I am Bert Green, founder of SolarMill, and I run a commercial woodshop on solar power. Ask Me Anything!
I started SolarMill in 2011 with the idea of using renewable energy to make consumer products. We believe that solar is mature and powerful, and it’s time for others to make the switch. Our mission is to prove that it can work and to set an example for other businesses to follow. Ask me anything!
Hey Reddit, thanks for letting me do an AMA! It was quite eventful. I'll be returning to this post over the next couple of days to check in. In the mean time, feel free to contact us and join us on social media and we will always be happy to tell you more!
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Learn More about us: http://www.solarmill.com/
If you ever want any advice on machining or using solar power, we'll always be here to help.
We use sustainable materials, like FSC Certified Teak and Bamboo. We also use this really cool material called Richlite, made in Washington State, that's made from compressed paper. Our packaging is biodegradable and has seeds in it. You can plant the packaging and it grows into one of 5 diff types of herb or flower gardens. In our day to day operations, I try to minimize the use of solvents and harsh cleaning practices. We throw away very little trash, on average one bag a week. The teak, used in our iPhone cases, comes from managed forests that are replanted (instead of cutting down old growth rain forests).
As someone who works in the lumber industry it's great to hear some discussion about how renewable wood resources are. Thanks.
And thank you for the work you do! Trees are awesome :)
We also have a "deluxe" line of cutting boards that are backed with Portuguese cork. Cork is a wonderful renewable material, they don't have to kill the tree to harvest it, they just strip the bark off and it grows back in a few years.
Do you run power tools at normal 110/220 voltages? Or have you converted all the tools to run at 18 or 24VDC or something like that?
What kind of amp hour storage does it take to keep the shop going?
Both. Typical shop tools (table saw, miter saw, planers) are still using their stock 120v AC motors, so I have to run those through a power inverter. However, I custom built my CNC machine to run off mostly 48v DC. My battery bank is a standard 48v golf cart battery pack, 8x 6v Trojan T-105's. I have been using them for nearly 3 years and they have been fantastic! They store about 10,000 Wh, of which 8,000 Wh is available for use. You never want to discharge lead acid batteries more than 80% (20% SOC). I have a 2,300 watt solar array. On most days I have more power than I can use. Occasionally, (in December) several days of bad weather will bring me to a halt.
This response, in particular this:
Occasionally, (in December) several days of bad weather will bring me to a halt.
Seems contrary to your initial statement:
We believe that solar is mature and powerful, and it’s time for others to make the switch.
In terms of production shops, this doesn't strike me as realistic. As a hobbyist, though, your setup seems like it would cover my needs.
What's your thought on a shop that needs to run 1 or more 220v table saws, bigger tools that take 3ph equipment, and generally have a much bigger power consumption overhead than you do?
Also, the fact we have to occasionally "stop production" is a result of our choice for our production line to be completely "off grid." If you're grid tied, you keep going as usual and make up for it later. Not everyone has to be off grid like us, but even being off-grid the total amount of times we've had to stop is maybe a total of 8 days out of 3 years. That's not bad at all. I've had bigger hangups with broken machinery and not being able to get materials from our supplies than I have with solar.
That's just awesome reliability. O.o
Yes and no. It is true that 8/1095 days isn't that big of a deal, but for a large company it certainly would be as that is almost 2 full reporting weeks where you do no business! Moreover, it is a big deal relative to what solar is competing against given that base load fossil fuels provide power 100% of the time.
Nothing is 100%. We had a hurricane pass through Richmond 2 years ago and knocked out power in my business park for 3 days. I was the only one with power and kept running without any problems. So subtract those 3 days from the 8 total. There's also been a few brownouts, not to mention a few winter blackouts for a couple hours. I kept running through the middle of a brownout because my machinery is totally off grid. Fossil Fuels are not 100% reliable. Truly nothing is. Also keep in mind that when our batteries are empty, we are ALWAYS working on other tasks- cleaning, maintenance, organizing. There's NEVER downtime. It's all a matter of changing behaviors.
He said 8 days out of three years, not one. It's 8/1095, which is a much different figure.
Good catch! Thanks, I have edited it. And as I said, it is a yes/no kind of significance. On an absolute scale we likely won't notice it or care, but relative to peers this type of thing is noticed even if it is silly. OP has been making the argument for solar as a clear switch for businesses, but not having power for something like 5 days can be significant when scales are increased and your competition continues producing. Every business is obviously different, but losing volume can threaten orders and contract fulfillment, not to mention certain machinery and processes take several days to start up once they shut down. So losing power for even a few days can result in added costs and delays beyond just getting power back. I work in finance and when a Company has operations knocked out for a week or so it is in fact noticeable in the numbers and often disclosed in Company filing's as a result. In OPs defense, he has been recommending most pursue an "On Grid + solar" strategy which would help mitigate solar's intermittent nature while also increasing ROI.
Correct, the biggest point that I'm trying to make is that I'm off grid by choice, which might not be a good fit for everyone but something I take a lot of pride in. For most businesses, they can move to grid-tied solar immediately without having to deal with reliability issues. But if you want to be off-grid, if def can be done. I'M DOING IT! Increased reliability is just a matter of more panels, more batteries.
