The first Texas Instruments calculator, the Datamath, used rechargeable NiCd (nickel-cadmium) batteries. They were soldered together and firmly mounted inside the calculator housing. Later the people at TI changed the housing and added a trap door. From this time customers could either use standard AA-cells or rechargeable batteries of the same size.
Starting with the SR-50 Texas Instruments introduced so called "Battery Packs" or BP's. The technique used inside these removable BP's changed over the time from a simple battery holder to a module with integrated electronic to charge the battery and lift the voltage of one or two cells to a more common 9V voltage.
Although most of the BP's look very similar, they are not compatible. Here is a list to give a reference from a BP to the possible TI calculator and the associated Charger (US and European models).
Don't miss this link: Repair a Battery Pack.
Fine print: This list was compiled carefully but we are not responsible if someone destroys his or her calculator due to information of it.
If you have additions to the above article please email: joerg@datamath.org.
ゥ Joerg Woerner, 2001 - 2022. No reprints without written permission.