LM317T Voltage Regulator with Pass Transistor

The controller is regulating battery voltage now. Target voltage has been set at 14.2 volts. The display LED shows a PWM simulation when target battery voltage is reached (this doesn't show up too well on the video), and a series of flashes when it's below target voltage. 1 flash for 11 volts, 2 for 12 volts, 3 for 13 volts etc. It also shows a series of rapid flashes if voltage drops below 10.5 volts. The LED can be turned off altogether if desired to save power. With the LED turned off, the controller takes very little current - about 0.5 milliamps, that's just 500 microamps! Future developments will include detection of excessively long cables between the battery and the controller or excessive current flow. Also voltage measurements will be more discriminating to get a more precise, more stable feedback control. Part of 'designing a solar charge controller' at www.256.co.uk



http://www.youtube.com/watch?v=UPVzB2HY-Dg&hl=en