Suntrunks: Solar Power To Go
Suntrunks: Solar Power To Go
Suntrunks are completely Self-Contained Portable Solar Electric Power Systems for Remote or Emergency Power Needs
Suntrunks are completely Self-Contained Portable Solar Electric Power Systems for Remote or Emergency Power Needs Read more
About this project
Suntrunks Project Summary: Suntrunks are completely self-contained solar power systems that have all components built into a rugged transportable case or trunk that can be set up and operating in 5 minutes. They provide USB and 12 VDC outlets for small loads and 120VAC power for larger loads. The solar panels recharge internal batteries each day and then the units can provide power even at night. I’ve built operating prototypes in 6 different sizes and they work very well. I need your help to rigorously test the units and to construct multiple second generation units to incorporate improvements and reduce production costs. These solar power systems are a viable supplement to batteries or fuel driven generators when you have emergency or remote power needs.
Hi. I’m John Wennstrom and I’ve been involved with solar energy for a long time. Way back in 1977 while in college I did my Masters Thesis on a solar photovoltaic system that I had built and tested.
Today, I believe that solar energy can do many more things for people in remote areas and especially in disaster recovery situations.
The “Suntrunk” idea came to me in the days following the January 2010 Haiti earthquake. The news reports showed the terrible physical and human devastation. The reports also told of the great need for food, water and medical supplies and the total lack of any power sources. No electricity or gasoline or oil. It was many weeks or even months before generators and fuel supplies became available.
I also noticed that for the most part, during the day the sun was shining. My vision became to invent and package a complete solar system about the size of a suitcase or a trunk that could be transported easily and set up quickly to capture a day’s sunlight and make electricity available for many of the basic loads needed for the relief efforts.
A more recent example was Hurricane Sandy that hit the US last year. Millions of people were without electricity and gasoline. In events like these, small power sources can run phones, laptops, radios and TVs. And they can provide lighting at night.
A small solar electric power supply can make a huge difference to people just trying to get by day by day.
The first Suntrunk was in a hand made wooden box about the size of a very large cooler. It had three 30 watt solar panels that would fold out and lock in place, a heavy lead-acid battery, an inverter to provide 120 Vac power and the controls to make everything work as a complete package.
And It Worked!
With just a days worth of solar input I could run lights, fans, power tools, radios.I could run or charge phones and laptops even at night by drawing off of the battery. But it was hard to build, weighed over 150 pounds and was not really rugged enough to be the transportable or useful power supply I had envisioned.
My vision has expanded from the initial idea.Now that I knew it would work, I though of the other uses for such a system. Developing nations with limited electric grids or no utility power could use portable stations for many things. Solar energy could reduce or replace the use of candles and kerosene for lighting.
These systems could meet many of these very small loads. But why stop with just the smallest loads. There are many mini solar chargers on the market that can provide small lighting or small battery recharging needs.
Solar can and should be doing more.
What about power tools like drills, saws, electric screwdrivers? What about pumping water with a small pump? What about running a small refrigerator for vaccines or other perishables? What about lighting a whole class room for several hours during the night?
Solar can also provide new “economic opportunities”. The idea is that if a person has a power source for their daily needs that’s one thing. But what if they had a Suntrunk and a sewing machine?
Other examples are; Lighting a shop at night, cutting wood with an electric saw, grinding wheat into flour or setting up a Web connected computer to offer people a window to the world.
With renewed enthusiasm I set about redesigning the Suntrunk to meet some very important goals.
1. They must be able to produce much more power than the mini chargers. I have now assembled a line of 6 systems that range in power from 10 watts of solar up to 135 watts. The largest unit can provide over 600 Watts of AC power for more than an hour with one day of good solar input. The smaller SR60 unit could run a small sewing machine all day on day’s worth of solar input. People can choose the size needed to fit their specific load requirements.
2. It must be a complete system. All the components needed are in the trunk. There are no additional parts to assemble on site. The Suntrunk contains the solar panels, batteries, inverters and controls for a complete system. The electrical outlets come in three of the most useful voltages. USB plugs for 5 volt power, 12 Vdc outlets for intermediate loads and then 120 volt AC power for all standard AC equipment. The wattage depends on the size of the system chosen.
