Ted & Nancy’s Excellent Rooftop Solar Adventure

Many people assume mounting a rooftop solar system on their home is a big deal. You need a solar company, trained installers, financing, permitting, and a blessing from your local utility company. But sometimes, if the moon and stars align just right, you can do it yourself.

Ted and Nancy are my neighbors in Florida, where “snowbirds” gather every winter to escape the cold in the Northeast and upper Midwest. Lots of Canadians make the trek south as well. But there is a corollary to that term. There are many Floridians who escape to cooler climes to avoid the blistering heat of summer. Let’s call them “sunbirds.” My wife and I decamp every year in late June to Connecticut, where we visit family and friends and renew our acquaintance with Cape Cod, Ogunquit, and Vermont.

Ted and Nancy head north to New Jersey to spend the summer at their lake house in a seasonal community. It sounds rather idyllic, from what they tell me, except for one thing. None of the 80 or so homes around the lake are connected to the electrical grid. They feature lots of wood stoves, propane cooktops, and gasoline-powered generators, but there are no air conditioned 5,000 square foot McMansions.

This lakeside community dates back about 100 years to a time when people were looking for a place to spend the summers away from the heat of the cities. Originally, tents were the shelter of choice. The Jersey shore is nice, but it can get crowded and expensive if you want to stay for more than a week. Living on a lake offers a sense of tranquility that is hard to find near the ocean.

In the 1960s, Ted’s mother-in-law discovered this summer retreat and began renting one of the 87 campsites dotted around the lake. In 1988 the Kean family — Tom Kean was the governor of New Jersey at the time — put all 600 acres of the campground up for sale. The 87 families who had been paying annual rent for their campsites decided to band together and purchase the land for $2.2 million — just over $25,000 each.

“Everyone had their little wooden cottages built mostly from scrounged materials for years,” Ted told me. “No electricity, no running water. Then the possibility opened up to invest in and improve our plots, subject to strict town ordinances and regular building codes. We were deemed to be a non-conforming use by the town, so much of what we did had to go before the Board of Adjustment for a variance.” They went before the board in 1989 to get permission to rebuild a rickety shack that was located on a great piece of land.

“The Town said we could not rebuild and wouldn’t give us a variance. So we built half of the new cabin in one year, then built the other half the next year, because rebuilding half only required a building permit, not a variance. So we took the long way around but it got us to the same place,” Ted told me, which proves you can fight city hall if you are patient and determined.

A few years later, Ted started a campaign to bring electricity to the community, but the owners voted it down. Not long afterward, the first solar panels began arriving on the market. Nancy’s father became an early adopter 20 years ago when he put two way-too-expensive panels on the roof of a shed. Ted and Nancy installed four solar panels on the roof of their lake house a few years after that. They have been improving and upgrading their rooftop solar system ever since.

A Rooftop Solar Champion

Ted is the informal leader of an off-grid solar power movement among his neighbors on the lake. “I am neither an electrician nor an electrical engineer — just a well-read enthusiast of solar power applications. There are now about twelve PV systems on houses around the lake, some of them quite substantial. Today, no one is asking to be connected to the electrical grid.”

Today, Ted and Nancy have 8 solar panels on the roof of their 1200-square-foot lake house in New Jersey, where they spend about 5 months of the year. Ted installed the panels himself and built the battery storage and control systems as well. The rated output of the 8 panels is 2400 watts. On a sunny day in late June, the system can supply 7 kWh of electricity. That drops to about 5 kWh as the sun gets lower in the sky around Labor Day.

The rooftop solar system powers all the lights, charges computers and other digital devices, keeps the internet router powered, runs the television and other light duty appliances and yard equipment, and keeps the ceiling fans in the house moving. Typically, the home uses between 2500 and 3000 Wh of electricity each day. Needless to say, he and his family are keenly aware of their energy usage in a way that people connected to the grid seldom are.

Solar & Energy Storage

Until recently, energy storage for the rooftop solar system consisted of 6 AGM 105 amp/hour lead acid batteries mounted in the shed. Ted has kept them properly maintained since they were installed five years ago. They are working fine but were getting near the end of their useful service life of about 900 charge/discharge cycles. Replacing them with new lead acid batteries would cost about $1800.

Two new 280 amp/hour lithium iron phosphate batteries from EcoWorthy cost $800 on Amazon, so Ted ordered and installed them this year. Not only were they less money, they are rated for 6000 charge/discharge cycles. At 150 days a year average occupancy, these new batteries could last for about 40 years!

There are other important advantages to lithium ion batteries. The old lead acid batteries don’t function well below 50% state of charge. The new LFP batteries can function all the way down to a zero state of charge, although doing so on a regular basis is not recommended. As a result, more of the solar energy captured during the day can be accessed after the sun sets each day.

“With the new batteries, I have nearly doubled my daily power accessibility due to the high depth-of-discharge tolerance of lithium batteries,” Ted told me. “I don’t expect to have power concerns during the hot and humid days of August when my visiting children and grandchildren are running fans all night long!”

The battery upgrade was the perfect time to update the inverter as well. The old inverter supplied electricity at only 120V. The property has a deep well with a 240V submersible pump. Until now, Ted had to fire up the gas-powered generator to power the pump to fill the water storage tank. That generally wasn’t a problem unless you were standing in the shower when the water in the tank ran out!

Ted replaced his 5-year-old 120V pure sine wave inverter (2500W steady state, 7500W surge), with a 120/240 split phase pure sine wave inverter (4000W steady state, 12000W surge) from AIMS Power — $1370 online with free shipping. The total cost for the battery and inverter upgrade was more than it would have been to replace six lead acid batteries, but now there are no worries about running out of water at an inconvenient time.

I do words; Ted thinks in numbers. He loves to calculate stuff, such as the cost per kWh of his old and his new batteries. Here are the numbers he shared with me:

• Lithium batteries cost $800 for the two. Lead acid batteries cost $1800 for six.
• Cost per accessible kWh (DoD 60%) for the AGM batteries is $1800/380kWh=$4.74
• Cost per accessible kWh (DoD 90%) for the lithium batteries is $800/504kWh=$1.59
• Cost per rated charge cycle for the six AGM batteries $1800/900=$2.00.
• Cost per rated charge cycle for the two lithium batteries is $800/6000=$0.13

Unlike the old lead acid batteries, the new lithium batteries have a Bluetooth-enabled Battery Management System app for reading battery status and available capacity. “It’s pretty neat to be able to check the status of my batteries anytime on my phone, even when I am not in New Jersey,” he says. “Since the upgrade was completed in early June, the system is performing flawlessly!” It may not be possible to put an exact price on peace of mind, but it is worth a lot.

Ted freely admits he is not an electrician or engineer, but all the information you need to design and build a rooftop solar system of your own is available online or at YouTube University. Don’t believe it? Check out this video, one of many available online.

It helps that Ted and Nancy’s lake house is not grid-tied, which simplifies the whole process, since there is no need to get approvals for the rooftop solar system from the town or the local utility company. No expensive automatic transfer switch is needed either to isolate the system from the grid during power outages. It’s amazing the things we can do when we put our minds to it!