Wireless charging for a HP-25 calculator

[jwr]

(05-12-2021 02:07 PM)PANAMATIK Wrote:  It makes my HP-25 Low Power circuit useless,

It most definitely does not — I've seen your work and I highly respect it. In fact, I've been thinking about buying your kit. Your solution is better in many ways except one: it requires serious modifications to the internals of the calculator.

The biggest drawback of this rechargeable battery pack is that if you don't have a 25C, you will lose memory contents when you switch the calculator off. And even if you have a 25C, your display mode won't be remembered, for example, you only keep the registers and program memory.

Very happy to read what you wrote about the low-battery indicator: I was worried and a bit disappointed about the short time (it was actually closer to 10 minutes), and never knew that it was originally designed to be even shorter. Good news!