3D Printed Sting 10 / 19C Battery Tray

[Jonas Sandstedt]

Hello,

I do not know to what extent you want your calculator to be in original condition, but the solution I propose only involve soldering two small wires to the battery contact tabs which already are covered with (old) solder. This provides a much more reliable electrical connection than the original contact solution between battery poles and the battery contact tabs, and if the wires are de-soldered and superfluous tin is removed, the calculator is brought back to original condition except that the old tin at the battery contact tabs has been replaced with some new tin.

The advantages involve a better electrical contact that reduces the risk of damage to the calculator during charging and the possibility to easily remove the batteries and charge them separately outside the calculators. This totally eliminates the risk of damage to the calculator during charging and a modern NiMH charger can be used (if NiMH cells are used). As shown in the photos, I use a USB charger that can be connected to a USB power source.

Furthermore, modern AA cells are slightly larger than the older ones, and therefore I think it is difficult to fit them properly in the original battery holders that can’t be re-assembled properly, and the battery cover is therefore sometimes hard to close. Dispensing with the need for a battery holder makes this handling easier as well.

Of course, it must be said all types of handling such as soldering and de-soldering involves a risk of damage, but for me it has worked well. Whatever you choose I hope it works well since the HP-19C is a really nice calculator.

Best regards
Jonas