Off grid Solar Integration and how it can fit into your community
It might not seem like it, but a community of like-minded people will often times work on project together. A bar or hangout, meat processing house, or even powering your mesh network to ensure uninterrupted internet are all potential reasons to have solar integration in mind during development. As we seek different ways to opt-out or Swarm-Out of the system, we look for different ways to do that. Mesh networking is one way some small communities are getting out of the high cost involved with internet. When everyone is chipping in to pay for it, you want to reduce costs as much as possible, that includes electric for a relatively high powered mesh router.
It’s definitely a good idea to start small with your first solar integration project. Some good starting ideas might be a small shed, office, or barn. This lets you generate your own power and to start building a permanent home, or simply avoid digging a ditch and running a couple hundred feet of conduit. I want to be clear up front, I don’t get too detailed and don’t recommend solar integration if you plan to stay on grid. It just doesn’t make enough sense starting out. Solar integration really shines (pun intended) when you’re in a more remote or otherwise inaccessible area.
If you’re looking for a light in your workshop or shed, this is a perfect idea of how simple your project can be. Just get an LED bulb to minimize the energy storage needs. How much solar do you really need to integrate for a light? Keep it simple and low cost.
Step 1: Determine how much power you use or need. A solar integration will likely be a combination of battery operated devices, battery chargers, and the actual solar panels you typically think of, hence the integration part. This is a combination of multiple power sources to get you to a reasonable power goal. Plan for the bare basics because practically, it’s not reasonable to power all of your home off a solar array. The average home simply isn’t efficient enough and runs entirely too much electric at one time. Things like an air-conditioning system would almost instantly kill your power supply. While it is possible to power your entire home off solar, it ain’t happen’n w/ the a normal person’s budget.
To get an idea of how much power each device is pulling, plug it in under the most accurate possible circumstance with a power meter. I’ve used the Kill A Watt in the past with good success.
Side note: We’ve gotten to the point in technology where fencers come in a wide variety of pre-made solar options, w/ a good battery that will keep them strong overnight, so we won’t even worry about addressing that. If you’re looking for a good fencer, I’ve seen enough reviews to lean toward the Parmak. They all say that they shock through wet weeds and brush, but don’t believe them, keep your fence path cleared. The fact of the matter remains, electric finds the fastest possible way to ground. If a wet piece of brush is it, then that’s the end of your electric. And the up to 25 miles, I’d cut that down to a max of 20 and see what kind of power you’ve got at the end, probably not much. If you’re running a double or triple line, that makes double or triple the distance as well.
Estimating power usage in absence of a Kill A Watt meter. Multiply the advertised wattage of your device (40 watt TV) by the number of hours you use it per day. (40W x 2 (2hrs/day)= 80 Watts). While it’s never as clear and simple as that, that is a good estimator. Your Kill A Watt is worth the $19 to more effectively plan your system. Also, it isn’t a bad idea to have only an outlet for each device you plan to power, then uplug them. That phantom load electronics pull to keep memory is a real battery killer at night.
Once you figure out how much power you need then you can start looking at systems. Warning, they get real pricey, real quickly. This is one reason you may want to think about only powering the things you really need and adjusting your habits to avoid certain aspects. For one instance, if you can prep dinner early and use a deep freeze on a refrigerator setting, you’ll save a ton in electric and only need to power it during the day, eliminating your need for batteries, depending on sun and solar array size.
A significant consideration is the length and severity of your winters. Long dark winters like Alaska, or even the North East US make solar a lost cause. Also, even if you only need summer seasonal solar, but live in an extremely overcast region like PA, you’re simply not getting enough sun to reliably charge your phone. Don’t waste the money, look at other options, like a generator or possibly a wind mill. On a dark winter day you’ll be lucky to see 10%-20% of your system’s total capacity, in which case you need to add more panels and batteries. $$$$ Think about it before you start down this expensive hobby of a path.
Step 2: Actually getting the magical panels that collect this Vitamin D falling from the sky. There are 3 types of solar panels (AKA photo-voltaic cells (PV cells) or PV panels). The cheapest, amorphous silicon, followed by poly-crystalline in the middle, and mono-crystalline the most efficient and most expensive. Amorphous silicon panels are pretty cheap, and are affected the least by shadows, however they’re really inefficient because of how much space they take up to collect the same amount of power. These are most like those little cell phone charging pack you get w/ backpacking and camping gear. You’ve really got to get it in direct sunlight for a while to charge your phone. Just not adequate for a solar integration project due to the lack of actual power this tech provides. They’re also a great deal heavier. Poly-crystalline panels are a bit more efficient, only a little more expensive, but I still wouldn’t settle for them. Mono-crystalline panels are the most efficient, but expensive. Unfortunately, due to the wiring, they’re extremely sensitive to light/shadows. If you’ve got some tree foliage over your solar collection area, don’t even waste your money with these. Either get the tree trimmed or go w/ a less efficient, but cheaper panel. The Renogy 100 Watt panels are the most recommended by quality and reliability. They’ve also got a very competitive price. Be VERY careful buying cheap knock offs, you get what you pay for, especially in this industry.
