Arduino/Spark based solar power controller for micro-grids
Arduino/Spark based solar power controller for micro-grids
The simple and inexpensive power savings solution has arrived. Go off grid by using solar energy with your home, cabin, camp, RV, boat!
The simple and inexpensive power savings solution has arrived. Go off grid by using solar energy with your home, cabin, camp, RV, boat! Read more
About this project
If you missed the funding period please click here: www.UNplug.energy
As featured on:
Introducing UNplug, a simple, inexpensive, and fully-automatic power savings solution.
Did you know that there are over 100 million refrigerators, internet modems, and laptops all running on fossil fuels in the United States alone? Every year, that adds 33 billion pounds of CO2 to our atmosphere, and is equal to the total CO2 produced by four coal power plants! Here is a link to the greenhouse gas emissions calculator if you want to check this yourself.
We are all still contributing to the problem: CO2 pollution is the biggest driver of climate change. This year was both the coldest and hottest the US has ever experienced!
Don’t take our word for it, read the US government's report, “THE PRESIDENT'S PLAN TO CUT CARBON POLLUTION IN AMERICA” at www.whitehouse.gov/climate-change
Introducing… UNplug: A cleaner, independent and reliable solution.…
But how can that work?
Contrary to a recent FOX News story, the USA does get more sun than Germany! German solar power plants produced in 2012 a world record 22 gigawatts of electricity - equal to 20 nuclear power stations running at full capacity. So, If you can see the sun, feel its warmth, then there is power you can use too!
Not only are the sun’s rays good for your skin (in moderation), but it is also... Great to power your home, cabin, boat, camp and RV; Providing emergency backup power; and Saves dollars on your electricity bill.
The solution begins with getting your refrigerator and a few other essential items off the grid during sunshine hours.
Let me ask a question:
How can we save money, and have a quick and positive impact on the environment?
Here’s the answer:
By using the greenest energy source there is… solar. No moving parts, the power is just absorbed through solar panels. With this free energy, you turn your power needs “off the grid” during the most critical "peak" times in a day. Between 10am and 6pm when energy costs are the highest. At night UNplug automatically switches you back to the electricity grid.
To reiterate… You automatically UNplug from the grid during the day and re-plug at night.
You’re Protected! If there’s an outage, and you can’t switch back to the grid, this is when the batteries take over. Unplug provides automatic uninterruptible power (UPS) with built-in surge protection.
You can protect your home security system from losing power and keep all your essential home automation systems in operation:
- Landline or IP-Phone
- Lights Radio/Cell Phone
- Smoke Detector
- Surveillance Cam
The way we use power daily has and is constantly changing. UNplug is revolutionary because it gives you your OWN power grid for your home.
The electricity grid obviously isn’t perfect. If it was, we wouldn’t have any outages, and power would be completely clean. UNplug gives you the stability, protection, and peace of mind you need.
Imagine a few items in your household that can be pulled off the grid during the day. Almost everyone owns theses items:
- PC / Laptop / TV / Stereo
- Internet Modem / USB Chargers / Power Supplies
Just the refrigerator alone consumes between 40W - 160W on average, that means 1-4kWh per day. We are a power hungry civilisation and we have to offset our impact on the global climate, besides, when there’s sunlight outside, shouldn’t we be using that power?
It was during the stormy winter in 2011 that my family and I suffered a black-out, and my power was out for days. This started me thinking: if I only had some independent power source available. Maybe I would not have lost all my food in the fridge.
Then, the next morning I went outside, saw the sun, and thought… with this much free solar power around us, how can I make it work for me?
A year later I had a working prototype in my garage, and a solar panel mounted to the roof of my garage. Excited, I ran a long wire from my garage to the house. The images below show on the left my setup, and two of my tester installations. In case you are wondering: you can mix solar panels of different brands and types as long as they have the same voltage.
And Voila! it worked! I was amazed, stunned, thrilled… and knew I had found my solution! I took my fridge off the grid!, and I now knew I NEEDED to help everyone else do it too!
And it was at this point… the point of success... that my creation was born… and would be known to the world as…
I kept revising, optimising, and improving my designs, and in February of 2014 I finally had a first batch of the Printed Circuit Boards (PCB) ordered. The first version was developed with great help of my friend at Athens Consulting. It needed a LCD display and menu buttons to interact with the user. It was a costly, complicated to assemble, and needed an expensive custom made enclosure. After I had a long conversation about the product with a college, I realized that with the introduction of WiFi the on-board controls and display weren't even necessary. With web access and mobile apps, I could deliver a better user experience with more information and easier control.
