Last spring I installed solar power in my Off-Grid Tiny House in Montana. First, I did a lot of research on electrical engineering and as you can imagine, it's pretty complicated. No one had exactly the same setup that I wanted so I had to pretty much design the whole system. This was good though because I had the chance to learn things that have already come in handy on other projects.

When you design any solar system, you need to first establish what your needs are and the reason you want solar in the first place. I use my tiny house/cabin as a getaway and vacation spot so I really didn't need much. The main things I wanted were lights, a mini fridge, and the ability to charge cell phones and power tools. The reason I wanted solar is because bringing power to the property would have costed me around $4300 and then $10 a month base charge plus consumption. I also liked the idea of being self sustaining and self reliant. I set a budget for $2000 and started designing.

First, I figured out what my daily energy demands would be in watt hours.

The mini fridge I decided to go with was the EdgeStar CRF321SS 3.1 Cu. Ft. It had a good balance of affordability and energy efficiency. According to it's Energy Star Rating, it uses 270 Kw/h per year, or 740 WATT HOURS PER DAY.

The 12V light bulbs I bought use 7 watts each and I figured I might have two bulbs on for an average of 6 hours per day. So, (6 hours)(2 bulbs)(7 watts) = 84 WATT HOURS PER DAY

My Ryobi power tool charger uses 85 Watts and I might use it about two hours a day when I'm working. (85 W) (2 HR) = 168 WATT HOURS PER DAY.

Add this up, 740 + 84 + 168 = 992 Watt Hours / Day. I rounded it up to 1000 W/Hrs a day.

Second, I designed the solar array.

I wanted a solar array that could charge me up to 100% on a cloudy day during a regular days usage. To do this I decided I would design a system that would recharge 2000 W/Hrs on a sunny day. On a typical sunny day, a 100 Watt solar panel will produce 500 watt hours of electricity. I decided to use the HQST 100 Watt 12 Volt, meaning that I needed 4 of these panels to get to my 2000 W/Hr per day goal.

Third, I designed the battery bank.

I wanted a battery bank that could store three whole days of energy on one charge. This would mean over 3000 Watt/hrs of electricity. Battery storage is usually rated in Amp Hours. You multiply your Amp Hours by the system voltage to get Watt Hours.(Amp Hours)(Voltage) = Watt Hours. To get from Watt Hours to Amp Hours you divide Watt Hours by Voltage, (Watt Hours)/ (Voltage) I wanted a 12 Volt system, so (3000 W/Hrs) / (12 V) = 250 Amp Hours. This means I would need at least a 250 Amp Hour battery bank to meet my requirement.

As far as types of batteries, there are plenty of different options. I could do a whole post on the pro's and cons of each type, but I won't now. Let me know if this would be a helpful topic. After hours of research, I decided to go with two 155 Ah Vmax AGM Deep Cycle Batteries. This gave me a total of 310 Amp Hours of storage or 3720 Watt Hours.

And last, I figured out what components I would need to hook everything up.

For this part it might be easier to just show you my video below. Let me know if you have any questions!

Here are most of the Amazon links to the parts I used:

Solar Panels - http://amzn.to/2j7bbYf
Batteries - http://amzn.to/2zW53MK
Charge Controller: http://amzn.to/2jCqzeA
12V Wall Outlets - http://amzn.to/2jCgsGA , http://amzn.to/2nkAQku
12V Light Bulbs - http://amzn.to/2AoqG5h
Fuse Box: http://amzn.to/2AooM4O
400W inverter - http://amzn.to/2kch9u2
150W Inverter: http://amzn.to/2iCcp0D
Mini Fridge - http://amzn.to/2jCK7zk