When it comes to living off the grid and being self sufficient, having a strong understanding of your renewable energy options is very important. It is possible to live without electricity. I did it for over 15 years. However, having a source of electricity was a game changer for me. I now power two cabins, a chicken barn and a 600 square foot green house all from solar energy. But I started out simple and first discovered just what I could power with a 100 watt solar panel.
But in order to go big, you must start with the basics. Since some of my most recent projects have involved a 100 watt solar panel, that is why I’ve chosen this as an example. Then you can build on the basics. So, let’s first develop an understanding of what you can power with a 100 watt solar panel.
A 100 watt solar panel is inexpensive, easily available, and best of all it is portable. It has become a popular choice for RVs, camping, recharging portable devices, as well as other things. Despite this growing popularity, this type of panel has its limitations. It is smaller than the normal residential solar panel. Additionally, you are only going to be able to power smaller devices.
The 100 watt solar module that I recently purchased measures approximately 47 inches long, 21.5 inches wide and is 1.5 inches thick. It was produced my Renogy Technology.
Dimensions will vary according to the model and manufacturer. It is important to shop and compare depending on where you want to place the panel.
A quick shopping tour revealed that a 100 watt solar panel ranges in price from $90 USD to $140 USD.
You can purchase just the basic solar panel if you wish. But, since the 100 watt panel only produces a small amount of power, it is better to purchase a battery to store the excess energy to be used as needed. This of course means you will need to purchase a charge controller, cables, and brackets for mounting.
Additionally, if you want to power devices, you will need a small inverter. The inverter converts DC power from the batteries into AC current which will power your devices.
It is less expensive to purchase a package deal. I found 100 Watt solar panel packages for around $160 USD.
Two 100 Watt Solar Panels: $228.97
Mounting brackets: $19.99
Charge Controller: $49.99
10 AWG extension cables: $20.58
Now, I did not include the cost of the inverter because I used a salvage piece of equipment that I already had. I also did not include the cost of batteries because I already had some on hand. But, here is examples of typically cost.
300 watt inverter: $27.99
1100 watt inverter: $84.97
Deep cycle batteries: $41 to $280
Batteries have a huge range of cost depending on the rating of the battery.
I used to be naive enough to think that in order to produce electricity from a solar panel all you had to do was put the panel out in the sun and plug things in. But, I soon learned that it is just not that simple.
A 100 watt solar panel is rated to produce 100 watts under optimum conditions. What this means is peak sun and provided that the solar panel is at the optimum angle to the sun. However a good portion of the day, the solar panel will not be exposed to full sun and will be producing much less than 100 watts.
Additionally, how much sun light you get depends on your latitude and local climate. For example, Colorado has an average of 300 sunny days per year. But, Portland, Oregon only has an average of 144 sunny days per year.
When designing a solar array for a residence, the size of that array is based on 4 hours of peak sun per day, referred to as watt hours (Wh). Consequently, to be conservative, you should figure a maximum of 400 watts of energy produced per day.
If you want a small solar array that is still portable, you can purchase more than one panel and connect them together. This is what I did. See my post titled A Simple Solar Project . However, you are still limited in the amount of energy you can produce due to the size of the panels. For example, the average solar panel for residential application is rated somewhere between 285 and 360 watts. Consequently, assembling a large array out of 100 watt solar panels is not very practical or efficient.
Yes you should if you want to store excess energy for later use. But it is important to have the appropriate size battery. It is best to choose a battery that will store about twice as much energy as you produce. If you produce 400 Wh each day (100 watts of energy x 4 hours = 400 Wh.) then you need a battery that will store 800 Wh of energy. However, batteries are rated in amp hours.
The way to covert this is by using the following simple equation;
800 Wh divided by 12 volts DC = 66.67 amp hours.
So, you need a battery bank that is rated for at least 70 amp hours.
There are multiple things you can run off of a 100 watt solar panel. But a better question to ask is just how long you can run a particular appliance from the energy produced from a 100 watt solar panel?
Let’s look at a couple of examples:
Based on producing 400 Wh/day:
Laptops 60 Wh = 6.15 hours of run time
LED light 10 Wh = 40 hours of run time
WiFi Router 6 Wh = 66.7 hours of run time
DC vent fan 80 Wh = 5 hours of run time
iPhone 5.85 Wh when fully charged = 68.4 hours of run time.
The easiest way to figure this out for each appliance is too look at the wattage rating. If an appliance is rated at 10 watts that means it uses 10 watts per hour. Ten watts for one hour is 10 Wh. Ten watts for two hours is 20 Wh.
The answer is yes. But it depends on what you want to accomplish.
If you want a small portable array to power a few devices then a 100 watt solar panel is a good choice. If you want to recharge the battery system on an RV or have some basic electricity on a camping trip, then a 100 watt solar panel is a good choice. If you are trying to power your residence, then this size of a panel would not be a good choice. Again, it depends on what you are trying to accomplish.
Go off grid and live well,
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