Circuit Lake

Electronic Project and Circuit Collection

Battery Capacity Meter, Battery sAVR

02/04/2010 Category: AVR, Data Acquisition, Measurement, Project

The Battery sAVR is an intelligent battery capacity meter that will log the discharge of a single primary or secondary cell over a period of time. But it’s more than a dummy load and data logger, with Atmel ATtiny26 AVR microcontroller, the Battery sAVR can emulate 3 different types of loads in real-time – Constant Current, Constant Power, and Constant Resistance. The user can also define a cutoff voltage down to 0.8V.


David Jones, the project designer, said that the project is powered completely from the battery under test. It also dynamically compensates for its own current consumption using differential ADC in the ATtiny26 device. The project firmware is written in C language and only need 1Kword memory of the ATtiny26. The data (time, voltage, and current) is stored in the internal EEPROM memory of the ATtiny26, which is automatically fully utilized regardless of the cutoff voltage or discharge time. The data can be exported via a PC serial port into CSV format for easy graphing in your own spreadsheet.

Battery Meter
Project Detail and Documentation