3. It must be easily transportable. One of the problems with the first unit is that it weighed over 150 pounds. Even though I put wheels on it, it was really too much to move and position. The problem was the lead acid batteries. The units now all have Lithium Iron Phosphate batteries (LiFP). These amazing batteries are the next generation of Lithium batteries. Compared to standard rechargeable Lithium batteries in use today, they are safer and have much less environmental impact. But most important is that they are light weight. For the same capacity of a lead acid battery, a LiFP battery is 1/3 the weight. This makes my new systems much lighter and easier to move, position and ship. The other problem with my first unit was the wooden container that was hard to build and heavy. I now use military transport cases of varying sizes to protect the internal equipment during transport. The larger cases have wheels and handles for easy movement.
4. It must be durable and have a long usable lifetime.Many solar products use the lowest cost components to market at the lowest price. They may last 3 to 4 years before a component fails or the battery pack needs replacement. They sacrifice performance, reliability and lifetime to get the lowest price. To be a useful and valuable energy source a system should perform for 10 to 20 years. My philosophy is to use the very best components. The Suntrunks incorporate the following parts.
Panels: Crystalline panels are proven performers and are produced a reasonable costs.They have tempered glass surfaces that won’t fade and can be cleaned when needed.15 to 20 years of good performance can be expected.
Batteries:LiFP batteries have 3 to 4 times the lifetime of lead acid batteries.Instead of changing batteries every 2 to 4 years, LiFP batteries should give more than 10 to 15 years life.
Solar Charging Controller: By using a Maximum Power Point Tracking (MPPT) charge controllers the solar panels can collect and store about 20% to 30% more power each day. These controllers cost more but will pay off over the long run.
Inverters: Inverters convert the 12 volt battery power to 120 volt AC power. I use only pure sine wave inverters because they will run virtually all AC loads without problems and they are simply built better than the cheaper modified sine wave inverters. This gives you better performance and a longer life for the inverter.
5. Lastly I wanted the systems to be useable by everyone. These systems can be set up in less than 5 minutes. No tools or technical knowledge is needed. Just open the lid, then fold and lock the panels in place. There is no wiring or additional pieces to attach. The system turns on with easy to read switches and has a meter (not blinking lights) to see if the unit is charging or discharging and how much battery power is left. They can be taken down just as quickly and stored in their protective cases.
The Re-Designed Line Up
Over the last year we have built a line of six solar chargers from 10 watts up 135 watts.
All of these units work well however I need to do further testing to verify and improve performance and confirm all features work well even under severe operating conditions. Also, these units were built one by one. I can see many areas where the price can be reduced in the assembly of the second generation units. Also volume purchasing of parts will help me produce the best product for the lowest cost.
So where do I go from here?
I’ve gone through the invention, definition, proof of concept, re-definition, and have built a functioning prototype of each unit. This Kickstarter project is a key part of the Development plan to begin marketing these systems.
I intend to manufacture these units here in Boise once I have proven test results and accurate pricing for parts and assembly. I have formed a small company called “Sunready Power”. Besides myself I have a solar technician and web designer working on this project. However, at this point I have run out of funds.
My Project is:
1. Acquire test and data logging equipment to thoroughly test my prototype units over the next three months. Testing is essential to the success of this endeavor. Needed equipment includes both AC and DC data loggers. An accurate pyranometer for measuring solar input and temperature loggers to examine overheat conditions that may arise. The proper functioning of all the parts working together is off primary importance. Also the safety concerns of fusing, overload protection and overheat protection must be tested. Only by data logging the units operation under real conditions can I be assured that my product is durable, safe and meets its performance goals.
2. Assemble Second Generation units of each of the prototype units. Using what I’ve learned building the first prototypes, these new units will be improved in terms of efficiency, weight and reliability. This activity will also provide feedback on the assembly process and allow for volume purchasing of parts to get a real cost of production.
