Measuring and monitoring a power source
The disclosed battery monitoring systems and methods may minimize measurement errors due to noise and/or other disruptions. The sensor may generate a pulse width modulated signal that when applied to the battery forms an AC test signal having a defined waveform, frequency, amplitude, and/or duration. The sensor may measure the battery's response to the test signal. The resultant response signal may be measured to determine the health of the battery, including its internal admittance. The sensor may determine an optimum frequency to test the battery by scanning a frequency range and measuring the amount of noise present.
1. A device for testing an internal characteristic of a battery, the device comprising:
a memory to store a plurality of alternating current signal data values;
a processor to generate a pulse width modulated signal at the battery and to measure a response signal excited at the battery in response to the pulse width modulated signal, wherein a duty cycle of the pulse width modulated signal varies in accordance with the plurality of alternating current signal data values.
2. The device of claim 1 , wherein the processor measures a peak of the response signal.
3. The device of claim 1 , wherein the processor measures the response signal in accordance with a peak of the plurality of alternating current signal values.
4. The device of claim 1 , wherein the processor averages a plurality of measurements of the response signal.
5. The device of claim 1 , wherein the alternating current signal data values are sinusoid signal data values.
6. The device of claim 1 , wherein the processor calculates the internal characteristic of the battery according to an average of a plurality of measurements of the response signal.
7. The device of claim 6 , wherein the internal characteristic is internal admittance.
8. The device of claim 1 , further comprising a communications interface, wherein the processor transmits a measurement via the communications interface.
9. The device of claim 8 , wherein the processor receives a command to test the battery via the communications interface.
10. The device of claim 1 , wherein the processor measures a voltage of the battery at a plurality of frequencies.
11. The device of claim 1 , wherein the processor generates a characterization of a frequency spectrum and determines a frequency at which to test the battery in accordance with the characterization.
12. The device of claim 1 , wherein the processor determines that the battery is overcharged and draws current from the battery.
13. A method for testing an internal characteristic of a battery, the method comprising:
generating, via a microcontroller, a pulse width modulated test signal, wherein a duty cycle of the pulse width modulated signal varies in accordance with a plurality of alternating current signal data values;
exciting the battery with the pulse width modulated test signal; and
measuring a response signal of the battery as excited by the pulse width modulated test signal.
14. The method of claim 13 , wherein measuring the response signal comprises measuring a peak of the response signal.
15. The method of claim 13 , wherein measuring the response signal comprises measuring the response signal in accordance with a peak of the plurality of alternating current signal values.
16. The method of claim 13 , further comprising averaging a plurality of measurements of the response signal.
17. The method of claim 13 , wherein the alternating current signal data values are sinusoid signal data values.
18. The method of claim 13 , further comprising calculating an internal characteristic of the battery according to an average of a plurality of measurements of the response signal.
19. The device of claim 18 , wherein the internal characteristic is internal admittance.
20. The method of claim 13 , further comprising transmitting a measurement via a communications interface.
21. The method of claim 20 , further comprising receiving a command to test the battery via the communications interface.
22. The method of claim 13 , measuring a voltage of the battery at a plurality of frequencies.
23. The method of claim 13 , further comprising generating a characterization of a frequency spectrum and determining a frequency at which to test the battery in accordance with the characterization.
24. The method of claim 13 , further comprising determining that the battery is overcharged and drawing current from the battery.
25. A system for testing a plurality of batteries, the system comprising:
a plurality of connected battery sensors, wherein each battery sensor comprises a respective memory to store a plurality of alternating current signal data value and a respective processor to generate a pulse width modulated signal at a respective battery and to measure a response signal excited at the battery in response to the pulse width modulated signal, wherein a duty cycle of the pulse width modulated signal varies in accordance with the plurality of alternating current signal data values; and
a control unit in communication with each of the plurality of connected battery sensors, wherein the control unit receives measurement data from each of the plurality of connected battery sensors.