Safely charging my 65

[Don Shepherd]

(03-21-2015 02:32 AM)Brad Barton Wrote:  Having possibly fried the ACT chip in one of my HP-97 I'm reluctant to plug my HP-65 directly into the wall charger. I'd like to find some way to externally charge the battery.

I saw a thread by Geoff Quickfall mentioning that he was able to charge the batteries in his Classic calculator with one of the external HP-97 chargers. I have an external charger for the 97, but the "blades" don't line up with the pads on the 65 battery. I could make some modifications, but I don't know for sure how the polarity is laid out.

Does anyone know a safe, reliable way to externally charge HP-65 batteries?

Brad, you could try this.

I have never used one, but it sounds like it lets you charge your 65 battery outside of the calculator. I have always charged my 65 battery in the calculator using the standard AC adapter, and have never experienced a problem. I think the key is to never operate your 65 from the AC adapter with no battery being present in the calculator. I think that's the situation that will ruin your calculator.