BP - Battery Packs

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.

Type Cells Voltage TI calculators Charger
BP1 3*AA 3.6V SR-50, SR-51 AC9200 AC9900
BP1A 3*AA 3.6V BP1 could be replaced with BP1A
SR-50A, SR51A, SR52, SR56
TI-58, TI-58C, TI-59
AC9130 AC9900/E
AC9131 AC9900/H
BP2 2*AA 2.4V TI-2550 II AC9130 AC9900/E
BP3 1*AA 1.2V TI-2550 III AC9130A AC9900/E
BP4 2*AA 2.4V TI-2550-IV  AC9900/H
BP5 1*AA 9V 1976-1977: SR-40, TI-30, TI-31, BA
RK1 (Rechargeable Kit introduced 1976)
AC9131 AC9900/H
BP6 2*AA 2.4V SR-51-II, TI-57 (1977) AC9131 AC9900/H
BP7 2*AA 9V TI-51-III, TI-55, TI-57 (1978), TI-42 MBA, MBA AC9132 AC9900/R
BP8 2*AA 9V 1978-1981: SR-40, TI-15, TI-30, TI-31, TI-33, TI-41, TI-45, BA, BA1, Money Manager, Programmer
RK2 (Rechargeable Kit introduced 1976), RK3 (European Version)
AC9132 AC9900/R
BP9 2*AA 9V TI-45   
BP88 1*AA 1.2V TI-88 AC9133
BP200 4*D 4.8V SR-22  AC9222

 Fine print: This list was compiled carefully but we are not responsible if someone destroys his or her calculator due to information of it.


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Joerg Woerner, 2001 - 2021. No reprints without written permission.