Converting HP-25 to NiMH batteries, possible?

[Maximilian Hohmann]

Hello!

(07-20-2022 06:06 PM)Wes Loewer Wrote:  Or perhaps it's something else I haven't thought of.

Yes, it's something different. There are countless threads on this topic but it is always worth reminding fellow collectors and calculator users: The chargers of the "Woodstock" series calculators have a poorly stabilised output voltage. Connecting one to the calculator without a battery in place will almost instantly kill the calculator. The same applies if the battery connection has a higher than normal resistance, which is often the case when the battery contacts have developed some degree of corrosion (they all have after 40 years). I am almost certain that most non-working Woodstocks have been electrocuted by their own chargers.
To save yours from this fate it is the safest option to store the charger as far away from the calculator as you can and charge the batteries outside the calculator.

Regards
Max