Measuring and monitoring a power source

A battery testing system comprising:

• (a) a plurality of battery sensors, each sensor adapted to be associated with one of a plurality of batteries to be tested, each sensor comprising:
• (i) a microcontroller configured to:
• (1) analyze frequencies of background noise at a battery to be tested during a test operation;
• (2) determine, based on an analysis of the background noise, a duty cycle of a desired pulse width modulation (PWM) signal to be applied to the battery, the duty cycle being selected such that, when applied to the battery, it at least approximates an AC signal having a frequency that has been determined by the microcontroller to provide optimal test results in view of the background noise;
• (3) generate the desired PWM signal;
• (4) analyze a response from the battery resulting from application of the PWM signal thereto;
• and, (5) based on the response, determine at least one attribute of the battery;
• and,
• (ii) circuitry, including a switch, for applying the PWM signal to the battery;
• and,
• (iii) a communications interface;
• (b) a controller adapted to communicate with (i) the sensors via each sensor's communications interface and (ii) a remote management server.

A battery testing method comprising:

• a) analyzing frequencies of background noise at a battery under test;
• b) determining, based on an analysis of the background noise, a duty cycle of a pulse width modulation (PWM) signal to be applied to the battery, the duty cycle being selected such that, when applied to the battery, it at least approximates an AC signal having a frequency that has been determined by the microcontroller to provide optimal test results in view of the background noise;
• c) generating the PWM signal, and applying the PWM signal to the battery under test;
• d) analyzing a response from the battery resulting from application of the PWM signal thereto;
• and,
• e) based on the response, determining at least one attribute of the battery.