100% of the time? I've been without electricity for a week already this year (we had probably three weeks of no power last year) because the hydro company can't get their shit together. Also had thousands of dollars in damages due to power surges because they half-ass their repairs.
Hydro is usually considered a renewable energy source, not a fossil fuel. But point taken. I am speaking in generalities here, but fossil fuels are basically nature's batteries as they represent dense forms of stored energy over time. A lump of coal will provide the same amount of power when ever, where ever under normal conditions (generally), where as wind and solar are intermittent sources of energy (only when the wind blows only when the sun shines, etc). So basically fossil fuel's real strength is that they will produce energy whenever you want because they are stored forms of energy. The benefits of this are obviously immense, as generators can provide on demand energy in the event the grid has issues even in the event of storms, chaos, and whatever else the world throws at you. The costs are also obvious, such as pollution and noise.
This is all 100% true. It's hard to deny the appeal of fossil fuels. It's cheap, high density energy and available when you need it. The downside is people seem more prone to ignore the negatives, as the costs are distributed, diluted, and hard to quantify directly. Visible upsides to the individual with hidden costs that are shared by all is a recipe for a "moral hazard"
Off grid or grid-tied? If you're grid-tied, you don't have to worry about major start up loads because those surges will be supplied by your utility. If you're off-grid, you're in for a world of fun. :) That's where swapping out motors for DC start to become more feasible, you can run them straight from the battery bank and not have to invest in as massive of a power inverter (and worry about your inverters burning out).
You also lose some power in the conversion from DC to AC, or so I've read. Correct me if I'm wrong.
Correct. Part of our machine design is to avoid those unnecessary conversions.
You lose some power as heat almost regardless of what you're converting to what because of the heat of rectifying thru sizable power diodes and/or switching IGBT's, MOSFETs or other power drivers.
I would think it more efficient to convert DC to AC so long as you can match bus voltage to the drives you're using, though for some 3ph stuff that gets into some pretty high volt ranges (at least, it would take one hell of a battery bank to run the VFD's on my CNC mill, lathe and cold saw that rectify 240VAC 1ph into a DC bus over 300V before changing it back into 3ph 240 again, because my shop doesn't have native 3ph power)
3 phase motors give a nice efficiency boost over regular single or split-phase motors. It's a shame 3phase power is not more accessible. However, you can arrange the Outback Inverters in a 3 Phase configuration, which is just incredible! All you need is 3 of their VFX Inverters. Read their owners manuals to learn more.
ScrewIkea, I don't know if you saw my other post, but you can configure Outback inverters in a 3 phase solution. You just need one for each phase.
I think you pretty much covered my question elsewhere -- I was a lot more curious about overall power consumption. If a shop has 3 phase equipment, their power needs are usually pretty high.
Yeah. When operating on that scale it's crucial to optimize cycle times. You could have a "gentle" strategy that takes light cuts but that's gonna have longer cycle times. I find it interesting that the things that are crucial for a standard machine shop are also the right techniques for a solar powered one. I use a calculator such a GWizard to very accurately optimize my cuts so I have the fastest cycle times possible. I hardly ever break bits anymore. They get dull and then I replace them. I was only breaking bits when I started and that was usually programming errors or crashing into fixtures/clamps. A good Feed/Speed wizard does wonders to push cycle times and increase profitability.
If you're using high quality bits, you might think about getting them sharpened. I don't know what your duty cycle is for any particular bits, but sharpening is usually a lot more cost effective if you're using quality ones.
Most of my end mills are Onsrud single flutes. (which are awesome) I'm saving all the dull unbroken bits and when I have enough of them to do at once I'll send them in for sharpening. But so far, I haven't. I'm interested in how that would affect my offsets. Do you use tool compensation in Mach3 or do you change the effective diameter of the bit in the CAM software?
Occasionally, (in December) several days of bad weather will bring me to a halt
I'm all for saving money, but what kind of shop would accept cloudy weather as a reason work can't be done (Is this a hobby?)?
Used to run a shop. Machines running = profit. Machines need power. We ran off the grid with backup generators. Unless I was trying to stay in poverty, I'd be running off the grid exclusively instead of some hippy bullshit solar power
It was a personal choice to be off grid. I see this as a research company and the mission of this company is to SOLVE the exact problems you are raising. This hasn't been easy. It's not for everyone. I actually recommend being grid-tied to most people so they don't have to deal with most of the issues we deal with. I wouldn't force this on anyone, but it's been such a great experience I wouldn't do it any other way. I grew up in a farming community, so I see this method as being much closer to nature than typical manufacturing.
You sound like a broke queer hippy
/u/Da_Penetrator right now: http://i.imgur.com/1sSvpl3.jpg . HD stands for hard dick.
American Beauty is a great movie
Aside from the CNC, there are several other tools that I think would be IDEAL for DC conversion. Like the dust collector. That thing is an energy hog, and having some speed control to vary the flow would result in massive energy savings. I don't think it would be too hard to switch the standard induction motor mounted to the top of a clearvue cyclone with a golf cart traction motor. This is actually a project that I'm interested in working on, and when finished we'll post the plans in an open source wiki.
