Solar Energy Control Panel "Solar Pi"


About This Project

This project is a control platform for my solar panels and power inverter. Goal is to monitor transformer and heatsink Tempuratures then take action by energizing the cooling fan in the power inverter and the windmill dumpload heatsinks.

(general introduction, overall experience with Cayenne, why did you create this project??)

I created this project out of a need to automate certain functions of the solar energy system. Since the algorithm used to monitor temps and control the inverter fan has been known to be flaky, I decided it was best to use Rpi3 and Cayenne. I have incorporated dumpload resistors on heatsinks to brake the windmill in high winds when the batteries are fully charged and these need cooling fans activated by Tempurature. This system will be installed in the Philippines and I can monitor it from the US.

What’s Connected

(Hardware, sensors, actuators, device model, WiFi, etc.)
Rpi3 Model B
8 relay actuator board for control functions
12" touchscreen for local browser use
6 ds18b20 stainless waterproof sensors
1 TSL2561 lux sensor
1 MCP3208 ADC for monitoring voltages thru the use of voltage dividers(True readings will come when voltage scaling is incorporated in Cayenne)

Triggers & Alerts

(Did you use the Triggers & Alerts feature?)

I used triggers to activate the cooling fans at certain temperature thresholds. Trigger on above certain temp then trigger off below certain temp.
Set a trigger to notify me when Rpi is offline and online.


(Did you use the Scheduling feature?)

I have a schedule set for sun up and sun down for off grid solar energy during the day, hope to use the lux sensor to do this without a schedule. I can also press a widget button on dashboard to manually reset inverter if it goes into alarm as well as 3 other buttons to control cooling fans manually. Will add later a widget to notify alarm status of battery bank monitoring system.

I will add more pics after this is installed on my solar energy system in the Philippines this coming January.

Thanks All for your help especially @bestes and @hightech.

Enjoy The View!

Dashboard Screenshots

(Paste screenshots of dashboard, triggers & alerts, Scheduling)

Photos of the Project

waterproof stainless ds18b20 sensors

image of touchscreen attached


It looks a bit…fragile.
There IS gonna be a more “robust” installation? :wink:

(I’m kidding with you :slight_smile: )


:smile: Yes I do plan on placing the mcp3208 on a pcb and in an enclosure with the relay board.I still need to work out an enclosure for the touchscreen tho. The Rpi is in a din rail I got on eBay and that will be screwed to the solar power baord.

more to come!


Ya, you are going for the 12-bit accuracy of the MCP3208
vs. the 10-bit accuracy of the MCP3008. Good.


just waiting on that update so I can set the scale and the server calculates the reading. funny thing now is the web browser shows 3.3v but the guage pointer is pointing almost to zero. I would think a full 3.3v would peg out the gauge, hmmmm pesty bugs, maybe some pesticide :wink:


In the HTML web browser dashboard, you can now set gauge colors, and add several ranges- setting upper and lower limits. You should check that out- :wink:
It seems that the HTML Dashboard
has more functionality
than the iOS or Android app-


I have checked out the gauge range options the other day and it’s ok. I’m tempted to give up on ios for awhile, just too BUGGY. Some widgets refuse to add but show up on the browser anyway and don’t function. I’m having trouble adding some widgets on the browser as well. I guess patience and time will bring a better Cayenne. I have submitted bugs/issues but I think the guys are real busy with the next update. Your very helpful and I appreciate that, Thanks


@bestes @hightech
Here is an update. Project is now in service monitoring inverter process. Some functions are not tied in yet such as the arduino mega based PLC(the black box with the wifi antenna) to monitor voltages such as batteries, solar panels, charge controller output and inverter power output. This project is located in the Philippines. I installed it this month 1/2017 on vacation, working vacation, but loved having more time to concentrate on it.


Wow, that looks awesome!


Thanks @adam!

Now all I need is to find someone willing to write code for my arduino PLC for a buck. I am the extreme dummy for coding. I can figure out and build most anything but the math needed for coding to monitor voltages and alarm and status inputs escapes me.


It’s not too bad, just seems harder than it is. If you make another post with what devices you are using and what you want to do we can try to help!




That looks so awesome! You have a mini command center. Comes with a security camera? :slight_smile:

Keep us updated with your progress please! @vmnguyen might be interested in featuring your project in one of our upcoming newsletters or doing a blog post.

And of course let us know if you need any help with the code!