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Energy / Re: Is Solar Right For You??
« on: September 03, 2018, 09:39:32 AM »I've been living off grid for several years now, in various conditions with various access to power, but always solar power.
I've worked as an Appropriate Technology specialist on an off-grid project in Spain, maintaining all vital technical systems.
I have experienced varied forms of living without AC, washing machine, vacuum cleaner, dish washer, fridge, or even a decent stereo. I have also learned a gazillion different combinations of solutions that people living off grid uses, and which can be recommended in what situation, what to prioritize when working from scratch etc, so feel free to ask me stuff.
I'll give my two cents here, with my most notable experiences when it comes to solar and energy use>
Firstly you need to make a realistic estimation of your energy use and solar potential. If you'd build a system according to the consumption of a normal home you'd probably end up broke. Realize that you need to switch light to LED. All of them. You might have to take a hard look on what you really need, and how much more infrastructure costs goes up to meet the demands of some behaviors and comforts. You need to assess the local weather conditions particularly number of sun hour on average per week or month, not only per year. Your batteries charge won't last a season, so adapt everything for the worst conditions expected. Here is where a petrol generator can be an acceptable compromise and redundancy, to off-load peaks in lack off sunlight in order to save greatly on the overall infrastructure cost in some cases. In places with more overcast weather it can be a good idea to look at mono-crystalline thin-film solar panels, rather than traditional poly=crystalline solar panels, as the former is completely insensitive to partial shading, and performs much better under lower light conditions. This at a loss of some over all performance and top performance, making them slightly bigger per rated Watt, but much, much lighter.
If air conditioning is needed, this is typically the largest drain on any system, they should be avoided if possible, and relatively cheap and energy-efficient thermal mass based options can be made if you own the land. Next is electric water heaters, and after that refrigerators, which can be replaced with ones that run on propane or butane. Washing machines that needs to heat water takes lots of power, and one option is to get (or build, it's easy) a solar water heater, since electric water heaters typically is out of the question in a solar powered setup anyway, and gas heaters are expensive to keep with gas. Then feed hot water to the washing machine, and make sure you have a washing machine that has a program with no water heating, so the machine does not heat the water itself. Even with temperature control on, you can feed hot water from a solar heater to save on electricity. One approach I see sometimes is having a smaller solar system, with gas fridge, and use a small petrol generator when using the washing machine. After these big drains, water pumps may use lots of power or almost non at all there is often great efficiency to be found in designing your off-grid water system correctly. Self-siphoning solar water heaters for example, does not need a circulation pump. A pressure controlled expansion tank a and a back-up IBC gravity tank for your water pump helps keeping the pump at optimum performance, and gives a good margin of water during any power failure. You WILL run into them. If you intend to get fresh water from a pressurized reverse-osmosis filter, note that those needs a good bit of power too!
I can HIGHLY recommend investing in a portable petrol (or gas converted) generator when building any energy system, BEFORE buying anything else. It will get you out of situations you didn't know you could end up in. It's the best off-grid life-saver ever. Period. I'm serious. And make sure that you have a way to use it to charge your solar battery array (and you car battery!). Even if you don't run out of power, you often find yourself needing to float charge lead-acid batteries during overcast periods, to keep up the lifespan of the batteries. Keeping them from being fully charged over a longer period builds up sulfates and reduces the lifespan of lead-acid. You might need to get a freestanding AC charger for your batteries unless your equipment already has such input options, but I always prefer and recommend to have functions in separated units, it tend to make it more flexible, easier to diagnose and better adapted to the individual use-case.
I have found that I actually can live without most stuff, since I mostly travel. I prioritize a decent stereo, but instead of investing in a bigger system, and since I move around a lot, I bought Minirig brand portable speakers and sub-woofers, generally considered to be "the Rolls Royce of portable speakers", a superb durable option built in UK, that technically works as a self-powered line-arrays, as they can be chained in series ad infinitum. They are good for about 30-40 hours of serious use, and I keep mine on for days in a row playing audio for my laptop or phone. They charge via a sturdy barrel jack to USB, 5V 800/900mAh and I tend to plug in and charge one or two every other day when the sun is up. They can also connect audio via Bluetooth, and pair up for true Stereo. They are powerful enough to make windows rattle, and two speakers and two woofers fits in a decent shoe box. This does wonders for taking load of my energy needs. See
As I find computers hardest to live without, and a constant drain on off-grid systems in general, I'll touch upon that a bit.
For a laptop I have chosen a custom built ThinkPad, which are great durable machines with a never ending supply of parts, upgrades, OEM and after market options and accessories, and many many options for docking station, batteries, screen resolution and screen brightness, power adapters, keyboard layouts in any language, etc. which is really great as you can configure and adapt them according to your needs and situations. I got mine with an extra big battery, plus an additional slide battery that uses the docking port, and still have the stock 6-cell battery as backup, for a total of 24 cells(18650 lithium), and I have a genuine dual power supply that connects to either 120/230VAC or 12VDC. I chose a modern i7 processor due to it's finer, more energy efficient chip architecture, which still uses lots of power stock, on factory clock-frequency for best performance, but can be down-clocked (restricted) for slightly less top-performance, to run cooler and much more energy efficiently. Otherwise screens, no matter what device, is what takes power, the bigger, brighter, higher resolution, the more power.
Other popular and common professional work laptops that you prefer can be good options, but there is really no substitute for ThinkPad's when it comes to price vs options, reliability, durability, upgrades, accessories, global and universal availability of parts both new and second hand, and people who knows how to repair them, etc. It is also easier to find drivers, and if you run Linux, you will basically never have any issues with drivers on a ThinkPad. This is something I value highly when it comes to sovereignty. If your computer needs are limited, Arm-based devices such as tablets and smart phones are more energy efficient and can charge directly from USB, putting much less strain on the system. You can always get a Bluetooth wireless keyboard and mouse for a tablet.
I can cover all my personal power needs with just my 300W portable roll-up solar panels and affiliated electronics, that all fits with the other gear in my hiking backpack, charging the batteries of my devices that runs autonomously during the night. I can hook it up to any 12V lead-acid battery when I want. This will eventually be installed in my planned cycle-touring rig, an ultra-light camper trailer, with solar on top. I want to have electric assist, which means higher voltage DC motors and battery packs, which is why I opted for high-voltage thin film panels, to avoid stepping up the voltage to charge them.
Personally I've had it with lead acid batteries, and plan to build my own packs using 18650 lithium cells, using the brilliant DIY battery-pack building-kit with stacking modules from Vruzend. See
Many times cheap small portable pocket lithium battery banks with built in solar chargers can be a great addition to a smaller system to off-load all those things that you power or charge with USB. I have a neighbor that uses them stationary in her windows, with USB LED strips connected, as her main light source.
Finally don't forget cables. Especially DC cables could end up being a significant cost and power loss, and source of failure and catastrophe. Don't fall for any temptations to place components any further apart than absolutely necessary, and never use thinner cables then recommended when calculated properly. Also never forget to install a correctly sized FUSE between critical components. It WILL save you from expensive lessons. Do note that you can NOT use AC type automatic fuses in DC systems, this is a VERY common cause of unintended consequences among DIY solar system builders.
Happy Basking!