Trust Me I'm sure I have a CV in my new home and I'm sure when running the motor uses a ton of energy.
Cyclones are awesome, right now I just have a bag unit and I'm really getting tired of emptying the bag every couple of hours. Keep in touch, I think a 48v DC Dust Collector would be a great solution for anyone interested in off grid woodworking. We'll post plans and part lists when we do the project. It won't be a product for us to sell, just something we'll write an instructable so people can do it themselves.
No No you miss understood me I meant this... Also uses a bag... Only needs changed 2 times a year according to the manual though... http://en.wikipedia.org/wiki/Central_vacuum
Oh, you meant CV for central vacuum, I thought you mean CV for ClearVue cyclone, which is a popular brand for wood workers. But yes, vacuuming in general uses lots of energy.
Your drone video is seamless(seemingly), was it all a long take?
Yeah, it's uncut. One of several takes before we got it right. A local VCU student built the entire drone himself from scratch and was nice enough to bring it by the shop on Wednesday. That thing is powerful! It jumps off the ground with a twitch of the stick. It took two people to fly it, one to the control the flight and another to aim/pan the camera.
I love the appeal of sustainability but financials play a huge role as well. How long did, or will it take for your energy savings to give you a full ROI on your setup costs?
There's two major ways solar can be implemented: grid-tied and off grid. Grid tied is always a "blend" of grid and solar, and depends on the time of day producing. Since I wanted to be able to honestly claim my product was "made with solar" I decided to go off grid. However, grid-tied will usually result in a faster ROI since all the power produced is sold and the total equipment invested is cheaper. I recommend grid-tied for most people getting started, you can always upgrade to off grid or hybrid solutions later. Since I'm off-grid, the payoff will take a little longer but I should break even in about another year or two. After that, I'll completely own my power generation and have "free electricity" for 20 years.
I'm intrigued. It seems the marketing gimmick of being able to say "made with solar power" has actually pushed your ROI further away. You advise others to start on grid first and transition over.
I think you're confusing marketing gimmick with honesty. A "gimmick" would be to buy REC's and then claim the product was made with wind or solar energy when the actual energy that went into that specific product was fossil fuels. We actually generate our own power. If it was a marketing gimmick, I'd prefer to be only one doing it and keep the details to myself. Instead, I'm doing everything I can to encourage others and help them make the switch.
What first got you interested in solar power? How old were you?
11 years old. I got an electronics learning kit from the Science Museum when I was in 6th grade, and it included a tiny little solar cell and a 3v motor. I remember thinking at the time how cool it was to run a motor on sunlight. I had it sitting in my bedroom window for months and every afternoon at about the same time the motor would start to run on its own. I think that stuck with me. 20 years later, I'm running commercial machinery on solar power. And they STILL make those solar learning kits: http://www.houseofrave.com/media/science/solar-energy-kit-big2.jpg
They make all kinds too, I have one that lets you build a solar powered walking robot.
My main piece of machinery is essentially a solar powered robot. Unfortunately, it does not walk.
What is your company's biggest contribution to save energy?
Research. I've come to some interesting conclusions based off first hand observations that I would never have anticipated. Dust collection is a huge area of energy usage in wood products manufacturing, so we're working on some open source controls that can yield significant savings there.
Also, behavior. One of the negative commenters above said it was unreasonable for a commercial business to stop production due to weather. The only thing that slows down due to weather is our production line machinery, and that's been for a total of 8 days over 2.5years. However, there's so much other work that a business needs to do: packaging, web design, cleaning, machine maintenance- that we're ALWAYS busy and working. It's all a matter of changing our behaviors to work with nature instead of working against it. In the grand scheme of things, long term sustainability is more important than short term profits.
- What other products do you foresee producing in the future?
- What has been the hardest part about going the renewable energy route?
- What materials, in your opinion, should consumers be avoiding the most and what renewable materials are you most excited about using more of?
1) Always a tricky question to answer what's next, I like to keep things close to the chest until we actually have a product ready to ship. That's just good business practices. But, in the near future, I'd like to "scale up" production of our iPhone cases and start promoting them more. We've made around a hundred and sold most of them, but then the Z-Axis on my CNC started getting loose and isn't holding the tolerances that I expect. I'm thinking about doing a kickstarter to fund a separate benchtop CNC that can hold the level of precision I demand so we can really launch that product to the larger market. I'm torn between moving the company either more towards furniture and home decor or whether we should move more towards fashion and personal accessories. We might do a little of both.
2) If you're grid tied there is no hard part, other than having the money to finance the installation. If you're off-grid, then you need to schedule your production, watch the weather, and keep an eye of your power meters. You also have to have a quality, commercial grade power inverter than can handle the brutal startup loads of woodshop machinery. After 2 years of struggling with cheap Chinese imported inverters, we finally bought a quality Outback VFX 3600. That thing has been amazing.
