What Can You Do with a 100 Watt Solar Panel?


Practical uses for a 100-watt solar panel

Let’s be blunt: a 100-watt solar panel is actually pretty small. You’re not going to power your whole home with a 100 watt panel. For reference, solar panels for rooftop installations typically fall around 260 to 300 watts – that’s 3 times as big as a little 100 watt panel. Solar panels for utility-scale installations or large businesses are even bigger!

So just how big is a 100-watt panel, and what can you do with it? Let’s take a look.

How big is a 100-watt solar panel?single-solar-panel

As we already mentioned, a 100-watt panel is much smaller than the typical panels you see up on roofs, both physically and in the amount of energy produced. These smaller panels are used for situations that don’t need a lot of electricity – think RVs, campers, exterior lighting, and off-grid sheds or other buildings.

First off, a typical residential panel is around 3 feet wide by 5 feet long – physically too big to install on the roof of a camper and a bit too big to discretely install in your back yard. 100 watt panels, on the other hand, are only about 3 feet long by 2 feet wide (like the Renogy 100 watt panel), making them much easier to subtly add to your back garden or RV’s roof.

A 100-watt panel produces 100 watts of electricity in a single instant. In perfect conditions, it could power five 20 watt light bulbs instantly (5 x 20 watt = 100 watts). If you left those light bulbs connected to the solar panel for 1 hour, the panel will have produced 100 watt-hours of electricity (100 watts X 1 hour = 100 watt-hours) and the light bulbs will have consumed that 100 watt-hours.

In the real world unfortunately, a 100-watt panel will produce less than 100 watts thanks to clouds, rain, dirt, dust, and everything else that can block sunlight. Also, the other components of your installation aren’t 100% efficient. You’ll lose electricity as it flows through wires, safety disconnect switches, fuses, and your inverter (if you have one).

The National Renewable Energy Lab, in their solar calculator PVWatts, automatically drops the electricity production of any system by 14% to account for all these losses.

Exactly how much electricity your installation will produce depends on your location. Let’s actually put PVWatts to use and see what kind of electricity we can expect from a 100-watt panel in different cities:

As you can see, a 100-watt panel in Tucson, AZ, produces about 60% more electricity than the same panel in Seattle, WA (no surprise there). It is a bit surprising, however, how close the production is for Chicago and Tampa. Even though it’s cold, Chicago is still a good place for solar!

Of course, if you needed more electricity, you could simply connect 2 or more panels together. Adding another panel doubles your electricity output! You’ll just need to make sure all your other components can handle the extra energy safely.

Now we know how many kilowatt-hours of electricity a 100-watt panel can produce, but who really understands what 177 kilowatt-hours actually means? Let’s look at a few real world examples to see what a 100-watt panel can power.

What can I power with a 100-watt panel?solar-panel

Just for the sake of ease, let’s take all the varying productions above and find the average. This leaves us with 140kWh per year for an average 100-watt panel.

What can we power with 140 kWh hours? We’ll give you a couple examples:

A 32” LCD TV needs about 60 watts of electricity. Let’s say you watch 5 hours of TV a day (sadly, that’s the average in most US households). Let’s do the math: 5 hours X 365 days x .06 kW (ie 60 watts) = 110 kWh per year. With a 100 watt panel, you’d actually have about 30 kWh left over!

Today’s modern TVs are actually amazingly efficient, so let’s look at another example of something that’s, well, not so efficient: the hair dryer.

You wouldn’t think that a little hair dryer uses that much electricity, but you’d be wrong. The average hair dryer uses an astounding 1,875 watts – that’s over 3,000% more than the TV above! Hey, you need a lot of energy to produce all that instant heat. Time for the math:

Say you use your hair dryer – on the highest setting – for 10 minutes every morning. Each day, that’s 319 watt-hours of electricity (1875 watts X .17 hours = 319 watt-hours/day), adding up to 116 kWh each year. So, even though your hair dryer uses an insane amount of electricity (for what it is), you’d have enough power from a 100-watt panel to cover it simply because you use it so infrequently.

The hair dryer, though, raises an interesting point. Compare the hair dryer’s wattage to the solar panel’s wattage. The hair dryer needs 1,875 watts to run. The solar panel can only produce 100 watts. What does this mean?

We’ve come across the issue of the solar panel’s capacity. Yes, over the course of a year, the solar panel can produce enough electricity for you to use your hair dryer, but you’d need a battery large enough to store all that electricity and put out at least 1,875 watts of electricity in a single instant.

If you simply connected the hair dryer to the solar panel, the solar panel couldn’t produce enough ongoing electricity to power the hair dryer. The solar panel’s capacity isn’t high enough. Even in a perfect situation, the solar panel can only produce 100 watts of electricity.

You can avoid this issue by connecting your small solar panel to a battery, allowing you to power gadgets that the solar panel alone simply couldn’t handle.

A 100-watt solar panel is great for powering one or two gadgets around the home or charging a small off-grid set-up where energy needs are low (like in an RV or camper).

As we mentioned before, a single 100 watt panel’s power is pretty limited, but you can certainly connect multiple small panels together to produce more electricity. It just doesn’t produce enough energy to cover, say, a hair dryer AND a TV. But if all you need is a bit of electricity to power a few lights in your garage shop, it’ll do just fine (especially with a battery).

Image Credits under CC License via Pixabay – 1, 23

  • by Ryan Austin
  • |
  • July 31, 2017
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