sonnenCore: Lower Priced Versatility

New sonnen Battery Makes Home Energy Storage More Affordable and Flexible

Just in time for the holidays – and for the final year of federal solar energy tax credits – sonnen has introduced a more affordable home battery system.  The new sonnenCore battery has a higher safety rating and much longer projected lifespan than the Tesla Powerall, while featuring state-of-the-art operating modes and power management technology.  Its fully integrated design stores your solar generation for home energy use when it’s the cheapest, and runs your home electrical needs even when the grid goes down.

Solaflect Energy is now taking orders for sonnenCore battery installations.  Batteries placed in operation in 2021, when paired with an existing or new home solar energy system, qualify for a 22% federal solar energy tax credit.  This may be the last time to take advantage of this credit, which is due to expire at the end of 2021.

Sonnen is a German battery manufacturer known for the longest-lasting home storage batteries with plenty of smart metering features.  The new sonnenCore battery sells at a significant discount to sonnen’s eco and ecoLinx lines, while featuring a state-of-the-art energy management system.  Features include computer cloud and phone apps to monitor real-time home energy use from anywhere.  The sonnenCore is also designed for time-of-use load shifting between the home and the grid to maximize savings on your electricity bill.

Other benefits of the sonnenCore home battery include:

  • Right-sized:  The sonnenCore is a fully integrated, 10-kilowatt hour (kWh) battery storage system with the ability to provide up to 4.8 kilowatts (kW) of continuous power output.
  • Fireproof and eco-friendly:  The sonnenCore is a lithium phosphate iron battery that eliminates any possible fire risk posed by traditional lithium ion batteries.  And unlike the Tesla Powerwall, there’s no cobalt in the battery chemistry that would require final disposal as a hazardous waste.
  • Reliable:  The sonnenCore includes a backup power mode that switches the battery on automatically for uninterrupted home power supply when the grid goes down.
  • Durable:  The sonnenCore has a warranty of 10 years or 10,000 discharge cycles (whichever comes first), 8 to 13 times more discharge cycles than competing batteries, and is expected to last for 20 years.  The sonnenCore boasts a 100% discharge cycle – the maximum available – and is capable of storing 70% of its initial out-of-box capacity even when the warranty expires.
  • Built to last:  The sonnenCore will operate at 70% of its rated capacity even after releasing an estimated 58 megawatt-hours (MWh) of power during its warranty period.  By comparison, the Tesla Powerwall drops to 70% of rated capacity after releasing only 37.8 MWh of power.  This means the sonnenCore has the ability to release more energy than the Powerwall over the same warranty period, with less impact on battery discharge capacity.
  • Affordable:  Best of all, the sonnenCore comes more affordably priced, particularly after the 22% federal solar energy tax credit.

Battery features

ChemistryLithium iron phosphate
Total capacity10kWh
Peak power8.6kWh
Continuous power4.8kWh
Depth of discharge100%
Roundtrip efficiency>85%
Warranty10 years
Warranty cycles10,000 cycles
End of warranty capacity70% of initial capacity
Dimensions68” L, 26” W, 11” D
Weight348 lbs

SolarReviews sums up the sonnenCore battery this way:

“The sonnenCore is one of the first batteries that seems like it can really compete with the Tesla Powerwall.  The sonnenCore offers a competitive price, higher safety ratings, and a better warranty than the Powerwall, while still offering state-of-the-art operating modes and battery management technology.”

Solaflect Energy is your home energy management partner.  We’re taking orders for sonnen battery installations this winter that qualify for a 22% federal energy tax credit when paired with an existing or new home solar energy system.  Working together, the power is in our hands to make a difference!

Record Breaking Solar Production

Record breaking production on Saturday from a two-Tracker installation on Bragg Hill in Norwich, VT. These blue bird cold days in winter can really top the charts, and compensate for miserable cloudy days in Sep/Oct/Nov of 2018 that produced 25% less solar than the same time frame in 2017. In contrast, Feb 2019 alone saw 27% more solar production than Feb 2018.

Let It Snow! But preferably on solar that sheds snow quickly!

Solar energy is great, but not so much when it’s covered in lovely white stuff for days on end while the sun is shining.   And that’s just one of the reasons a solar Tracker makes all the difference.  Shedding snow quickly, getting right back to work, and generating 40% more solar energy than rooftop solar.

2019 is the last year to get the full 30% federal tax credit for solar, so now’s a great time to beat the end of year rush and figure out if solar in your backyard or field works for you.  And solar is now possible for little to no money down.

Richmond Middle School Tracker

The Solar Tracker is live at Richmond Middle School. This “sculpture in motion” will reduce the school’s carbon footprint and provide ongoing opportunities for the Upper Valley kids to learn about responsible, cutting-edge renewable energy systems.

Dartmouth College goes solar with Solaflect

Or, “Big Green Goes Green.” From Dartmouth News:

Construction has begun on a state-of-the-art solar panel adjacent to Moore Hall. The panel moves both up and down and sideways to track the sun throughout the day, making it 40 percent more efficient than a fixed unit. Equipped with an anemometer, the solar tracker takes a vertical position in high winds to prevent damage. It’s also designed to shed snow easily. The Norwich, Vt., manufacturer Solaflect has created a lightweight structure that uses less steel than other trackers.

“That makes it cost-effective. It’s really cutting edge technology,” says Timothy McNamara ’78, associate director of real estate for the College. Designed for household use, the panel will provide only some of the energy Moore consumes. But McNamara says it’s also intended to educate passers-by about the benefits of solar power.



