HP-41CL and 82120D Power Bank.

[brouhaha]

(11-22-2023 01:57 AM)Diego Diaz Wrote:  But, since I designed the Power Bank to supply 6.3v, I'd like to confirm that this voltage (chosen on purpose to mimic a brand new set of alkalines) is safe enough to run a 41CL without compromising its life expectancy.

I don't know how high a battery input is safe, but since the nominal voltage of alkalines is 1.5V though much of their life, and when the calculator is "on" they are feeding a boost regulator (bipolar chip on the 41 logic board), I'd recommend setting the feedback for your regulator to produce 6.0V rather that 6.3V. I don't think there's any drawback to using 6.0V, nor any benefit to 6.3V.

I can't speak to the 41CL design, but if it's not designed for about 6.0V from the batteries, that's quite unfortunate.