(2017-11-13, 11:16 PM)JD1 Wrote:(2017-11-13, 11:03 PM)shark24 Wrote: As mentioned before. Most of the power banks can't be charged and discharged at the same time. Besides the probable capacity problems the pi would still suck the juice out of the power bank after the shutdown.
I guess we cross posted .... I don't see any reason why you shouldn't charge/discharge at the same time (I am pretty sure I have seen commercial products that do both although I can't recall the particular products). If you have a timer of some kind for secondary power shutdown then you will not kill the power bank.
Yes there are some power banks that handle simultaneous charge/discharge but for me most of products out there didn't do the trick.
Yes if you have the timer mentioned above you can easily cut off the secondary power supply. Again I'm using a mosfet as a switch and a capacitor of a certain size to time this process