Projects: Arduino-controlled Solar Charge Controller
So I was cruising Instructables again today. Once in a while, while weeding out the fairly boring crap like the thousand-and-one uses for Sugru or 3D printing an entire person, you find a real gem. While I am not a tree-hugger by any remote stretch of anybody’s imagination, I am a ham radio operator, and having a good source of DC power away from any kind of commercial hookup can be important, and I have been interested in solar and battery projects on-and-off for quite a while.
Pascal Foglietta from Sydney, Australia has put up an article–er, Instructable–about his Arduino-controlled solar battery charger controller that is a real work of art — not only the finished product itself (the protoboards, display, and enclosure are extremely professional-looking), but the documentation that goes along with it. The instructions, illustrations, and schematics makes this project better suited for a magazine like Make: Magazine or Nuts and Volts than an Instructables article. And while I’m getting sick of hearing about the Internet of Things (where everything you own needs to connect to everything else that you own), this project does a nice job of putting all of it’s data in human readable form on the Internet.
Here are the specifications of Pascal’s project (after the jump):
– Possibility to charge 6V, or 12V types batteries. (24V included in software but needs a small modification on the electronic side)
– Automatic detection of the type of battery connected.
– Push button to turn ON and OFF the output stage of the controller.
– Push button to display different information on the screen like total charge time, number of charging days, min and max battery voltages recorder, temperature, LUX values outside, maximum charging current and Watts as well as maximum output currents and Watts.
– All these values are saved to the EEPROM once a day when the ambient light goes down and are reloaded at start up.
– Possibility to erase the EEPROM and start with fresh readings, as well as possibility to delete the total charging time and days.
– The temperature of the battery is used in the software to reduce the charging values if it goes above 25° or raise them if it is lower than 25°.
– Informations are sent to the IoT (Internet of Things) once every 5 minutes to be able to keep an eye on how things are going when I am not at home. Check out my channel to see what it looks like and what informations are sent over by the controller. https://thingspeak.com/channels/17599
– Automatic disconnection of the load connected to protect the battery and prevent over-discharging.
– Bulk charge, followed by 1h of constant voltage charge followed by float charge.
– Maximum charging current supported by the controller is 10Amps, maximum output current is 20Amps.
– Maximum solar voltage input is 30V in this configuration.(limited by the 7805 maximum input voltage)
– Current consumption while on standby and not charging the battery is <10mA.
(Published from DFW, Texas)