HP-19C Batteries

[teenix]

Hi all,

Just wondering what type of battery is being used these days and whether the low battery indicator is still of any use.

cheers

Tony

[dmh]

Vintage Calculators sell 3D printed battery packs for these with 1000mAh Tenergy Nickel-Cadmium batteries.

I'm currently using 4 x standard AA batteries.

I assume the existing low battery circuitry will work with at least the NiCad batteries?

(02-14-2023 12:09 AM)teenix Wrote:  Hi all,

Just wondering what type of battery is being used these days and whether the low battery indicator is still of any use.

cheers

Tony

[Jonas Sandstedt]

Hello Tony,

I have a solution my working 19Cs that I have described previously and repeat it here since I think it works so well.

https://www.hpmuseum.org/forum/thread-17716.html

Each kit I have is bought at Amazon and includes an USB charger such that the battery pack can be easily removed and safely charged outside the calculator. The kits are fairly inexpensive, about 140SEK, see for example

https://www.amazon.se/gp/product/B085WVH...UTF8&psc=1

A connector is needed to be acquired and soldered to the battery pack, and these are sold in bundles (the connector polarities red/black may not correspond those of the battery pack). This ensures safe charging, even relatively safe inside the calculator (but why risk it).

The low power indication works as well for this battery pack.

Best regards
Jonas

[teenix]

Thanks for the info :-)

Attached is the prototype 19C replacement CPU and Printer boards, almost ready to get made up. I might add adjustable low battery detect.

cheers

Tony

[Jonas Sandstedt]

These do look very exciting Tony.
I will be one of the customers in line when they are ready.

Best regards Jonas

[tangdfx]

This is the great news for year 2023.

HP19C is my favorite HP classic calculator.