As evolution of the product progressed, UNplug shrank in size, and can now (in its optional case) fit safely in a small space in my kitchen with no exposed wires. Now the whole family, even the pets, are as safe as they are around any appliance.
Now that UNplug has been refined and optimized, It is very simple to assemble. All you need is a screwdriver and the easy to follow instructions (printed and online video tutorial link are included)!
The picture above shows the two tiny microcontrollers (left top corner) (one is included, depending on which model you choose) that plug into the PCB (electronics board) – which goes into the green safety enclosure next to it. The rest are different types of cables for connecting 120V, solar panels (right most), batteries, inverter and charge controller (along the bottom).
You might say UNplug is the “heart” and “brains” of your home’s central nervous system, but just like your body, it relies on other components: the eyes (solar energy), Stomach (batteries), legs (inverter), nerves and veins (Wires).
A complete UNplug system requires solar panels, a power inverter, a solar controller, and batteries. To make installation as reliable, simple and easy as possible, we’ve assembled (and will continually update) a list of tested and works-great-with-UNplug “body parts”. (UNplug is VERY versatile, and you’re free to find and use any parts for your system you want, we just want to make it as easy for you as possible.
So if you follow simple instructions - similar to those known from a Swedish furniture brand - you’ll get your system setup and operating the way you want it.
Electricity is dangerous, and if you aren’t completely careful you could hurt yourself. Please be sure to have a licensed electrician on hand during your installation, and follow ALL instructions to the letter. If you plan to conect this to your breaker box be sure to follow local code requirements. We can not be responsible for your actions, just our products. PLEASE BE SAFE!
Note: UNplug will receive UL certification once funding is reached!
To clarify this: you can just plug the cable going to the ‘Power Grid’ (in the schematics drawing above) into the wall socket. How to UNplug your fridge is shown below:
To keep the cost of UNplug as low as possible we offer two options:
- You know how to use a screwdriver and can connect all of your wires to UNplug yourself.
- We assemble and send you a complete UNplug ready to plug-in.
With one choice above UNplug will be ready to go… however, you will still need to purchase a few off-the-shelf parts below.
To make this part of the process as easy for you as possible, we will provide a web link to the list of verified products, and will update the list as we welcome companies to submit their products for verification.
To build a complete system, these items, in addition to UNplug, are required:
- Power Inverter 12V or 24V with at least 1200W continuous power ($90 - $250). An inverter, is an electronic device or circuitry that changes direct current (DC) to alternating current (AC). AC is used for all household appliances and DC is stored in batteries and produced by solar panels. Here is a link to a Power Inverter FAQ that might be able to answer further questions.
- Batteries that add up to 12V or 24V with a minimum capacity of 30AH ($65 - $200). A sealed battery or maintenance free battery, is a type of lead-acid rechargeable battery. They are required because they store the energy that can be used during a blackout or if the system is operated off-grid.
- Solar charge controller 12V or 24V with at least 6A ($30 - $95). A charge controller limits the rate at which electric current is added to the batteries. It prevents overcharging and may protect against overvoltage, which can reduce battery performance or lifespan, and may pose a safety risk.
- Solar panels with combined power rating of at least 250W ($200- $380). A Solar panel refers to a photovoltaic (PV) module and is a packaged, connected assembly of solar cells. Solar panels can be used as a component of a larger PV system to generate and supply electricity in commercial and residential applications. Each module is rated by its DC output power under standard test conditions (STC), and typically ranges from 100 to 320 watts. PV modules convert sunlight into DC power.
In total, the additional parts above should cost around $570, and are all you’ll need to make your UNplug fully operational!
What's best about UNplug is that it is completely ready for the future! As your needs grow, you can add to your system, and if new and better ways to generate power are introduced, UNplug will be ready to use them.
Due to the modular design of UNplug each component can be updated independently. This is just your starting point to ongoing power self-sufficiency.
