If there is one mistake that is made over and over and over it is sizing your solar electric system too small. We all dream of living in the peace and quiet, off the grid, cooking over a rocket stove and washing our laundry on a wash board.
We have images of brewing our coffee in a glass coffee percolator on our propane range. Surely we won’t need that much electricity?
Wrong? Most of us have lived with the luxuries of modern living and adjusting to not having those luxuries is NOT easy.
It might sound romantic but when you have three or four children dirtying laundry faster than you can scrub it clean and hang it on the clothesline the romance is gone.
Be realistic. There are certain appliances you will probably not want to live without.
An electric coffee maker for example may sound like a huge energy pig but when you consider it is only operated for a few minutes at a time, it does not usually use that much power.
Ice boxes were a necessity a few generations ago but now that we have efficient refrigerators, it does not make sense to cut and store ice all winter for your ice box in the summer.
If you have a special someone in your life and/or children sit down and think about what you can live without and what you can’t live without. My wife requires a hair dryer while others may not. We use air conditioning in the summer as we have plenty of extra power in the summer but many live without A/C and don’t seem to miss it.
Make a list of every appliance you will want to have in your home or cottage. For example:
WiFi Internet Router
Clothes Washer etc.
The next step to figure out what each item consumes instantaneously, per hour, per day, per year, or per load (washing machine or dish washer) and then figure out how often you will use the appliance.
You can get this info from the manufacturer, the government or by using a meter such as a Kill-a-Watt meter.
Example #1: You purchase a refrigerator that consumes 300 kWh per year. Divide this by 365 days in a year and your fridge will use .82 kWh (820 watt hours) per day.
Example #2: You purchase a hair dryer that consumes 1200 watts (or 1500 watt hours per hour). You are going to operate the hair dryer for 15 minutes per day or 1/4 of an hour (15/60 mins). Multiply 1200 watt hours by 1/4 and your hair dryer will consume 300 watt hours per day.
Example #3: Your front loading washing machine consumes 140 watt hours (.14 kWh) per load and you will use your washer 9 times per week. First multiply 140 watt hours by 9 to get 1260 watt hours (1.26 kWh) per week. Divide this by 7 days and your washer will need 180 watt hours (.18 kWh) per day.
Example #4: Your WiFi router uses 23 watts and will be on 24 hours per day. Multiply 23 watts by 24 hours and your new router will take 552 watt hours (.552 kWh) per day.
Add all of your electrical needs to get a daily requirement and then double it!
You read that correctly double it!
Now use this figure when you design your battery bank and solar array system. Solar arrays do not make anywhere near their maximum rated power output and batteries will last far longer when not cycled deeply.
Almost everyone else calculates their power needs and they design the smallest solar array and battery bank that will operate it.
This never works! Don’t be like them!
Think about it. You design your solar array to make just enough power to run your daily loads. Three days go by without sun. Now your battery bank is deeply discharged. The next day is a beautiful sunny day but your solar array just makes enough to operate your regular loads. There is nothing left to bring the batteries back up to a full state of charge. Now your battery bank is in a perpetual state of deep discharge, the power will go out regularly and you will be another person who tells folks to stay away from solar power as it does not work.
Please be one of the successful off gridders and don’t believe what you are told unless you are getting info from someone who has lived off grid for many years.
Solar companies that do not use their own products are constantly making promises they can’t keep. It is not their fault sometimes. Sometimes they just don’t know any better.