Inverter Breadboard—monitoring—battery connections—system diagram

System Current monitor and battery voltage meters

4 AWG wire for battery interconnections

Morningstar solar regulator




The low voltage detect breadboard will be replaced with the microcontroller that will monitor solar panel charge current, open circuit voltage, battery voltage and current draw from the battery system. This data will be recorded and transferred to my desktop computer using a zigbee wireless radio system. The performance information and software will be available on this web site.


In addition to the larger inverter, a second 400 watt inverter has been added to just power the TV and satellite receiver. This will reduce the standby current. A future version of the system will replace the Morningstar regulator with an MPPT controller.


The Arduino microcontroller will be used for monitoring and will be programmed using a modified form of C++ developed specifically for the Arduino.


The solar panel installation is clearly not a traditional one inasmuch as I have a lot of large shade trees that I have had to accommodate. This translates to the clear need for an articulating mount that will be located where the shade is marginalized or eliminated for the major part of my solar day. I now feel sure that this will be a project that is required if I am to have the output I want.


Please note the reference shown on the solar data page concerning the hookup of batteries in parallel. Since this picture was taken I have modified the hook up. As note in the system diagram, I have also installed a relay and an amp meter to measure the solar panel output (part of my manual data collection efforts). The relay is shown as a single pole but it is in reality a double pole unit with a momentary push button for activation. The normally closed contact routes current from the Morningstar regulator to the batteries.


The next phase of the power system will be to incorporate the wind turbine and to include a “dump load” so that the batteries will not be overcharged. The microcontroller will monitor charge current from both the solar panels and the wind turbine.


When the wind turbine is operational I expect to have sufficient charging capacity to power the small window air conditioner in the bedroom.


Lessons learned  -  June  2008 :


While the solar system was easy to build, the output has not been as much as I would have liked and is insufficient to run the system. This leads to the observation that a wind turbine would have been a better choice for a first project. While it is clear that a combination system (solar and wind) is the optimal configuration, I have come to believe that a wind turbine is more bang for the buck then a solar system. In the cost per watt analysis, wind beats solar without any difficulty.


Having said that, I will as part of the future system expansion, build a much larger wind turbine that is a three phase AC system, rather than the DC system, using the Ametek motor that is referenced in the wind turbine section. The AC system will require me to wind my own coils and use rare earth magnets. While there are numerous designs on the net, the one I have chosen was designed by Hugh Piggott He is really the master at building wind turbines and has a long history of successful implementations.


It is also time to consider a permanent location for the system and to update the interface to the house. I will add remote controls for each of the modified sine wave inverters (three are planned—one to run the TV in the den, one to run the air conditioner in the bedroom, and one to run the computers in my office). In addition I will add one true sine wave inverter that will run the laser printers, the microwave and the wireless network. I also have to get to work on doing the code for the PLC so I can effectively monitor the system from my laptop.



Revised on 5/4/08

Fuse block — to be replaced with a breaker box when the second inverter is installed

Digital voltage meter and 12 VDC source for work light

Herb & Barbara our interests and family