3a) Meat. I hate to say this, because I love a good burger and a good steak. I'm not a vegetarian, but I have so many friends that are vegetarian that I've learned you can have a great meal that tastes awesome without it having to be 1/2 animal (shoutout to BenCpz for educating me!!!). If you really look at the energy required, the foods we eat may be having a bigger impact on our environment than the products we purchase. Eat meat in moderation, it's extremely land and resource intensive. Palm oil is also really bad in that so much of it is coming from rainforest clearcutting for palm plantation. Every bite you take changes the landscape
3b) Molded paper fiber products are interesting to me. Wood (when properly managed) is a wonderful renewable resource. We can always grow more of it.
Awesome reply. Thanks a bunch for doing this. I totally agree with you on the issue of meat and palm oil. Meat is always a tough one to give up completely, but cutting your intake isn't too hard.
I would love to learn more about molded paper fiber products; they might be able to replace styrofoam for protective packaging, which would be huge since styrofoam is horrible to try to dispose of.
Thanks again for the AMA. Best of luck to your business.
I'm thinking about going beyond replacing styrofoam packaging and how molded paper can be used for the actual products themselves.
Yes! Definitely. I can't wait to see some more of this. Do you know of any companies that are working on using this material in new, innovative ways?
There's some interesting work being done with growing fungi in molded containers. I wonder if that could be used for the core shapes of furniture (under the upholstery).
Any chance you could send me a 550 x 90 x 10mm piece of richlite to new Zealand?
I build guitars and I'm trying to source more eco-friendly alternatives to the mainstream materials which are pretty much tropical/rainforest timbers like mahogany, rosewood, ebony, etc. They're are plenty of products which exist, or are being created, which would do just as good a job as these exotic timbers but without the ecological ramifications which are rarely positive.
I've built guitars from reclaimed offcuts (http://i.imgur.com/RfLyL2O.jpg), salvaged native timber from dilapidated furniture (http://i.imgur.com/z9kfQvv.jpg), wood salvaged from old battleships (http://i.imgur.com/mAJlAlC.jpg), and generally try and be as responsible as I can be with regards to the sustainability and origins of the materials used.
I've heard of Richlite and have seen it used in guitars previously (Martin acoustics use it), and from what I've heard it's a straight swap for timber but without any of the ethical concerns. I'd like to try it for myself and see how it holds up with regards to fretting, inlaying, and as a playing surface. But in NZ it's difficult to obtain since I don't think a dealer exists.
I'll see what I can do. send me an email and I'll get a material price and shipping quote to you. [email protected]
How possible is it for a homeowner in Ohio?
If the town of Burlington, Vermont can do it, you can do it.
This is great. Where can I find these cutting boards?
We're on Amazon! They've been great to work with and it makes our product available to a large market nationwide and fast free shipping with most orders (esp if you have Prime).
Is your use of solar power limited to your business or do you incorporate solar into your home as well?
I rent an apartment and don't have solar panels there, so for now it's limited to the business. I also drive a car and eat hamburgers. I'm far from perfect. But one of my favorite quotes is: http://en.wikipedia.org/wiki/Perfect_is_the_enemy_of_good
I'm learning to eat less meat, drive more efficiently, bike when possible, and always work towards being better.
Question for you. I am debating about installing in ceiling LED lights in my house and running them from a couple of deep cycle batteries, charged via a solar panel. I live in Florida so there is no end to the sun down here. I have 2 questions for you.
Would it be best to use 12VDC LED lights. I know voltage drop would always be a consideration and I have to calculate my wiring accordingly. But sticking wit 12V would make for a simpler system.
Or should I get an inverter, and run 120VAC led lights?
Either installation would be completely separate from the houses existing electrical system. I know I can't get off the grid, but if I could light up my house like a Christmas tree at night using LED's on battery power alone, I would love it. I've been farting around doing build schematics trying to come up with costs with both systems. Do you have a preference?
Solar Panels > Batteries > LED Driver > 12v Lights. You might need multiple drivers (kinda like a power supply) to optimize the system. That should work great, but you should consider a low battery cut off so you don't drain the battery too low by accident. Add up the total amount of lights you want to run (by watt) and then divide those watts into your battery banks capacity to make sure you have enough run time for the night. I would advise not going below 50% SOC in this application.
Hi Mr. Green! Thank you for doing this AMA. What did you do before beginning this business in 2011? What was your experience with power-related industry beforehand? What is the number one piece of advice you would give to a person who wanted to start their own business in this or a similar field?
I was doing "Design/Build" for Richmond restaurants and bars. Which is like being both a designer and a contractor. I would do 3D models of interior layouts, help with space planning, and build everything from signage and reception desks to lighting and bar displays. It was fun, but if you don't bid right you lose your shirt and don't make any money. My heart has aways been in product design and mass production, so being able to run this company is a dream come true.
My number one piece of advice: work for another company that does something similar and learn EVERYTHING you can about how they market, how they operate, and especially- how they estimate their costs and bill their clients. The more you can learn about how other people do it successfully, the better off you'll be not having to figure it out "the hard way." This is why internships are crucial, but sometimes a 3 month internship is not enough. Get out there and work for people that do it.
