Battery life and HW & SW hacks to extend it?

[Vtile]

Is there any way to get longer battery life for the calculator, the stated 15 hours (wikipedia since HPs page doesn't mention it, I assume that I can blame the marketing folks) sound like a bad joke to me ..seriously..

Have anyone replaced the battery unit with bigger li-ion battery (elecrically and or physically) and custom back cover (100mph tape incluted)? I assume that screw mounted shield is a battery cover behind the unit.

Is there what kind HP specific of electronic charging circuitry added to battery itself or is it just typical Li-Ion stack with charging protection? Does the calculator itself have circuitry to handle bigger battery or will it kill the calculator? How many mA it draws in ready to calculate state? How many while CPU is at full use? What is rough average draw while working (use, no use, use basics, solve complex stuff, no use etc..)? What is the turn-off voltage and amperage?

Is there "hibernation" settings and backlight turn-off functionalities on firmware any other power saving methods in use than turn-off calculator? How long storage life the calc have when recharged to full. Is there a good power level indication?

Option for downclock it without lost of mathematical accuracy / loss of functionality except speed?

Easiest way to prevent it to not run out of juice while on road is of course to just take one of those cellphone USB power banks with it and piece of USB cable. The why I tend to not like new phones with recharge daily life span, it were so cool when Nokia got phone somewhere in mid 90s that actually did work like several days then later for a weeks compared to typical few hours to day where we are again.