2008 2500 170" EXT
I believe I have misspoke or erred previously.Are you saying one would need separate controllers for bifacial panels to handle the voltage difference from retracted panels? I thought wiring panels in parallel to a single controller could handle the voltage difference from a shaded panel. If parallel wiring won't handle the voltage difference I can understand why normal lower panels must be shut off when retracted. Including a shut-off switch for the lower panels will complicate the installation a bit.
I was thinking of a four panel system with each layer of two panels in series and then the series pairs paralleled to the controller. Think I might need to get smarter on solar installations.
One MPPT controller can effectively and efficiently work for bifacial arrays and when they are retracted. The upper and lower arrays would need to be wired in series, where their different voltages add to and compliment each other.
I'd also wire the array's panels in series, as I'm an advocate of higher voltage.
One third down the page:
Connecting Voltage Sources Together
Ideal voltage sources can be connected together in both parallel or series the same as for any circuit element. Series voltages add together while parallel voltages have the same value. Note that unequal ideal voltage sources cannot be connected directly together in parallel.
Voltage Source in Parallel
While not best practice for circuit analysis, ideal voltage sources can be connected in parallel provided they are of the same voltage value. Here in this example, two 10 volt voltage source are combined to produce 10 volts between terminals A and B. Ideally, there would be just one single voltage source of 10 volts given between terminals A and B.
What is not allowed or is not best practice, is connecting together ideal voltage sources that have different voltage values as shown, or are short-circuited by an external closed loop or branch.
Badly Connected Voltage Sources
However, when dealing with circuit analysis, voltage sources of different values can be used providing there are other circuit elements in between them to comply with Kirchoff’s Voltage Law, KVL.
Unlike parallel connected voltage sources, ideal voltage sources of different values can be connected together in series to form a single voltage source whose output will be the algebraic addition or subtraction of the voltages used. Their connection can be as: series-aiding or series-opposing voltages as shown.
Voltage Source in Series
Series aiding voltage sources are series connected sources with their polarities connected so that the plus terminal of one is connected to the negative terminal of the next allowing current to flow in the same direction. In the example above, the two voltages of 10V and 5V of the first circuit can be added, for a VS of 10 + 5 = 15V. So the voltage across terminals A and B is 15 volts.
Series opposing voltage sources are series connected sources which have their polarities connected so that the plus terminal or the negative terminals are connected together as shown in the second circuit above. The net result is that the voltages are subtracted from each other. Then the two voltages of 10V and 5V of the second circuit are subtracted with the smaller voltage subtracted from the larger voltage. Resulting in a VS of 10 – 5 = 5V.
The polarity across terminals A and B is determined by the larger polarity of the voltage sources, in this example terminal A is positive and terminal B is negative resulting in +5 volts. If the series-opposing voltages are equal, the net voltage across A and B will be zero as one voltage balances out the other. Also any currents (I) will also be zero, as without any voltage source, current can not flow.
Anyone see issue here? Do the watts also stack up and the net result is more input amperage?