With making the move to Solar energy, have you seen an influx in orders?
I started the business with solar in mind from the beginning. It took me about 16 months to build the machinery and setting up the production line took almost another year. We've seen a nice steady flow of orders, but we're still very small and could always use more supporters/advocates.
Do you heat/cool your shop with the solar as well? If so, what is included in your setup?
Very little. Since you're asking this question, you prob already know that heating and cooling are very energy intensive. I don't use AC much in the summer, but when I do it's only in the office and when I have surplus power available. I just run an extension cord into the office from my inverter. For the most part, I just sweat it out. I see AC as a luxury and heat as a necessity. In the winter i mostly use a kerosene heater (believe me, I hate doing this) for the shop space and a little bit of grid-electric baseboard heat for the office. I can't work in a 30deg space, and there's not enough solar to heat my poorly insulted 2000 sq/ft workshop. I rent my workshop, so there's a limit to how much I can do to make it perfect for heating an cooling. One day I hope to own a purpose built space designed to take advantage of natural cooling and in-floor solar thermal water heating with top of the line insulation. This entire topic points the the important role ARCHITECTURE plays in energy savings. I cannot overstate how important good building design is. Great question!
Are you responding to these question from a solar powered device?
Yes, I charge my laptop from my Outback VFX 3600 AC inverter. :)
I'm actually at some point going to try hooking a small mill up to solar power. We have to get the mill and the solar first... do you have any advice?
We were thinking a small one just so we could process and use what we cut. Can you think of any major problems to warn me about? W3 really still are on step one.
I recommend golf cart batteries and golf cart motors. You can even use the ESC (electronic speed control) so you can get the perfect chipload and feedrate without burning up your blades. Lots of torque, and off the shelf parts. Solar Panels charging a golf cart battery bank and running a golf cart motor is a great solution for many off grid motor driven machines. Just please don't call it a SolarMill, that's us. :)
Mention of ESCs and motors makes me want to make an 'adult size' quadcopter! Strap that puppy on and ZOOOOOOM!
I want to see you do this and post a video of it to YouTube asap.
I worked for a company called Hemlock Semi-conductor. We were building a polysilicon plant in Clarksville, TN. Unfortunately, due to tariffs from China, we had to scrap a 2 billion dollar plant before we even made a product. I believe this was a direct result of tariffs placed by the United States government on imported chinese solar panels. Are you familiar with this?
Not really, since i built my system myself I'm not eligible for tax breaks and I have not applied for or received any State or Federal Grants, so I'm not familiar with those type of funding issues or tariffs. Best of luck! I hope you guys find a work around.
On what scale does your company run? I know it takes a lot of power to run a machine shop. How well do the solar panels power your machines?
We've shipped cutting boards to 49 states, the Virgin Islands, and Australia. We have 2,300 Watts of solar panels and a 10,000 Wh battery bank. Our Outback AC Inverter is able to run 3,600 Watts of machinery. It can handle the startup surge of my tables+shop vac and run other smaller piece of equipment, such as a router table, all at the same time. I can run my CNC machine for nearly 8hrs continuously from a single days charge, depending on the Spindle RPM. Paradoxically, light engraving cuts take more power than roughing/hogging operations because of the higher RPMs. (higher RPM engraving cuts like 28,000 spend more power driving the fan attached to the motor than actually required by the bit engaged with the material). Using a 1/4" endmill at 18,300 RPM, my entire machine, including dust collector, draws right around 1,000 watts. At 28,000 RPM, it takes an additional 250 Watts, and that's all being wasted by the fan on the universal motor, not the bit. Weird, but true.
Oh wow that's very interesting. Have you looked into other forms of alternative energy? Solar is probably the easiest accessible form but just asking. Also where are you located? And I love your philosophy! That's how all companies should be
We are in Richmond, VA!! And by we I mean me, my Parents, my dog, and a few friends that help me out on occasion. I like all forms of renewable energy, but solar is by far the most accessible. Wind needs to be about 100M off the ground to have the right energy density and laminar flow. Anything that claims to make rooftop wind energy I would be highly skeptical of their claims. Hydro is great, but its' hard to avoid the environmental damage to rivers and streams. I like tidal, but I live a hundred miles from the ocean. This is why I think solar is the best choice for most people.
At 28,000 RPM, it takes an additional 250 Watts
Have you measured the motor temperature, and experimented with partially blocking the air intake to that fan, to decrease the fan-power a bit?
I've experimented a little with blocking the air flow, but your suggestion makes me want to revisit it. The problem is being able to unblock it at the lower speeds. I think a water cooled, VFD powered spindle would ultimately be the best solution.
Have you heard about the solar roadways that have been discussed recently?
What do you think about them? Do you think this is something that is actually possible? Do you think it's something we should strive for or is it a lost cause?
I think it's a bit silly. There's so much "low hanging fruit" out there, (like hundreds of acres of flat commercial rooftops across the US), that I think squeezing a complicated system into a road surface that gets abused with traffic seems like a waste of money. It's a cool idea and very nicely rendered, but not where we should be focusing our efforts right now. However, I do applaud their ability to get people excited about solar. That's always good.
