July and the beginning of August has been low on the radio activities. Mostly because of traveling (and the preparations). Now I should be getting back to some radio.
But first, solar power:
Today I made a small improvement of my solar power system in the shack.
The old system had just 2x130W panels (designed for 12V systems).
Those are now replaced with 4x100W panels in series. How will this work with the 20A MPPT charge controller I am using? We shall see. The absolute peak voltage of the panels is less than the 100V open circuit the controller can handle, so having 4 panels in series, providing less than this is quite acceptable.
The current/total power handling is another matter. The peak power of the panels is 400W. This is only achieved with the panels fully illuminated with direct sunlight, at right angles to. While this happens sometimes I am hoping the controller will be able to handle it.
The controller spec says that it will limit the charge current to 20A, so I hope it will work nicely.
The lower light charge current with the 2x130W panels was quite low, down to about 300mA which cannot get the batteries fully charged every day. With the 4x100W in series, this looks more promising, but as I have just made the modification, I will need to check this in the coming days, so after some more tests I will write another post on this.
I do have another of the MPPT controllers, and I have the idea to mount some other solar panels connected to this controller, for boosting the possible charge power.
For this I want to use two or three sets of 4x50W panels, mounted for "seeing the sun in different directions:
- One set on the South wall of the out-house, for winter/low angle sunlight.
- one at the West wall of the main house, for catching some late afternoon and evening light.
- maybe one at the other end of the garden, for catching some morning light.
While this adds up to a total of 600W peak power, I think that this will never be reached from this system, as the optimum angles for the 3 panel systems are too different. I suspect that it will end up providing max 300W for charging the shack battery.
Even in the winter this system should be able to power a minimum set of radios for some monitoring, but I do suspect that in midwinter it will probably need some assistance from mains power charging, if I want to operate more radios. We shall see.
