Hurricane II: An HP-41C Battery Pack w/ USB

[Hans Brueggemann]

hi bas,
i have currently two working prototypes on my bench. proto #1 is feeding a HP-41CX plus CLONIX. it is right now commencing a 2000 h stand-by test to figure out as to whether real-life battery drainage complies with calculations. i'm looking for battery droop in mV / day figures.
proto #2 is feeding an early HP-41CL which is serving as (shame!) 4-banger on my desk to figure out how (in-) convenient it is to keep it going in daily usage. also, i need to investigate the accuracy of the charger circuitry and its impact on the "mileage" that you can get out of one full charge cycle.