For example you can:
- Add more solar panels if you extend the usage in your home
- Add more batteries
- Transition from lead acid to LiFePO4 or whatever technology comes after
- Replace the inverter by a more more efficient or more powerful unit
- Replace the universal socket microcontroller with a newer version supporting bluetooth, cellular network or the next big thing
- Receive automatic firmware updates (WiFi) that let you integrate with the latest home automation tools
We offer two main configuration (EASY vs. SMART) options. These include the circuit board and one of the two microprocessor options:
This is your EASY and inexpensive solution. Plug-in and forget about it. This version is completely self-sufficient and consumes less power.
It’s simple. If you want the magic to happen invisibly, you can choose the EASY version. This is ideal if your main use is on a RV, boat or a cabin where there is no WiFi available. All optional configuration parameters are accessible via a USB connection.
If you decide as some point in the future you want to hook into home automation you can easily upgrade to the SMART UNplug for a nominal fee.
The microcontroller is manufactured by US based company Folger Technologies
If your system is permanently mounted in your home, the SMART configuration is ideal. All settings will be accessible via direct USB connect or online through wifi using an app on your smartphone, computer or tablet. UNplug also easily integrates with internet of things (IoT). The IoT is the network of physical objects or "things" embedded with electronics, software, sensors and connectivity to enable it to exchange data with the user or other connected devices. All controllable through your computer and/or smartphone/tablet.
- PV panel input voltage <50VDC OC, 50A max.
- AC terminals: 10A @ 120VAC, 50/60Hz
- Charge controller terminal 50A,12/24V
- Inverter terminal 50A, 12/24V
- Battery capacity range 10-10000AH, 12/24V
- Internal power supply max. 24V/08.A (20W) - important if you plan to use the UPS functionality. The used inverter should not exceed 0.8A in standby.
- Temperature range -20 … +60C
- Wifi 802.11b/g support (if Spark Core is used)
- Self power consumption: 1.5 Watt
- Dimensions: 170.94 x 120.90 x 55.12 mm / 6.73 x 4.76 x 2.17 in.
- Weight: around 880g or about 2 lbs
- UL certification is part of the funding and is scheduled for August 2015
UNplug is doing load switching between the solar power and main power to optimize battery life and maximize solar energy usage. It also offers a standby UPS mode to provide surge protection and emergency battery backup 24/7.
The run-time for the battery-operated UPS mode depends on the type and size of the batteries, rate of discharge, and the efficiency of the inverter. A wide variety of inverters and battery sizes can be combined to provide you with the optimal system for your needs.
To start, you can setup a minimal system with 12V, 10AH and go up to 24V, 10000AH using common SLA or even LiFePO4 batteries. Then, as your need change, you can add more.
The controller has USB/Wifi connection and can be setup via PC or mobile device, and with its online dashboard you can monitor your energy usage right from your phone.
UNplug also as a buzzer to give an acoustical warning. If the unit gets too hot, the batteries are low on charge or the electrical current is too high it will alert you on your mobile device and you’ll hear the warning signal if you are nearby. If any of those mentioned conditions will be reached the unit will switch back to the electricity grid and deactivate until the user has reset the unit manually.
UNplug’s online dashboard reports the following information about your usage, and the health of your system:
- current watts generated and consumed
- battery charge (SOC) and temperature
- black-out detect
- peak solar and output power
- $ and CO2 savings
- lifetime kWh counter, total runtime
- graphs plotting the performance over the last 30 days
- analysis of over- or under-usage
- status messages
- predicted runtime for battery
Currently, the web-based dashboard looks like this and will soon also be available in a mobile device app.
As an example here is a snapshot of my system with months of accumulated energy:
The UNplug firmware will be pre-installed onto the processors so each unit is ready right out of the box. But you can even go “fully hacker friendly” and download and compile your own programs. There is an Arduino and Spark compatible C-library that allows you to program your own functionality and go be beyond the intended use. There are two interfaces (Serial and I2C) to wire connect the unit to other hardware like the Raspberry Pi, etc.
You can find the Arduino/Spark libraries and pinouts in the GitHub repository.
By using the Spark microcontroller the unit can even be hooked into If This Then That (IFTTT) - a service that lets you create powerful connections with one simple statement. Check them out, you are going to love the easy to use “recipes”.
