Hello!
In short, the aim is to create a device that is completely autonomous. It would sleep ~ 99% of the time, wake up, do some processing, and transmit the data. It would be powered at 3.3 V.
Average consumption would be somewhere around 1mW, with 100 mW peaks when the device is processing.
Going beyond this introduction, I'm interested at this stage to do some tests to determine the degree to which the solar cell + battery can power the device in an autonomous manner during a whole day. In other words, if the energy captured by the cell in 24 hours is sufficient to operate the device.
As the power source will go through a 3.3V voltage regulator, I guess I must use a battery with at least 4V. At this stage I didn't do any research regarding the type of battery which I should use, but it should be one able to handle multiple charge/discharge cycles as the battery will function as a buffer between the solar cell and the device.
The first thing I want to do now is find a resistor which when connected to the solar cell simulates the load which charging a battery would imply. After that, I could measure the voltage on the resistor and determine the output power of the solar cell in different lighting conditions.
So I have some questions:
1) How can I determine the resistor value to simulate a charging battery?
2) I saw that each solar cell has a maximum power output at a specific voltage and current. How can I choose the solar cell so that when connecting it to the battery, the power generated is maximal?
3) Considering that the battery is permanently connected to the solar cell, does it lose much of its life cycle?
Thank you!
Alex
In short, the aim is to create a device that is completely autonomous. It would sleep ~ 99% of the time, wake up, do some processing, and transmit the data. It would be powered at 3.3 V.
Average consumption would be somewhere around 1mW, with 100 mW peaks when the device is processing.
Going beyond this introduction, I'm interested at this stage to do some tests to determine the degree to which the solar cell + battery can power the device in an autonomous manner during a whole day. In other words, if the energy captured by the cell in 24 hours is sufficient to operate the device.
As the power source will go through a 3.3V voltage regulator, I guess I must use a battery with at least 4V. At this stage I didn't do any research regarding the type of battery which I should use, but it should be one able to handle multiple charge/discharge cycles as the battery will function as a buffer between the solar cell and the device.
The first thing I want to do now is find a resistor which when connected to the solar cell simulates the load which charging a battery would imply. After that, I could measure the voltage on the resistor and determine the output power of the solar cell in different lighting conditions.
So I have some questions:
1) How can I determine the resistor value to simulate a charging battery?
2) I saw that each solar cell has a maximum power output at a specific voltage and current. How can I choose the solar cell so that when connecting it to the battery, the power generated is maximal?
3) Considering that the battery is permanently connected to the solar cell, does it lose much of its life cycle?
Thank you!
Alex