Your solar integration needs to be well thought out on not all willy-nilly or you WILL regret it.
Side Note: System Voltage can be a big deal, though I tend to side with 12V, it’s just more common than the 24V or 48V. Don’t complicate your life anymore than necessary. This does require some different electric devices if you don’t want to get an inverter.
Step 3: Now we take a look at the charge controller. How many amps of charge controller do you need? Divide the Solar Panel Watts by Battery Voltage. So, if you have 300W of solar and a 12V deep cycle marine battery bank, 300W/12V = 25A so would want to use 30A charge controller. Your battery Ah capacity needs to exceed this (25A estimate).
The best recommendation for a charge controller is a Maxium Power Point Tracking 3215RN (MPTT) charge controller if you want to really take care of your system and keep it around for a long time. You’ll typically get close to 30% more power and you can run your panels in chains at a higher voltage, which equates less cable and higher voltage and power less loss. The power loss during transmission is the biggest reason renewable energy has taken so long to become viable. A solar farm in the middle of the desert doesn’t do jack for anyone 100+ miles away because of all the loss during transmission across all that wire.
Side Note: PWM (Pulse Width Modulation) controllers are a cheap alternative and can be used if you’ve got a low need system, but severely lack in efficiency and they’re not the best for your batteries.
Step 4: Batteries are the next important step in your solar integration project because you probably don’t only want power when the sun is hitting your panels at full capacity. Flooded batteries have a long life and are cheap, but require maintenance, like a top-up of acid a couple of times a year. Depending on your needs and the battery bank size, you can use 6V or 12V batteries and link them together to form a large bank. If you want to build a giant system because you’re so freak’n rich, you can always look at 2V traction batteries.
For most of us, sealed batteries are the go to because we don’t want to burn our system up because of an oversight in something that just doesn’t rank up there in priorities, until it does. They’re a lot more expensive, but worth it in my opinion.
Nickel Iron NiFe batteries are the longest life options and are totally tree hugger friendly if you also love the environment. They’re supposed to have a lifespan of 40 years, but I’d estimate that down to 30 at best, still making it an amazing long time. Something that great, you know it’s mega expensive.
In terms of constructing a bigger battery bank, 6V or 12V batteries wired together in a bus bar rather than just linking them together is a lot better. It spreads the load more evenly across the bank which greatly helps their lifespan.
If you plan on running devices off of AC power (i.e. use normal wall plugs), you will also need an inverter. There are broadly two types of inverters: modified sine wave and pure sine wave. Pure sine wave inverters give you power that is closer to city power, but these inverters tend to be more expensive ($150+ for a 600W inverter). Modified sine wave inverters can be much cheaper ($30+ for a 400W inverter), but some devices may not work, or work well with them. Note also that inverters have 80-90% efficiency, which means you lose some power in the DC to AC conversion.
If you’re looking for full Solar integration of your regular electronics, you need an inverter
Step 5: Now comes the fun part, hooking up your regular electronics. For this you need an inverter. This is what converts the DC battery power/solar panel output o 120V AC power. (WHICH was invented by Nikola Tesla, BTW) Don’t go over buying here, but figure out realistically how much power you need from your inverter. If you’re just running a laptop or some small electronics like that, a 350W inverter is fine. If you want to run larger devices, you want to use a large 3Kw inverter, though I like to start with the middle ground at around 800Kw Cobra CPI 880. A Pure Sine Wave inverter provides a smooth power to your appliances to ensure your electronics aren’t damaged. I’ve seen some rumors that a modified sine wave inverter will damage electric motors, so it’s probably best to go with a pure sine wave inverter if you’re running something with a motor.
All that being said, I don’t see much reason to have an on-grid solar integration system. You have to connect it to you main electric system and lose power when everyone else does so the technician doesn’t get fried when working on the lines. I understand the desire to decrease your electric bill, but it just doesn’t make enough sense for me. I’m certainly open to differing opinions and perspectives though.