Part 5/9:
The PowerCheck worked by creating a circuit connected to a "tiny heater" when the pressure was applied. The resulting heat would turn a thermochromic indicator yellow, depicting battery status visually—completely innovative for its time! The temperature setting of 70 degrees Fahrenheit was crucial, ensuring that the readings were accurate under specific conditions. However, the effectiveness of the test relied not only on the battery's health but also on the user's ability to apply the necessary pressure correctly, which has been described as a somewhat frustrating experience.
Moreover, each test utilized some of the battery's charge, which, while providing a more accurate reading under load, also meant that testing frequently would deplete battery life more quickly.