Need batteries for HP-31E

[Maximilian Hohmann]

Hello!

(10-30-2023 04:12 PM)ctrclckws Wrote:  But, seeing all of these battery cautions reminds me of why I am leery of buying an electric car.

Electric cars use a completely different kind of batteries than those 40+ year old calculators! Most importantly, the batteries have integrated battery management systems (https://en.wikipedia.org/wiki/Battery_management_system) which protect the battery cells against overcharging, overvoltage, overcurrent and deep discharging. The cells are balanced, i.e. regulated individually to the same voltage, so that stronger cells can not reverse charge weaker ones (which is one of the main chauses of battery failure in calculator battery packs).
Thereby all the factors that cause the batteries inside calculators to eventually leak are eliminated. Additionally, the battery housings in cars are made from plastic which can not be corroded through by the electrolyte like the thin sheet metal housings of our calculator batteries. And, contrary to some common belief and urban legends, the battery type used by most car manufacures is Lithium-Iron-Phosphate (LiFePO4) which, other than the Lithium-Polymer ("LiPo") batteries used in small devices like smartphones, does not suffer from the "thermal runaway" phenomenon which can cause battery fires and explosions.

The short version of my long offtopic blabla: Our electric car is one of the three best things I ever bought. I will never return to petrol driven cars. Statistically, only 5 percent of car fires occur with electric vehicles - a figure already corrected for their smaller number. Maybe one of the reasons that the insurance for our electric car costs less than for the previous petrol one. And for peace of mind, the manufacturer gives 8 years warranty for the battery. By the way: the same type of battery is used for power storage in photovoltaic home electricity generation. The manufacturers - at least here in Germany - give 20 years warranty for the batteries. One wishes that HP had done the same with their calculators ;-)

Regards
Max