Like David Higton suggests, MOSFETS are great for that.   
      
   --   
   Regards,   
   Kees Nuyt   
      
   --- SoupGate-Win32 v1.05   
    * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)   
   SEEN-BY: 10/0 1 15/0 90/1 103/705 105/81 106/201 128/260 129/305 135/225   
   SEEN-BY: 153/757 7715 218/0 1 601 700 840 870 930 220/70 221/1 6 226/17   
   SEEN-BY: 226/30 100 227/114 229/110 111 112 113 200 206 307 317 400   
   SEEN-BY: 229/426 428 470 550 616 664 700 240/1120 266/512 267/800   
   SEEN-BY: 282/1038 291/111 292/854 301/1 113 812 310/31 320/219 322/757   
   SEEN-BY: 335/364 341/66 342/200 396/45 460/58 633/280 712/848 770/1   
   SEEN-BY: 770/3 100 330 340 772/210 220 230 5020/400 1042 5058/104   
   SEEN-BY: 5075/35   
   PATH: 770/3 1 218/840 221/6 301/1 218/700 229/426