Solar roads are a scam. They could be used for small architectural plazas or possibly parking lots, but they will never be approved for public roads for a variety of safety reasons. They'll also be FAR more expensive than traditional arrays, while producing far less electricity.
Precisely. I like your plaza idea, though. Hadn't thought of that. It would be a great way to engage the public without the technical problems of heavy loads.
Whither goest thou, America?
Towards the sun, where light breathes life to curious machinations.
Have you ever thought about doing anything with 3d printing?
We've already started! We collaborated on a short project with Andrew Sink, an local expert on 3D printing. He brought on of his portable machines to my workshop and we spent an afternoon printing refrigerator magnets and recording power measurements. We estimated that it takes 15 Wh of energy (or 54,000 joules) to print each magnet. Which means that from our 8kWh battery bank, we could print 533 magnets from a single day's charge. Recording power and energy is one of the core research methods that we are using at SolarMill. It allows you to optimize production.
Through reading these, I'm wondering why you're talking in terms of the batteries, as I understand there's a loss in efficiency when going to the battery. I read below you have 8000Wh usable battery storage, and the solar array gives 2300W at peak. If I assume it remains at peak for a good amount of time, it would only take 3.5 hours to fully charge the batteries. Do you use the additional sunlight to power anything directly during the day? Unless I'm missing something, it looks like you could print closer to 1000 magnets in a single day if skipping the batteries.
You just hit on the magical sweet spot I like to call streaming or "direct balance." (Direct balance because it's directly from the sun and balanced for the load). If you have your batteries already charged and match your loads to the amount your using, you actually bypass the batteries entirely for several hours and get a 15% efficiency boost by avoided the electrochemical conversion process. I try to do this as often as possible. It leaves power in the batteries for when I really need it and increases their longevity. Sounds like you have the perfect mindset to get involved in this type of work! What do you do??
Thanks for the reply, and it's great to hear that energy is put to good use. As a bit of a follow up, say the batteries need recharging in the morning. To minimize battery usage during the day, have you ever tried to use only say half the array to charge the batteries while using the other half directly? (I hope this doesn't come off as condescending, it sounds like you certainly know what you're doing).
As for me, I'm a student currently, studying chemistry with an interest in photovoltaics. I'm currently in a lab researching quantum dots which could eventually be important in increasing efficiency and decreasing the price of solar cells (along with a number of other applications).
For the best battery life, you actually want to charge the batteries back up as quickly as possible. The longer they stay at a reduced SOC they more they degrade due to sulfurization. And since I can take power from the system WHILE charging, splitting the array would do very little to help me other than further complicated the system design.
Oh yeah, this was a ton of fun! Thanks for sharing your space, Bert! Always cool to do research and collaborate with local makers!
Absolutely! It was a fun day. I'm excited about doing more with 3D printing.
If you could go back two years in time, would you do anything different?
If I could go back 3 years, I would have considering buying an existing CNC machine and retrofitting it instead of building my own pretty much from scratch. I spent months on the frame alone. I learned a lot from it, but I could have gotten things up and running faster by focusing on modifying an existing platform instead of re-inventing the wheel.
With areas like Alaska, where during the winter we only see the tip of the sun for about an hour (lazy ass sun); how would this be useful to us?
No during the summer, the sun never wants to set and there might be solar murder. :P
You're obviously picking a situation that would be cramming a square peg into a round hole. That's about as useful as asking how practical is wind energy in outer space or how good is tidal energy in Nebraska. Solar works great for me in Virginia, as it does in most states.
Not really. There is this big push to go clean energy, but you have areas like Alaska where that is not as feasible as it sounds. The central part of Alaska does not have that much wind; the solar is only good during the short summer we have, geo-thermal might be possible in some areas, etc. So once again; how will solar energy help me in Alaska.
You're answering your own question. Solar does not sound like good fit for your situation. You should consider a bio-diesel generator for electricity and wood/biomass for heat. Either way you're going to have to bring energy to you. Alaska is a special case scenario. I hear it's beautiful, though, and would love to visit one day!!! My only hope is that what I'm doing here in Richmond can help preserve the area where you live by reducing the effects of climate change.
Winter - Beautiful from the indoors. -40 is hell for a Texas boy like me
Summer - Great, minus the b52 sized mosquitoes.
It's kinda like a frozen Australia. Everything wants to you dead, just it does not use poison, venom, or some weird toxin to do it.
How long have you lived there?
You'll have to look at the price you currently pay for electricity in your cabin/community, use http://pvwatts.nrel.gov/ to get a feel for the solar possibilities, and compare the prices.
It seems everything is expensive there, if you pay a fuel price of $25/gallon for your diesel generator, every gallon saved when using PV helps.
All hail the wood burning stove.
Properly managed wood forests are a great source of winter heat, and are carbon neutral. I wish I could put a stove in my shop. When I get to the point that I can build out a space suited for my business it'll def include a wood stove, so I can take advantage of burning my offcuts.
