Briggs & Stratton Energy Solutions Introduces More Powerful, More Affordable Home Battery System

SimpliPHI® 6.6 Powers Homes Through Power Outages, Creates Energy Resilience

MILWAUKEE, WI (March 04, 2024) – For homeowners looking for reliable, quiet, emission-free backup energy, Briggs & Stratton Energy Solutions is introducing its SimpliPHI® 6.6 Home Battery System. This innovative new battery is more powerful, more affordable, more versatile and more compact than other systems. The SimpliPHI 6.6 uses advanced lithium ferro phosphate (LFP) chemistry and can provide enough power to get a home through a “typical” outage. 

Briggs & Stratton’s new SimpliPHI 6.6 battery delivers 6.65 kWh of energy and can be installed in stacks of one to three. For increased power, a system can be scaled to six stacks of three with the 18 batteries delivering 119.7 kWh with maximum continuous power of 84 kW.

With the average power outage in the U.S. lasting 5.5 hours1, a one-battery SimpliPHI 6.6 system can meet the needs of many homeowners by delivering more than 10 hours of power at 50% backup load*. The SimpliPHI battery system can be used as an alternative to a standby generator, offering additional installation flexibility and versatility.

In addition to providing backup power during a utility outage, the SimpliPHI 6.6 battery system can be used during peak utility rate times or with demand response programs to lower utility bills. The system can supplement solar energy or be paired with a generator for off-grid power.

“We’re breaking new ground with the SimpliPHI 6.6 battery and are continuing to innovate and help homeowners achieve energy resilience and independence,” said Tom Rugg, SVP & President - Briggs & Stratton Energy Solutions. “We’re also focused on affordability. The SimpliPHI 6.6 battery is 25% less expensive than our competitors, and that is before tax incentives.”

The SimpliPHI 6.6 battery stack is extremely versatile and gives homeowners multiple  installation options. It is outdoor rated so it can be installed indoors or outdoors with no additional cabinets required. The system can be ground- or wall-mounted inside a garage, shed or basement or outside on an exterior wall. The flexibility of using one, two or three batteries per stack means the system can fit into small spaces.  

Aesthetically, the SimpliPHI 6.6 features a sleek design and is more compact and lighter than other systems. Each battery is 17.3” tall by 28.6” wide by 6.7” deep. 

On the technology front, the SimpliPHI 6.6 uses LFP chemistry that’s been proven to be safer and less prone to thermal runaway. In fact, SimpliPHI batteries have been used around the world for more than a decade in some of the harshest environments. In 2010, the U.S. Department of Defense used SimpliPHI batteries to deliver mission-critical power on Forward Operating Bases in Iraq and Afghanistan. 

The LFP chemistry allows for 6,000+ cycles @ 80% DoD with an end-of-life capacity of 75%. An increased discharge rate of .7C to 1C delivers more storage capacity per hour. In addition, an expanded temperature range allows for full operating/discharging rate from -20 ºC to 55 ºC and full charging rate from -10 ºC to 50 ºC. 

Tested and certified to the most stringent standards, the SimpliPHI 6.6 battery is UL 1642, UL 1973, UN 3480 and UN DOT 38.3 certified and has gone through UL 9540A fire safety testing. It recently secured its UL 9540 Edition 3 certification as a standalone DC ESS. 

The SimpliPHI 6.6 battery is compatible with the SimpliPHIⓇ 6kW hybrid inverter, Sol-Ark® 8K, 12K and 15K inverters, as well as other leading lithium supporting inverters. 


Configurations & Cost

Briggs & Stratton offers ESS Packages that make choosing a system easy.

The complete, one-battery Essential Backup Package, which includes a single SimpliPHI 6.6 battery, a battery controller, ground or wall base, SimpliPHI 6kW hybrid inverter and gateway, has an MSRP of approximately $10,800 with installation and comes with a 10-year limited warranty. When the 30% federal Inflation Reduction Act tax credit is applied, the cost drops to approximately $7,560 with installation.

The two-battery Managed Loads Package allows consumers to add additional appliances and delivers more than 14 hours of power at 75% backup load*. The complete two-battery 6.6 SimpliPHI system with a Sol-Ark® 12K inverter and installation is approximately $15,400 and $10,800 with the tax credit. 

The three-battery Whole House Package allows a typical homeowner to power nearly everything in their home and delivers more than 16 hours of power at 100% backup load*. The complete three-battery system with a Sol-ArkⓇ 15K inverter and installation is approximately $19,000 or $13,300 with the tax credit.

Additional batteries can be added to each package to provide more power for larger appliances and equipment, like an air conditioning unit.

The SimpliPHI 6.6 battery and 6 kW inverter have a 10-year limited warranty, and the 6.6 battery is guaranteed to retain 75% capacity after 10 years 2 Plus, SimpliPHI Batteries are backed by Briggs & Stratton’s 115 years of experience in power solutions.


How It Works

Each SimpliPHI 6.6 battery system starts with a ground or wall base. The batteries are placed one by one on top of each other and click into place with RapidStak™ technology. Each battery stack is topped with a battery controller. The controller has a series of four lights that indicate the amount of power available from 25% to 100%. Each battery has an individual green light that illuminates when it’s powered. 

Once the battery installation and commissioning are complete, homeowners can monitor and manage their Briggs & Stratton SimpliPHI 6.6 battery system through the EnergyTrak™ mobile app. All EnergyTrak data is securely stored in the United States.

Briggs & Stratton Energy Solutions is currently taking pre-orders for its SimpliPHI 6.6 battery system.  

In addition to its energy storage systems, Briggs & Stratton Energy Solutions offers a full line of industry leading home standby generators. For more information, visit

Media Contact

Monica Baer
(414) 881-5053

About Briggs & Stratton

Briggs & Stratton, headquartered in Milwaukee, Wisconsin, provides innovative products and diverse power solutions to help people get work done. Briggs & Stratton is the world’s largest producer of engines for outdoor power equipment and is a leading designer, manufacturer and marketer of lithium-ion batteries, standby generators, energy storage systems, lawn and garden, turf care and job site products through its Briggs & Stratton®, Vanguard®, Ferris®, Simplicity®, Snapper®, Billy Goat®, Allmand®, Branco® and Victa® brands. Briggs & Stratton products are designed, manufactured, marketed and serviced in more than 100 countries on six continents.

2 See operator’s manual or for complete warranty details. Designed and engineered in California, USA. Briggs & Stratton has a policy of continuous product improvement and reserves the right to modify its specifications at any time and without prior notice Please visit for the latest information.

* Backup loads where the average continuous load is 1.23kW.