Stand-alone Solar Applications

The sun charges us up in more ways than we can count. It is, of course, the mood enhancer when we wake up to a sunny day.

When most people think of solar energy, though, they think of panels on the roof, generating electricity for all their household needs. This is a great option, but it is the most expensive option, kind of like investing in a car for all your mobility needs.

If you only need to go to the corner store, there are more affordable options of getting there, like walking or biking. It’s the same with solar; not everyone may need a rooftop system big enough to power all the household’s needs. A more task-oriented stand-alone system could well fit the bill.

A local bike shop has installed 3 ceiling fans powered by 2 panels set up as awnings over their front door, needed exactly when they’re busiest – sunny days! Read about the fan & panel installation and afterward.

Finding the alleyway too dark to approach the garage doors at night, one local household installed solar floodlights. These can soak up the sun during the day, and automatically come on when sensing motion after dark. Easier wiring, one time cost without adding to the electric bill – what’s not to like?

Before you head out to the stores, here’s a review of solar flood lights.

Most of us need a desk lamp only in the evenings. This could be another perfect application – a solar desk lamp, good for several hours into the evening.

Our Friends at Germantown Monthly Meeting manage a local community garden, the Old Tennis Court Farm. 

At this garden, you’ll find panels on their shed roof, providing electricity for a well pump that fills up water barrels for use by gardeners. Over time, they’ve added an inverter offering an AC power source to the garden. And invested in an electric lawnmower and weed whacker that could be recharged and available for use by all gardeners.

Search for “solar charger” and you’ll find an array of products designed to charge cell phones and other USB devices, AA and AAA batteries, even laptops and refrigerators. For those looking to light up a detached garage or shed, and maybe a power tool, one of Goalzero’s Yeti models with a lead acid battery, packaged as a kit with solar panels could be just the ticket. It can also be used instead of a generator for emergencies.

Another family in our neighborhood managed to run their “media room” on sunlight pouring through the windows. They kept all all the components inside, simplifying the wiring. With components from Harbor Freight, a 100W panel charging a 12v 35a battery suffices to run the TV, computer and sound system well into the night. All for under $500.

So think of your electricity needs. We’d love to hear what dedicated uses you’ve come up with for sun-charged electricity. Share your project story with us at nwphlsolar [at], and have a solar-powered day.


After a rough start, I now love our rooftop PV system

It’s been over 3 months since our rooftop system has been hooked up to net metering. I remember the day, October 31st, 2017 when our utility (PECO), replaced our old meter with one that could read the flow of electrons in both directions.

The installers got the panels onto our roof in early August. But to get the generation from our panels interconnected with the grid took some time. This was critical, because we wanted net metering – credit for excess generation that was fed back to the grid.

Why the 3 month delay? The power line to and from our house could have high voltage, said our utility. Meaning sending homegrown electrons out to the grid could be unsafe. The recommendation? Join a pilot program to use an inverter that would limit the voltage we’d push onto the line.
We jumped on this suggestion. But, the initial settings caused the inverter to turn off when voltage hit 253 Volts for one second, taking 5 minutes to come back on. This happened so often (663 times in a 2-week period, for a total of 55 hours of lost generation) that I began dreading sunny days and system shutdown. In fact, our system appeared to work better on cloudy days. 
To share my frustration visually, take a look at the 2 charts below showing solar production throughout the day. The one on the left is our system; the one on the right is a neighbor’s, on the same day. Our system kept shutting down, right at mid-day, wiping out the beautiful green hump of solar generation that the neighbors saw.

It took a few phone calls with both PECO and our installer, and a re-reading of the PUC regulations, to discover that a setting change (power down the system only after a full minute of high voltage, instead of one second) could resolve this. That made all the difference. Now I’m in love with sunny days and my chart looks more like my neighbor’s.

Our system has been running nicely since mid-November, about 3 winter months. From that date through the end of February,  we generated 1,604 kWh of solar electricity. Our household used 512 kWh of that before it went to the grid, and we imported 1,068 kWh from PECO, mostly at night, for a net export to PECO of 24 kWh. Agreed, this is a tiny amount, but this was over the winter! Given that generation is expected to be much higher in other seasons, this should allow us to gradually replace gas appliances to electric, and eventually charge an electric car.

How big is our system? A total of 29 panels, 12 on the roof facing southeast, and 17 on the rear southwest roof, at a few different angles on an 1880’s Victorian with steep roofs. We selected 335 Watt panels, for a total system size of 9,715 Watts (9.7 kW). Curious what this looks like? Take a look at the time lapse photography of the installation.