are the batteries for the PicoCalc just re-chargeable AA batteries, or something more specialised? if they aren’t rechargeable AA’s, where could you get them?
they’re rechargable 18650s. you can get them at any battery store, just don’t get them from amazon or aliexpress as a lot of fakes are sold there.
My personal recommendation is Samsung 35Es and I normally get my batteries from here.
