MPPT Controllers
As I continue the learning curve, I'm finding the answers I get always lead to 2 more questions... funny how that is... I've been working backwards in developing my solar needs, going from panels t...
Forum Discussion
obiwancanoli wrote:
OK, this introduced another tangent to the process... what is the difference between 12V and 24V panels, and why should it matter?
The difference is voltage and size. 12 volt panels are made in lower volumes than higher voltage ones. 12 volt panels pretty much always cost more per watt.
Nominally 12 volt panels are in a range from 16 to 18 volts, with most at bout 17. Mine are 16.5.
I deliberately went with series/parallel to have a nominal input voltage of 33. The controller is a Blue Sky 3024 di. The amperage is derated at the higher voltage. It was, at 33 volts input pretty much "on the money" for 125% of panel output.
The higher the input voltage, the less efficient the MPPT controller is.
If I rewired to all parallel I might be able to do one extra panel.
At the time of purchase, Blue Sky had a 50 amp controller. It was bunches more expensive--but I rue the day that I decided on the 30 amp. They no longer make the 50 amp unit.
If I were starting from scratch, I'd move to a 48 volt battery bank.