So how much did all this cost? This would be awesome for my shop.
I have 9 panels and they produce a total of 2,300 watts. They cost me about $2,500, but then you have to also add in the cost of the charge controller $800, the batteries $900, the AC inverter $1900, and all the wiring, setup and installation. All told, my system is about $5k, which comes to about $2/watt installed. A lot cheaper than the average $4/watt installed because I did it all myself. I have plans for a simple ballasted solar mount that I'm going to release as open source for anyone that wants to mount panels on a flat roof without drilling through the membrane.
Very cool. I'll have to look into it. I'd like to see everything converted over to solar (and possibly wind, someone left an old wind generator on top of my shop but it's been disconnected for years), house and shop, but the shop is definitely the place to start, I'd say.
As you may have seen in my other posts, I recommend grid tie for most people. It's cheaper, with a faster ROI, and you don't have to worry about start up surges burning out your inverters.
Hi, my name is also Bert. What do you think of the prospects of solar energy in equatorial countries where there is generally lots of sunlight and lack of available investment?
Always nice to meet another Bert! I've only met 3 others in my lifetime. I think your possibilities are even better than mine, but financing is def key. Look for an area with limited or unreliable infrastructure but steady growth. I think that'd be a good place to start.
My cousin is also a Bert. Other than him I have not met a single one yet. I work in the borehole/water well industry and it seems like solar is really taking off here (Kenya) in that particular use - pumping water out of the ground. But there is very little interest in general purpose/power grid level solar. Our company/community pays 25 us cents per kilowatt from the grid, averaging about $1000 a month. Is it cost effective for us to switch?
instead of "switching" it sounds like you should get involved with your local company and encourage them to start investing in solar. It sounds like this is a co-op scenario. They could immediately start adding solar to their mix.
Nope getting the power company to switch wouldnt work. The 'local company' is Kenya Power & Lighting, the national grid. They dont really take suggestions from lowly customers like us. Though I must say in the last couple years they have been investing a lot into geothermal, Kenya being one of the few places in the world able to use geothermal on a large scale.
Fascinating. I have no idea what the import costs are there, but here it's about $1/watt and you can see a return in 5-7 years. Good luck out there!
Hey man, thanks for doin this. I actually have noticed that where i live there are hardly any solar panels on houses or businesses. Ive always been interested in starting a business to install these. How would i go about that and could you possibly tell me what profit margins are like?
I am not a solar panel installer and do not make any money from the sale or installation of solar panels. I strongly believe it's a great solution, and have built my business around using solar, not selling solar. I would recommend getting certified and looking for work under an existing installer to learn from them before going out and starting your own business doing it. Good luck! We need more installers. Solar is one of the fastest growing industries.
Oh ok. I guess i just read it wrong. My apologies. So what have you saved by switching to solar? I agree. I think it should have been alot more universal by now.
I've reduced my carbon footprint and educated thousands of people on the benefits of solar. I consider that achievement to be invaluable. Monetarily, my system has mostly paid for itself, about another year to go and I'll essentially have free electricity for the next 20 years.
What's the hardest type of machinery to run on solar?
If I had to guess before I started this project, I would have thought it'd be my tablesaw. But, surprisingly, my miter saw and my "oscillating edge belt sander" caused more problems than anything else! I've noticed they both have gearbox drives, and gearbox's have large starting inertias. Before I upgraded to a quality inverter, the belt sander killed 3 chinese inverters (from eBay) and the miter saw would trip my eaton power ware inverter nearly every time. I have meters on everything now, so I can see that when I turn on the miter saw it surges at nearly 110amps!!!! But it's run power (once spinning) is only 2/3's that of the table saw. The belt sand is even crazier, that only takes 200watts when running, which is nothing, but it's startup is over 80amps. Start up surges require commercial grade hardware and are prob one of the biggest reasons why cheap inverters don't cut it for woodworking but are just fine for electronics/computers. Also, modified square wave inverters (like the eBay chinese) cause nasty eddy currents in the running motors. I could hear them hum when running. Quality hardware with true sine-wave output has fixed all those problems, though! I have an Outback VFX 3600 Inverter and an Outback Charge Controller and I highly recommend them. Practically bulletproof hardware.
Any details on your CNC machine you could share?
Yeah, I've learned that dust collection can be a bigger load than the cutting head. Vacuum clamping is very energy intensive, so i use mechanical clamps (t-tracks) and screws whenever possible. I used one or two size larger pure copper wires for most of my interconnects to save on voltage drops. Never guess for speeds and feeds. I use GWizard calculator to optimize all my cuts for the fastest possible cycles times. Higher surface finish and low feed rates require much more energy because all the other subsystems are running and sucking power during that time. But the biggest thing is this: if you are you are using a CNC to make consumer products, it does it the SAME EXACT WAY EVERY TIME. Which means you can measure the power it takes, and use that to schedule your production. My coasters require 90 Wh each. If my battery bank is only 40% full and I want to take it down to 20% on the next run, I have 2,000 Wh available, which means I can make exactly 22 coasters and hit my mark EVERY TIME. This way I don't have to worry about running out of power and having a machine crash in the middle of a run. 15% of my machine efficiency is special controls and wiring, but the vast majority of savings is best practices and knowledge. Send me questions [email protected] any time, I'll always be glad to help a fellow machinist.
