Thinking about an HP-41CL

[Dieter]

(07-25-2016 09:10 AM)renif Wrote:  In the past there was a real market of third party HP-41c accesories, also N size chargers. Alas, these devices made by the german supplier W&W are absolutely rare these days.

Back in the Eighties a company named "Corvallis team" offered several accessories as well. Although they seem to have been specialized in HP41 software, there were also chargers, port extenders, special cases and much more.

(07-25-2016 09:10 AM)renif Wrote:  I were lucky to get one from a friend in exchange for a well used 32sII. A very nice and reliable device which saved me money for many years. Regarding its simple construction (standard cell holders on top of a standard electronics casing)

This looks like a standard charger for one or two 9 V batteries (6LR61). Their typical capacity (100...120 mAh for NiCds) is quite similar to N-size NiCds of the Eighties, so the charging current should fit. It should be mentioned somewhere on the back of the case. These devices usually offer no charging control at all, maybe at best there is a simple timer, typically set to 14 h.

(07-25-2016 09:10 AM)renif Wrote:  it should even be possible to tinker a comparable charger from a AA size model using appropriate N size battery holders. Of course, that would cost more than four ot those adapters shown above.

But you also get a much, much better charger. Consider the suggested BC700 which features decent charging control and short charging times in its default 200 mA setting when combined with 500 mA NiMH cells. However, do not try charging NiCds with such currents since their much lower capacity will result in a relative charging current that can and will damage these cells.

Nowadays a processor-controlled charger with a sufficiently low charging current (like the mentioned BC700 or IPC-1L), combined with 500 mAh NiMHs in AA-adapters, should be close to a perfect solution.

Dieter