Off Grid Project

@gmszone Hi John. I will probably be able to provide help as you build out your system, I have a 7.2kWh LiFePO4 battery bank, all victron equipment, battery monitor, 3,000 watt inverter/120 amp charger, 70 amp MPPT, 2x3x190Watt panels, a Color Control GX main control panel and a Digital Multi Control (for managing 30A campground power). I designed and built it all myself so have recent first hand knowledge. Are you using the Venus software on the Pi?

@zander Actually the tracker is running on a python program my brother and I wrote. Positioning of the array is attained by making use of a library. We pass in the geo location, date, and time and get the current altitude and asimuth. Then move the array slightly beyond these points. The net result of this approach is that the array only moves twice an hour. I have a small touch screen display, keyboard and mouse attached also. My reason for building a new controller is three fold. First to simplify the components. Second, include some missing safety features. Third, expand my capabilities!

@gmszone My panels are on the roof of my RV and I did not bother with the expense (each one more than the price of the panel) of trackers. As well, that kind of tracker only adjusts one way. I do have hardware to raise them but by going to the web site where you input all your variables it quickly became apparent that in the summer laying them flat gave more watts due to the northing (I am  above 49) In the winter I do tilt them but it is interesting to see the results at 60 degrees of tilt versus say 15. The annual yield is very close, but big differences based on time of year.

I assume you have dual axis tilting and probably much bigger panels than me.

@gmszone One key point, a Pi PICO is NOT a computer, it's a micro controller or MCU unlike a Pi 4 that is an MPU. That might make some things difficult to do. The software in my system monitor is Linux based and can be run on a Raspbery Pi but I chose the commercial unit to save time.

@zander I am trying to avoid a monitor. I hope using an lcd display will provide all the details that I currently view on the current controler. All of the current configuration values are hard coded with the exception of using the library for solar positioning.

I was hopeful that the solar positioning data can be condensed into an array where the only keys would be day of year and hour of the day. I have been checking performance and moving the solar array once per hour should work great.

@zander Regarding the efficiency difference I am getting from the dual axis design. From what I can tell it looks like about 50% more annually. Pointing at the sun from sunrise to sunset every day of the year adds up! We live one hour east of Stockton CA. On a typical 100 degree day mid summer this 2600 watt array will run the house, AC, and recharge the batteries from 80% back to 100% by around 4 pm.

@gmszone I only have 1,149W of solar and don't attempt AC but we do have a modern residential fridge that uses about 1.5kWh per day. Even though I live in Canada one of the small towns here registered a recorded breaking temperature of 116F/46.6C a couple of years ago and we regularly get over 30C/86F even 5 minutes from the ocean.

I live in an RV and am connected to shore power so I can use the AC on the 2nd power leg while the inverter runs everything else.

Quite a bit hotter where you are.

Are you familiar with the solar calculator HERE, it will tell you what you can expect historically. It's what I used when I was sizing my system and expecting to spend 6 months of the year in the winter in the US south west. Covid and the increasing violence in the US ended those plans.

@zander That's too bad to hear regarding the crime in the US. We have a nice little property out in the Foothills of the San Andreas mountains. If you wanted to visit California, you're welcome!

@gmszone Appreciate the invite but at soon to be 81 the cost of medical insurance in the USA is in excess of $10,000. I am going to change directions and go back to the safe harbour of northern Ontario, selling the RV and truck and buying a small car plus Side by Side ATV and exploring the area plus building some electronics, maybe for the model train folks as well.

@zander May God bless you and your travels!

@gmszone Thank you. I would love to see some pictures of your installation and your environment if it's not too much to ask. My heart is with you and all the other off grid folks who are taking on life and winning but pictures are all I can share in now.