My financial target is:
$36,900 of which approximately 20% will be spent on testing equipment and activities and 80% will be spent on the production of units and the rewards for backers.
My Project Timeline is:
When funding is secured I will procure test equipment and begin purchasing parts for the assembly of the new units. I estimate that assembly and testing will start within weeks and continue through the end of the project. The production units will be ready for delivery to backers within 3 months or by June, 2013.
Rewards for Backers:
All backers receive my sincere thanks for helping me on this project. I’ll also produce a monthly status report for people to follow my progress. And you’ll receive a full color photograph of the Sunready team with the new Second Generation product line that you helped create.
One of my tasks in life (some people say it’s an obsession) is to increase people’s knowledge and understanding of solar energy and its uses and capabilities. (My other obsession is throw-away batteries. Please recycle your used batteries and try to use rechargeable batteries wherever possible.)
Therefore my rewards for mid level backers are Suntrunk accessories - made up of energy efficient LED study lights, a rechargeable LED table lantern, an easy to use plug in AC wattmeter, and a hand held solar intensity meter. These devices will help you to become more aware of ways to use solar energy efficiently and your solar environment. If you are considering solar in the future, these gadgets will help you plan a system that will better meet your needs.
Larger backers will receive actual working models of various sizes.These second generation units will be of good quality and will have been thoroughly tested. In the future I may contact you for your feedback on the product. If you wish you may continue to help me by offering your opinions and comments on the unit you received.
About Me and Sunready Power
Even though I’m a licensed electrical engineer, I’m also a bit of a hair brained inventor. I do know a little bit about solar energy. I graduated college in 1978 with a Bachelors and Masters degree in Electrical Engineering. My Masters thesis was on a solar photovoltaic power system that tracked the sun and produced electricity and hot water. I built and tested the unit. In those days the best solar cells were only about 8% efficient and cost about $20 a watt. They have come a long ways since then.
After college I went to work for an electric utility here in Idaho in their Energy Management Department and worked on testing new renewable energy systems and conservation programs. After 20 years I left the power company and offered my services on a consulting basis on energy conservation projects, solar PV projects and building custom solar gadgets in my shop. also teach classes on Energy Management and Conservation in buildings and give talks on Energy Sustainability and Carbon Foot Printing.
I’ve built a lot of custom solar systems for various customers. One interesting project was a sleek solar top for several low speed electrical vehicles. These vehicles had 380 watts of solar to boost their range.
However I’m very excited about the line of Suntrunk units I’ve made from 10 watts up 135 watts. I believe these units can be a great benefit to many people for security and safety after a disaster, for improving the standard of living in areas where electricity is not readily available or fuels are expensive and dangerous, and for many recreational uses.
In 2012 I started a company called Sunready Power to develop and market these products when they are ready.
I have a shop and several people ready to build and test the first batch of products.
The overall success of my vision depends on this project. It will provide rigorous testing to prove performance and stepped up production volume to find ways to lower the final price. Over the last two years I have put a lot of time and personal funds to get to this point and look forward to working with the Kickstarter community to take this to the next level. My budget is depleted and without your help it will take years to do the work needed to make these systems available to all who may need them.
So if you believe like I do, that solar can do more things for more people, then help me out with your enthusiasm and financial support. Thank you very much.
Risks and challenges
The biggest risks with offering this kind of product line are; 1. the reliability of the final units and 2. final pricing. First and foremost, the products must perform well to meet performance expectations. Basic testing conducted on the prototype units have lead to many changes and improvements in their performance. I need to do more rigorous testing and therefore need more accurate, and more expensive, test equipment.
Secondly, the viability as a consumer product depends on final pricing. By building multiple units I can take advantage of volume purchasing and streamline the assembly process. It is important that the units retail price be affordable for the buyers. These are the main challenges that this project will address.
I have been designing and testing solar electric systems starting in college and throughout my career. Testing to verify and improve performance is the key to making Suntrunks a viable and useful product for the many applications that they can address.Learn about accountability on Kickstarter
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