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This project exists because there is so much day time power being produced in Australia from small scale roof top solar systems that most days the wholesale price is negative meaning energy retailers are paid if their customers use power from the grid.
Those with home battery systems are in a unique position to be able to soak up free power between 11am and 2pm and then use it at other times of the day, or get a higher price for exports to the grid in the evening which will reduce the pay off time for their battery systems.
Firstly you will need a system capable of running python scripts, however all development and testing has been done on Debian 13/Trixie but should work on other Linux based operating systems. No idea if a Windows environment will work at all.
The astral library is needed to calculate when the solar system stops being productive. This will vary depending on both how westerly your panels face and their tilt. This tends to occur when the sun drops below 20-25 degrees above the horizon.
apt install python3-astral
git clone https://github.com/evilbunny2008/FreePowerMaximiser.git
cp FreePowerMaximiser/fpm.conf /etc/
chown root:root /etc/fpm.conf
chmod 600 /etc/fpm.conf
Using your favourite editor, edit the config file.
nano /etc/fpm.conf
For Solcast forecasts you need to sign up for an account and then paste the account API key in the appropriate place in the config file, along with the site ID(s) for your array(s).
For forecast.solar forecasts you just need to edit the config file with you latitude and longitude as well as the vertical tilt of your array(s), the azimuth(s) and the maximum size of your array(s).
It might be because Solcast is an Australian headquartered company and do best in the region but I've noticed their forecasts to be more accurate for both my solar systems than forecast.solar forecasts.
You now need to go into the v1 Fox ESS cloud dash board. Once logged in click on picture of a person at the top right of the web page and then click on "API Management".
Finally click on "Generate API key" and copy the generated key into the fpm.conf file.
chown -r root:root FreePowerMaximiser
chmod 700 FreePowerMaximiser/bin/fpm.py
Hopefully by now you have everything you need to start maximising the free power and higher FiT in the evenings, all you need to do now is call the script as follows.
FreePowerMaximiser/bin/fpm.py
The power plan we are on now is simply unbelievably good value for houses with battery systems.
The daily connection fee is $2.07 per day, but if you don't import power from the grid between 6pm and 8pm at night you get a discount of $1/day.
The plan does time of use billing with off peak being 11am to 2pm every day of the year, peak between 4pm and 11pm and shoulder the rest of the time.
If you export between 4pm and 9pm you get 6c per kWhr, if you export between 6pm and 8pm you get a 15c FiT for the first 10kWhrs.
If theory works out in practice we may end up with a power bill less than $100/quarter.
I can't remember when we would have had a power bill that low!