As an example these recipes can send you a notification on your iOS or Android device or send out an email. The states you can monitor include:
- connect/disconnect from Wifi
- electricity grid lost power
- a battery discharge threshold has been reached
- a fuse has been triggered to protect for over current
- the inverter has failed
- voltage too high
I have gone from breadboard proof-of-concept into actually manufacturing a small run of PCBs. Most of them are at friends houses who help beta-testing the system in combination with various inverters and charge controllers. Further details can be found on the GitHub repository.
Below you can see the rev 2 PCB:
Here is the list of items explaining the main components:
- 1: 24VDC supply for external hardware with a max draw of 20 Watt
- 2: Header pins to communicate with other hardware: Serial1 and I2C
- 3: Slot for a Spark Core or Arduino Nano. The USB connector of the Spark or Arduino is accessible through an opening in the enclosure so you can easily connect to a USB cable during operation.
- 4: Buzzer for acoustical warning
- 5: Temperature sensor
- 6: 24V transformer
- 7: Heavy duty 6 AWG terminals to connect to solar panel, charge controller, battery, and inverter
- 8: Heavy duty relay to switch between the two power sources which are connected at terminals #10. Switchover delay 25ms.
- 9: Power mosfet bank to switch up to 50A at 30VDC
- 10: Terminals for 10A at 120VAC
It is called "third industrial revolution" and seems to be soaring in the energy sector since a few years. Here are some interesting quotes I have found:
- Imagine hundreds of millions of people producing their own green energy in their homes, offices, and factories, and sharing it with each other in an "energy internet," just like we now create and share information online -- Jeremy Rifkin, Third Industrial Revolution, 2013
- "Centralized generation is also inefficient because approximately 15% of power transmitted today is lost as it travels" -- Wanda K. Reder, IEEE Smart Grid Taskforce, 2013
- "Microgrids have obvious benefits when the grid has gone down" -- Jeff St. John , https://www.greentechmedia.com, 2012
- “We’ve got a lot of work to do if we’re going to survive on this Earth, but most of it needs to be done close to home. Small, not big: dispersed, not centralized.” -- Bill McKibben, 2010
Lastly, we would like to thank you for taking the time to check out UNplug. We hope that you will back us and share this project!
Sustainability has become my passion and I hope it sparked the desire in you to become part of the green energy movement. I cant wait to see us all using free energy!
Risks and challenges
Anytime you manufacture anything there will be risks. Most often the risks are related to part supply and delivery time. However, we are confident that we will deliver a high quality product to all our backers.
Currently the production facility for the PCBs, enclosures and electronics suppliers have been selected. All partners are established companies in North America with long track records of delivering high quality products.Learn about accountability on Kickstarter
This version currently supports only 120V - but the plan is to create a version supporting 230V as well. Timeframe will be end of this year.
No, you can hook up 2 fridges to one Unplug unit but you need a bigger inverter than the one that I list as an example. I suggest an inverter with at least 2000 Watt
Yes, you can add more panels. You just have to make sure they have the same voltage (Voc) or the same number of individual cells; these are either 60 or 72 for 24V (or 30 and 36 for 12V)
Can UNplug be configured to draw down the batteries by a certain percentage before switching to grid power? For example, when solar power is lost, draw down batteries by 20% before switching to grid.
Yes it can, per default this threshold is set to 10% to maximize battery lifespan.
SOC (State of charge) is done via coulomb counting using a shunt. But it also monitors the voltage and has settings for low voltage disconnect (LVD).
Are there any extra pieces of equipment i would need to buy for the Burning Man package. I also am wondering what your best guess is for how long your equipment will last?
The package is complete, no other parts are needed. (If you have a generator as well then it simply plugs into the generator and all load is plugged into the outlet of UNplug.)
The runtime depends heavily on the usage. The battery has a capacity of 840Wh that means if you draw 100W continuously it will run about 8 hours at night.
At daytime UNplug recharges the batteries and the extra energy can be used. If you plan to have light use 120V LED bulbs. Take a look at my blog post about last years solar statistics of my camp: http://solar-trap.com/…
If you need more capacity you can simply add more batteries of the same type in parallel.
Can UNplug be used in a home connected to the grid but take the refrigerator totally off the grid instead of using it as a backup. Maybe a different way of asking is will the grid be used as little as possible in your setup with the grid attached?
Yes, the behavior of grid usage can be configured via settings. Per default UNplug only discharged 10% if grid power is available to maximize lifespan of the batteries.
Support this project
- (30 days)