flippineck
- Sep 8, 2013
- 358
- Joined
- Sep 8, 2013
- Messages
- 358
I have a solar storage setup composed of six 80 watt panels, a cheap ebay regulator, and a 12V leisure battery hooked up to a 12VDC--->240VAC inverter.
I've connected all six panels together in parralel. The voltage output from the array varies from near zero (16 millivolts) in the dead of night, to around 21 volts in full direct midday sun.
At dawn and dusk, there is a fairly extended period where the voltage output from the panels transitions through the 12V point.
The regulator will only start charging the battery when the input voltage rises above 12V.
What I'd like to do, is try connecting two sets of three panels each in parralel, to give two seperate strings which each vary 0-21V. And then, depending on the voltage, connect the strings together either in series (to give a higher voltage when the sun is low) or parralel (keep the voltage down but take advantage of extra current when the sun is high).
I've figured out how I could do this pretty easily using a relay with two sets of ganged contacts and some creative relay wiring - but how would I accomplish automatic control?
I was vaguely thinking about placing two high value resistors across the output of one string of panels to form a potential divider, then feeding the mid point of the divider onto the base of a transistor, which would then be used to switch the relay coil. Or, maybe, some form of operational amplifier based comparator.
My design skills aren't sufficient to come up with a workable circuit though. Does anyone know of an existing design, or could suggest a basic workable schematic?
I've connected all six panels together in parralel. The voltage output from the array varies from near zero (16 millivolts) in the dead of night, to around 21 volts in full direct midday sun.
At dawn and dusk, there is a fairly extended period where the voltage output from the panels transitions through the 12V point.
The regulator will only start charging the battery when the input voltage rises above 12V.
What I'd like to do, is try connecting two sets of three panels each in parralel, to give two seperate strings which each vary 0-21V. And then, depending on the voltage, connect the strings together either in series (to give a higher voltage when the sun is low) or parralel (keep the voltage down but take advantage of extra current when the sun is high).
I've figured out how I could do this pretty easily using a relay with two sets of ganged contacts and some creative relay wiring - but how would I accomplish automatic control?
I was vaguely thinking about placing two high value resistors across the output of one string of panels to form a potential divider, then feeding the mid point of the divider onto the base of a transistor, which would then be used to switch the relay coil. Or, maybe, some form of operational amplifier based comparator.
My design skills aren't sufficient to come up with a workable circuit though. Does anyone know of an existing design, or could suggest a basic workable schematic?