I’m making a charging dock for the calculator, using the 2 contacts on the bottom. So, I’ve already made a 3D printed base, I just need to connect a USB to it. I’ll put some contacts on the base, and strip a USB, soldering it to it.

I’ve heard in other places that the contacts on the bottom are connected to the same system as the USB port, so that it can be protected from larger voltages. Here’s where my questions come in:

Are the contacts actually connected to the BMS?

Do any specific USB cables output more power? (Stupid question)

And is there an upper limit to the amount of voltage the BMS can handle?

Yes, they are connected to the bms otherwise the battery would probably expload.

I terms of USB C, yes, some cables handle more power. However, the CE only draws a peak of 2.5w (500ma at 5v) so any USB cable will be rated to handle that.

Don't give the calculator any more than 5v. Any higher and you're asking for trouble.

Sounds like a cool project! Please share some photos when you're done!