I’ve gained a lot of resource, code and ideas from the Particle Community so I thought it is time I give back a little. After multiple Arduino projects the idea of having the Photon connected to the cloud and publishing data is another step forward, and an exciting one at that.
Added to this, and living in South Africa where we have one of the highest irradiance levels at 2000 kWh/m2, I thought to make an off grid, solar powered Photon with battery, and then update the State of Charge (%) and Battery Voltage (Volts) to ThingSpeak. Perhaps easier said then done, from the outset however with help from various posts here, some datasheets and some in depth tutorials I’ve got it all up and running.
To save power I have the Photon going into a deep sleep for 15 minutes (no issues with this despite many posts on it), and then waking to refresh the connection to the cloud and then send the latest data, after which going back to sleep - thanks @peekay123 for the work you’ve done here on current consumption in different modes (Deep Sleep uses very little energy to stay alive).
Below are some of the graphs from the last 2 days of operation; essentially charging with early morning sun, up to 91% and then overnight dropping to 85%. The charging in the morning happens quickly with a couple of hours of direct sun, and it seems there is much battery capacity to be used with additional sensors (I’m thinking of a lightning sensor (we got a lot of thunder storms) and some light level as well).
These graphs are part of the Matlab visualisation part of ThingSpeak. Matlab in the cloud… !
I’ll try to get some pics of the setup this evening and post these as well. I’m using a Photon, Powershield, a 145mm x 145mm solar cell and 3000 mAh battery.