Hi, I am working on optimizing the battery usage I did couple of experiments and found some results. I am using Green LED, ADC to read battery voltage and timer to wake up from sleep. In the experiment I sent some random temperature and humidity data along with battery data in interval of 15 minutes for about 12 hours.
I am using semaphores to implement sleep and I am keeping the LED in Off when not in use. It will turn on when it wakes up from sleep and then goes off immediately.
Initially when I noted down the battery voltage it was about 4.14V and after 12 hour it was 4.10V. So there is a difference of 0.04V in 12 hour means 0.08 in 24 Hour. Since the minimum voltage is 2.75V for Li-ion battery it may take hardly 18 days to drain the battery to this minimum.
Maximum battery voltage = 4.2V
Minimum battery voltage = 2.75V
Voltage drop in 1 day = 0.08V
Battery voltage is not a good indicator of the battery capacity.
You need to know the current consumption you have to have a better gauge on how long your battery can last. You also need to know the capacity of the battery you are using.
As you see in this graph, it is hard to correlate the exact capacity on the voltage level unless you do the characterization of the battery to the device itself. The voltage level is affected by how much current drain the circuit has as well as the operating temperature.
Hi Carl, Thanks for that. I did some experimentation and found some results. I am using ICR-18650-26F Li-ion battery with a nominal capacity of 2600mAh.
In sleep mode the WisBlock is consuming around 40uA (50uA max) and while sending payload to gateway it uses around 77mA (according to documentation max is 130mA).
Is this a good value to go? I need the battery to be working for at least 1 year.