Cool. That's extremely precise. What about mechanical design of the machine? Did you base it on an existing machine?
Not a machinist yet, but I've been following some CNC threads, sites and subreddits for a while trying to decide what machine to build and whether it's a crazy idea.
I used 8020 Router parts for my linear guides. Rack and pinion drives are pretty efficient. I designed and built my own frame, spindle mount, deck, and Y carriage plates. Be careful not to go overboard with your stepper motors. Because of how they are driven, they use pretty much the same amount of power regardless of the actual load on them, so oversizing them means wasting power that's not needed We're running 380 oz/in motors on all three axis, (dual on the gantry X axis). They take around 250-300 watts total depending on how many axis are moving at once and what feedrate. Actual load from the cutting doesn't make a big difference. Servos may be even more efficient, since they only use power to correct position based on the encoder. This is an area I'm interested in researching more.
Power use by the stepper motors:
Maybe you already use a system like this example, where 15V is used for the (high) power needed to accelerate/decelerate the moving mass, and once in place the voltage(and thus current) drops to 3.3V for positioning only.
I don't have that level of control. I'm using a pretty standard stepper driver, which is a current chopper style. 3.5amps per motor. I think servo's may be more power saving since they only use power to correct position. This is an area I really want to do more research on. I sell my consumer products to fund my research addiction.
How many square feet of panel to get a kw these days? If I recall correctly 9 square feet is what it would take if 100% efficient.
I don't really think about it in terms of square foot. I have plenty of space on my roof for the panels. When I first started, I had 4 panels mounted on a movable cart that I rolled in and out of my garage door everyday and they made about 1,000 watts. It was about 9ft square, so 81 sq/ft for a kilowatt. I'm not sure how that really helps. The efficiency number people quote for solar is a bit of a lark. That's efficiency based on converting 1sq/meter of sunlight to electricity. It's useful for comparing one solar panel to another, but completely irrelevant for company solar to other sources of energy. After all, coal has one of the highest energy densities around, but it's essentially compressed pant matter, which was made with solar power, millions of years ago. That means it's hundreds of square meters of sunlight over millennia.
Someone needs to genetically engineer a plant that collects lots of sunlight and has an outlet at the base of it stem.
That sounds absurd. Until you really think about it. This could actually be doable. I think bioengineering is the future. Lots of cool things going on right now, such as algae being used to create bio-diesel.
How much did it cost (out of pocket) to get your shop setup to run off the grid?
I've been collecting tools and resources for over 15 years. I'd say all hand tools, sockets, welding stuff, power tools, etc run into the tens of thousands. The solar stuff is prob around $5k, but you'd either need to know how to install it yourself or pay an additional 50% of the cost to have it properly (and safely) installed. A general rule of thumb is $4/watt installed. Which makes sense. My 2kW setup is prob about $8k installed.
thanks, I was talking about the solar stuff. I see more and more people doing this on residential houses, and was contemplating doing it myself. $5k-10k is reasonable, and I know here, there are some government rebates for doing it.
Go for it. I hear it adds nice resale value to the house. There's so much information online, I was able to teach myself.
Keep in mind though, you can't get ANY rebates if you do the work yourself. Practically all rebates and tax incentives require the work be done by a certified installer. This is to prevent fraud and to insure the work was done properly. The amount of money you save by doing it yourself it almost exactly what you'd save from the rebate, but you can't have both. They end up averaging out to about the same. Unless a person is particularly competent with this kind of work, (and I'm sure you are) I'd recommend having a professional do it. Solar involves dangerously high DC voltages and requires good grounding for safety. Batteries release explosive gases and require proper venting. Racked must be securely installed or risk being torn off in a storm. If you burn your house down or someone gets shocked from work you did, your insurance may not cover it. CYA.
What do you do when it is cloudy?
Depends on how cloudy. It also depends on how much energy we have left over from the day before, and what the forecast says the weather is going to be tomorrow. If I have 8 kWh available in my battery bank and I know it's going to be sunny tmrw, I might choose to use 5 kWh of that today knowing that it's going to recharge fairly quickly tmrw. However, if it's been cloudy for 2 or 3 days and I know it's going to be cloudy for at least another day, I might choose to keep that energy in my batteries and focus on low energy tasks like printing and folding labels, hand sanding cutting boards, or updating my website. There's so much to do when running a business that even when we don't have "production" power available there's still a lot of other things that need to get done.
what do you see the future of solar power being?
Actually using it on a large scale. I'd like to see panels on almost every roof. We'll still need other sources of power for inclement weather (like gas peaker plants) and better ways to store for overnight usage, but a smarter grid could allow sunny parts of the country to provide energy to parts of the country under cloud cover.
Beyond your solar powered nature, what other environmentally friendly practices does your business use? For example, do you use truly sustainable lumber? Do you directly participate in replacing the timber harvested for your lumber?
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