Briggs & Stratton’s new lineup of Battery Backup Packages feature the company’s SimpliPHI 6.6 stackable batteries paired with EG4 Inverters, providing an easy way for installers to meet customers’ power needs with Essential Power, Managed Power and Whole Home Power options.

MILWAUKEE, WI (September 9, 2025) - Briggs & Stratton and EG4 have established a new working relationship. Briggs & StrattonⓇ SimpliPHIⓇ 6.6 batteries and PowerProtectTM standby generators now integrate with EG4 inverters.

"This partnership brings together two strong entities. EG4 is a recognized leader in the inverter market and Briggs & Stratton has been a leader in power solutions across a diverse set of markets for more than 117 years," said Tom Rugg, SVP & President - Briggs & Stratton Energy Solutions. "This strategic partnership allows us to continue to offer more options for installers, including hybrid energy solutions with both batteries and generators."

Briggs & Stratton's new lineup of Battery Backup Packages feature the company's SimpliPHI 6.6 stackable batteries paired with EG4 Inverters, providing an easy way for installers to meet customers' power needs with Essential Power, Managed Power and Whole Home Power options.

The Briggs & Stratton battery packages seamlessly integrate with EG4's 12KPV and 18KPV all-in-one hybrid inverters. Briggs & Stratton batteries and generators also integrate with FlexBOSS18 and FlexBOSS21 hybrid inverters and the GridBOSS microgrid interconnect device (MID), which pairs with the FlexBOSS line of inverters. The full closed-loop integration for advanced communication with all EG4 inverters makes commissioning and operation smoother and more efficient.


Photo caption: Briggs & StrattonⓇ SimpliPHIⓇ 6.6 batteries now integrate with EG4 inverters.

The EG4 inverters offer flexible installation options and enhanced power output, making them an accessible entry point into hybrid solar without compromising on performance. The EG4 FlexBOSS21, FlexBOSS18 and 18KPV inverters are also EMP-hardened, ensuring reliable performance during Electromagnetic Pulse (EMP) events.

In addition, EG4 inverters now integrate with Briggs & Stratton's PowerProtect home standby generators.
"Our collaboration with Briggs & Stratton combines EG4's advanced energy storage systems with their proven generator and storage technologies to give customers more ways to achieve reliable, uninterrupted power," said James Showalter, founder and CEO of EG4. "Whether pairing EG4 ESS with Briggs & Stratton generators for seamless backup or utilizing the new compatibility between the SimpliPHI 6.6 battery system and EG4 inverters, with this partnership we are making it easier than ever to build the right solution for energy independence."

SimpliPHI 6.6 Package Details
Briggs & Stratton SimpliPHI battery backup packages start with one, two or three SimpliPHI 6.6 batteries that deliver a range of power. The package concept centers on how much of the home the user wants to power during an outage - from 50% of a home's normal energy usage to 100%, which allows the homeowner to power everything in their home for a period of time. While the packages recommend a starting number of batteries, they are scalable. To add more backup time, simply add more batteries. Systems can be scaled as the customer's energy needs change.

The continuous energy use of an average U.S. home is 1.23kW. Given a home's average energy use, a one-battery system with an EG4 12PV inverter delivers 10.8 hours at 50% backup load. A two-battery system with an EG4 18PV inverter delivers 14.5 hours at 75% backup load and a three-battery system with an EG4 18PV inverter delivers 16.4 hours at 100% backup load. All with a 200A pass-thru for easy integration into most homes' main service panel. For larger installations, the battery system can be scaled up to 18 batteries, delivering 119.7 kWh with maximum continuous power of 84 kW or 90 hours of power at 100% load. Utilizing the FlexBoss/GridBoss combinations, installers can continue to scale power at a lower cost, have a simplified wiring configuration and further maximize power output.

"We are excited to expand our closed-loop integrations with EG4. We have been consistently impressed with their approach to the market, innovative design choices and products that reliably serve their customers," said Sequoya Cross, vice president of energy storage for Briggs & Stratton Energy Solutions.

Quicker Battery Installation
Briggs & Stratton SimpliPHI 6.6 batteries feature a number of advances that make installation easier. They have self-guiding RapidStak™ connectors that integrate power and communications into a single point without wires or DIP switches. The batteries simply stack on top of one another and click into place, making installation easier and more efficient. Assembling a stack of three can be done in five minutes or less.

They are IP65 rated so they can be installed indoors or outdoors with no additional cabinets required. They can be ground- or wall-mounted inside a garage, shed, utility closet or basement or outside on an exterior wall. Plus, the flexibility of using one, two or three batteries per stack means the system can fit into compact spaces.

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. In 2024, it secured its UL 9540 Edition 3 certification as a standalone DC ESS and recently passed the earthquake vibration test (GR-63-CORE, Issue 5. Section 4.4.1) conducted by Element U.S. Space & Defense.

The SimpliPHI 6.6 battery has a 15-year limited warranty and is guaranteed to retain 60% capacity after 15 years.1 Plus, SimpliPHI batteries are backed by Briggs & Stratton's 117 years of experience in power solutions.

For more information on products from Briggs & Stratton Energy Solutions, visit energy.briggsandstratton.com.
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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.

1 See operator's manual or energy.briggsandstratton.com for complete warranty details. 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 energy.briggsandstratton.com for the latest information.