Have you been considering adding an off grid solar system to your preps? Well before you jump in and start buying a bunch of gear, ask yourself why solar? What is the need you hope to fill?
Are you looking for back up power during an outage?
Looking to be environmentally friendly?
Looking to reduce your energy costs?
Looking to be more self sustaining?
Looking to go completely off the grid?
Looking for a quiet option to that noisy gas generator?
We all have different reasons for considering solar, some which may be fairly simple and easy to accomplish while others may prove to be much more costly. You can get started with a small off grid system for under $1000, but a full grid tied or off grid system can cost $20,000 or more. Only you can decide if solar is a good option for you, but hopefully we can provide some insight to help you decide.
Let me start with a little disclaimer: I have never been a big fan of ‘alternative energy’ because often the cost outweighs the benefit. A $100 million solar project at Fort Hood is estimated to save the military $168 million over 3 decades, so over 20 years to recoup the costs while supplying only 50% of the needed energy – not great. There’s a reason that eBay has hundreds of used solar products for sale! That being said, I do think with the recent improvements in efficiency that solar is a viable option in some scenarios.
Grid Tied vs. Off Grid
A grid tied system is a solar system that is tied to your electrical panel and supplements the power coming to your house from your local power company. It supplements your power instead of replacing it. When the sun is shining you may be able to run your home completely on what you are producing (depending on the size of your system and how much energy you use), while using energy from the grid at night or on overcast days. Note: in some areas your electric utility may actually pay you for excess energy you produce that feeds back into the grid. The downside of grid tied, aside from the initial cost, is that unless you also have a storage bank of batteries which most do not, then your system is useless during a power outage.
Off grid solar is just what the name implies – generating and using energy independent of the grid. Off Grid systems range widely in size and cost, depending on the size and capability. For example: we started with a small Renogy 200 watt 12V ‘complete system’ for just under $800. The same company sells a 4500 watt 48V system for just under $6000. as I said; cost varies widely. Note: most small off grid systems are 12V due to their simplicity and low cost.
So back to our original question: what is the need you hope to fill?
Our goal was to have back up power separate from our noisy gas generator and be able to run a few small lights and devices on a daily basis to reduce our energy costs. To size your system correctly you have to understand the energy needs you are trying to replace. We used a Kill-O-Watt meter to test various appliances and gadgets around the house; a simple device that measures usage in watts, volts, amps and even kWatt hours and can estimate how much each device is costing you to run. Here’s a chart of common devices and their usage: https://www.wholesalesolar.com/solar-information/how-to-save-energy/power-table
We decided to start small and expand if we liked the results, where you start will depend on your budget and level of commitment. As stated before, we purchased a small 2 panel 200 watt 12v system for just under $800. We chose this system for it’s simplicity, cost and the fact that it came with everything we needed to get started on a small scale. 2 panels, 30 amp charge controller, battery, 500 watt inverter and all the cables, fuses and connectors. The setup was easy, even for beginners like us, and we were creating our own electricity within a couple of hours. This is the system we purchased.
Simple layout, simple setup, but limited capability. We were now able to run our PC, laptop, modem, router and several LED lights independent of the grid, but larger appliances were out of the question as the 500 watt inverter just didn’t have the capability to run the microwave or other similar appliances and would leave us dependent on our gas generator to run those items. We decided to expand the system by adding 2 more 100 watt panels (now a total of 4) to increase production and 1500 watt inverter to handle some appliances. So far so good. Note: if you are wanting to run sensitive electronics such as a laptop be sure to purchase a ‘pure sine wave inverter’ as it mimics the power coming from the grid. I should note that there are many different panels available in varying voltages all with one primary difference – monocrystalline and polycrystalline. Monocrystalline panels claim to be slightly more efficient and produce with less sunlight while polycrystalline are slightly less expensive. We currently have a mix of both and have found little difference.
Limitations: production and storage. Production is limited primarily to the number and type of panels you have and how many panels your charge controller can handle. Storage is limited by the type and number of batteries you have. Oh, but don’t forget about sunlight! A system functioning nicely on sunny days can become useless after a couple of overcast days and not all hours of sunlight give maximum production. See chart for more info: Sun hours available.
The system unexpectedly proved it’s worth one stormy March afternoon: Read that story here.
We have added a 2nd battery to our little system to increase run times, to do this in a 12 volt system you must run the batteries in parallel (positive to positive = negative to negative) to increase the amp hours while keeping the voltage the same. Batteries should be of the same amperage and approximate age for best results.
Note: your charge controller and inverter must be connected to the same battery terminals as seen in the picture.
Warning: this can become addictive!
In hindsight we should have started with a larger system, or built one from individual components, but again, this was a learning experience for us. We are replacing the original charge controller with a 60 amp unit giving us the ability to run ten 100 watt panels generating up to 1000 watts while staying at 12 volts. Aside from adding more batteries for storage, our little system is maxed out. You can go larger, but that would require going to a 24 or even 48 volt system.
We spent countless hours of research before starting this project and still made some mistakes along the way. One resource we found to be particularly helpful was a series of YouTube videos from the Tin Hat Ranch. You will find the links below.
Hope you found this helpful!
Hope for the best, prepare for the worst!