WCAX profiles Solaflect installation at East Haven Veterinary Services

WCAX TV-3 in Burlington, Vermont has profiled a recent Solaflect PV Tracker installation at East Haven Veterinary Services. Dr. Sally Schleuter explains that going solar was the logical and responsible choice, especially since the clinic is part of the Vermont Business Environmental Partnership. You can watch the profile below or visit WCAX’s news page. All of us at Solaflect thank Dr. Schleuter for leading the way with solar in vermont.

WCAX.COM Local Vermont News, Weather and Sports-

$1,000 incentive for Vermont electric cars

DriveElectricVT announces

New electric vehicle incentives available to Vermonters

We’re offering up to $1,000 on qualifying plug-in vehicles!

For those in the market for a new car this summer, now is the time to go electric. For a limited time only, we are offering an instant discount off the purchase or lease of a new plug-in vehicle. There are approximately 200 incentives available to Vermonters, so it pays to act fast!

[Full announcement…]

We can do it: Portugal’s grid runs 4 days straight on only renewables

Climate news is generally dire, but real progress is possible. In fact, it is happening. The latest proof is Portugal’s new record for renewable energy supply: 4 straight days where 100 percent of its power came from renewables.

As renewable energy matures into an ever more popular and cost-effective source of electricity, we’re getting used to seeing some historic achievements from nations that have ramped up their clean energy infrastructure – and the latest glory goes to Portugal.

Recent figures show that the country ran on renewable energy alone for four days straight this month, completing an extraordinary 107-hour run between Saturday morning, May 7, and early Wednesday evening, May 11. During this record-setting window, Portugal ran on solar, wind, and hydro electricity entirely, without needing to fall back on power sourced from its coal and natural gas plants.

Full article.

VNews: “Vt. Nears ‘Net Metering’ Cap With Solar Boom”

Vt. Nears ‘Net Metering’ Cap With Solar Boom

VT Digger commentary: solar vs. “solar”

Solaflect Energy is proud to be a part of helping change our energy economy to one that is based on clean renewables. We do our work because we want a better world, a world with healthier people, a stable climate, more vibrant ecosystems, and an economy that everyone can afford to live in. Solar is our contribution toward those goals. And because we believe in solar, we don’t play games with it. When we tell our customers we are selling them solar energy, we mean it. We don’t do the bait-and-switch that some other companies do.

Vermont Law School professor Kevin Jones has a commentary in VT Digger on this issue.


Editor’s note: This commentary is by Kevin B. Jones, PhD, who is a professor of energy technology and policy at Vermont Law School. He can be contacted at

The sharing economy and solar energy seem like such a natural combination, kind of like apple pie and vanilla ice cream. Green Mountain Power and Yeloha’s recent press release announced that “Yeloha and GMP will make it possible for individuals who don’t have a roof suited for solar to subscribe online to power produced by other homeowners and businesses, essentially going solar on someone else’s roof.”

It almost sounds too good to be true and perhaps it is…

Read the whole commentary at

If you have a shaded roof or for any other reason can’t go solar with panels installed at your home, you can honest-and-truly go solar with hosted, off-site equipment at the Solaflect Community Solar Park.

The best solar homes are efficient solar homes

Energy from the sun is the most abundant and, certainly in the long term, lowest cost way to power our lives and society. But there’s no sense in generating energy only to waste it. Efficiency Vermont is a terrific source of information—and often discounts or rebates—for making your home or business more energy efficient. Their latest email newsletter includes details on improving windows with low-e storms rather than full replacements. Check it out.

low-e windows

Solaflect Community Solar Park outpaces top muni bond fund

According to US News & World Report, the #1 long-term, national municipal bond fund has—over the past ten years—returned an an annual rate of 4.8%. This is the longest time span that US News reports.

Our estimate for the Internal Rate of Return on a Solaflect PV Tracker hosted at our Community Solar Park is 5.0%, over 20 years. The reason we show a comparison with a municipal bond fund is because that sort of investment is non-taxable, and solar net metering provides non-taxable value to residential electricity customers: net metering reduces your cost of living, freeing up your money for other things, but does not provide cash income which would be taxable.

A key assumption in this estimate is that electricity rates with Green Mountain Power will rise at an average annual rate of 2.65%. We use this assumption because that has been the average annual increase in residential electric costs in Vermont over the past 25 years. If rates rise more quickly in the future, then the return on a Tracker increases because it is saving you more than had been assumed.

US News - best long-term national municipal bond fund 2015-09-28b
This screen grab, taken on September 28, 2015, shows US News & World Report’s listing of the #1 long-term, national municipal bond fund. This fund has had an annual return of 4.8% over the past 10 years, less than the expected return from a Tracker at the Community Solar Park. Click on the image to see it shown larger.

Be aware that many solar companies describe the expected Return on Investment (ROI), whereas the estimate above is for the Internal Rate of Return (IRR). These are calculated in different ways and cannot be compared. The IRR is a superior measure of expected performance, because it takes into account the difference between value received in the short term and value received in the long term. Additionally, it gives you a result that can be compared to traditional investment features, such as the interest rate on a CD or money market account. The ROI is much more rudimentary, does not allow for the difference between near term and long term, and cannot be compared to any of those other measurements.

Solaflect helps Norwich to be first 100% solar town in New England

The municipality of Norwich, Vermont is now powered 100% with solar energy provided by Solaflect Energy. Norwich is the first town in New England, and one of only a small number in the United States, to have its town facilities fully powered by solar. Read more about the town’s partnership with Solaflect in this CNBC article.

Solaflect would like to thank Town Manager Neil Fulton, the town Selectboard, and the Norwich Energy Committee for choosing to go solar and for choosing Solaflect to be their partner.