Spice vs Woodstock battery charger

[teenix]

(11-20-2022 12:20 AM)husmus Wrote:  Has anyone used a Spice battery charger 82087B 10V AC 1.8VA MAX to connect to a Woodstock calculator. Woodstock uses the 82024A 10V AC 0.8W MAX charger. I'm thinking I could 3D print a converter connection block.

The charge circuit for the Woodstock and Spice seem the same, which would suggest the transformers are similar. the 1.8VA really needs the Power Factor of the transformer to get the watts value, but VA is generally higher than watts so maybe compatible.

Unfortunately, as mentioned many times in this Forum, using chargers of this type presents the real possibility of a dead calculator, so the best answer would be to externally charge the batteries.

You can still use the charger for external charging.

The batteries are connected in series, one AC wire connected in series with a diode (IN400x or similar) and an 8.2 ohm, 2W resistor and top battery +ve. The other AC wire to the bottom battery -ve.

Edit:
The above charging circuit applies only for the original NiCad battery types supplied with the calculator at purchase. If you intend to use different battery technologies, then a charger that suits the battery type will be required, and again, charged externally.

cheers

Tony