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A Review of the SimpliPhiESS

Solarkobo Score: 4.2/5

Introducing Energy Storage Systems (ESS)

Batteries have been in use for a rather long time both in standalone off-grid setups and in backup power systems. In recent years, however, there has been a significant surge in the popularity of domestic energy storage systems. One of the main drivers behind this trend is the desire for energy security.

Lithium-ion batteries, now recently being offered as 'energy storage systems' or ESS, that is, with advanced features and supporting components that may or may not include a hybrid inverter, MPPT capabilities and a battery management unit, and in 'modular' designs that make them easy to install and used as plug-and-play devices, have grown in popularity over the years. One of the many reasons for this includes the increase in research efforts. For instance, the 2019 Nobel Prize in Physics was awarded for research in Lithium-ion battery technology. Also, the success of the Powerwall and the electric vehicle industry has had a profound effect on the ESS market especially. While lithium-based battery cell technologies are still the costliest of the existing battery technologies, production costs are being driven down by optimal manufacturing processes to meet the boom in demand and more competition that has driven major players in the solar industry into the energy storage segment of the market.

Manufacturer's Profile

The makers of SimpliPhi ESS, SimpliPhi Power Inc. is an American company that was founded in 2010 by Stuart Lennox and Catherine Von Burg with headquarters in California, USA where it manufacturers and ships its products. SimpliPhi originally operated under the name, LibertyPack till 2010 when Stuart Lennox and Catherine Von Burg created the Optimized Energy Storage (OES) product line that is now known as 'SimpliPhi'.

In September 2021, SimpliPhi was acquired by generator company Briggs & Stratton, which was in turn acquired and re-invigorated by private equity firm KPS Capital Partners. A year later, Briggs & Stratton Energy Solutions announced its entrance into the ESS industry with the SimpliPhi ESS. SimpliPhi's founder Stuart Lennox has ties in Hollywood and SimpliPhi's products have been used on the sets of many Hollywood blockbusters.

the simpliphi ess
The SimpliPhi ESS

General Features of the SimpliPhi ESS

LFP Chemistry

The SimpliPhi ESS is made with the Lithium Ferro Phosphate (LFP) cell technology. This means that they do not contain the hazardous element, cobalt that may put users at risk of thermal runaway, fire propagation, operating temperature constraints, and toxic coolants. This makes them safe and long-lasting and also cheaper since cobalt is a rare element that adds significantly to manufacturing costs.

Modular Design

SimpliPhi's batteries are designed to be scaled with the addition of new individual modules. Designed for high voltage installations, 48V, it is rated 4.9 kWh of electricity and up to four individual modules can be wired in parallel and connected to a single SimpliPhi ESS inverter, and up to nine inverters can be wired together. A maximum of 72 batteries can be wired together in this way, holding 352.8 kWh of electricity.

Integrated Design

The SimpliPhi ESS incorporates three core components: a 6 kW SimpliPHI Inverter, a 4.9 kWh Battery and EnergyTrak™ management software. The 6 kW SimpliPHI inverter is integrated with MPPT capability for solar or utility charging and can be DC- or AC-coupled.


The SimpliPhi ESS is maintenance-free meaning that it does not require any maintenance checks during their entire lifespan. Learn all about maintenance-free batteries here.


The SimpliPhi ESS is integrated with an advanced Battery Management System (BMS), with closed-loop communications that logically integrates with the 6 kW Inverter and EnergyTrack management software.

The SimpliPhi ESS Inverter

The SimpliPhi 6 kW inverter is a standard hybrid inverter that can accept up to 7.5 kW of solar input. Also, it can charge batteries up to 100A and 62V. It can be paired with any battery with a battery management system (BMS) that uses the CANBUS communications protocol. Regardless, SimpliPhi insists that it was specifically designed to work with the SimpliPhi ESS, as well as the company’s PHI 3.8 and AmpliPhi 3.8 batteries.

The SimpliPhi inverter offers a notable feature with its automatic generator start capability. In the event of a grid outage, when the inverter detects the battery voltage dropping below a predetermined set-point, it can initiate the startup of a compatible backup generator equipped with a 2-wire start system. This allows the generator to charge the batteries and restore power to the system. Once the batteries reach a specified level of charge, the inverter automatically shuts off the generator until it is required again. With this functionality, the SimpliPhi ESS can operate in off-grid mode using solar panels and a backup generator continuously, providing a reliable and sustainable power solution.

The SimpliPhi ESS Inverter
The EnergyTrack

The SimpliPHI ESS incorporates EnergyTrak, a monitoring and control software platform that allows users to manage their energy usage through a sophisticated mobile app that delivers real-time status and updates to home and business owners. The EnergyTrak mobile app seamlessly and intelligently integrates the inverter and battery at any scale and in any combination for optimum performance.

For Wall Mount Only

The SimpliPhi ESS is built to be mounted on walls and to save usable floor space.

100% Depth of Discharge

SimpliPhi ESS allows up to 100% Depth of Discharge and daily cycling during its lifespan of 10 years. This puts it ahead of some of its competitors like Growatt, Sonnen and AlphaESS.

Wide Temperature Operating Range

The SimpliPhi ESS has a working temperature of -20 to 60 degrees celsius, a capability they share only with the Tesla Powerwall.

IP65 Rating

It has an Ingress Protecting rating of 65. This means it is protected against dust and is able to withstand low-pressure water jets from all directions. In practice, it means that the SimpliPhi ESS can be installed outdoors though an enclosure is recommended.


SimpliPhi is covered by an industry-leading 10-year warranty. It guarantees that the SimpliPhi ESS will maintain 80% of its capacity after the warranty period.

The Boss: SimpliPhi's Carbon-steel Enclosure and Weather-resistant Battery Bank With Both Housing and Wiring Solutions

Other SimpliPhi Batteries

SimpliPhi offers four normal lithium batteries, the Phi 3.8-M, the AmpliPhi 3.8M, the Phi 1.4M and the Phi 730. All of them are made with LFP cells and share other features with the SimpliPhi ESS but they do not incorporate an inverter and are compatible with all industry-standard inverter and charge controllers.

The Phi 730 and Phi 1.4 come in 12V, 24V while the Phi 3.8M come in 24V and 48V configurations. The Ampliphi 3.8 comes only in the 48V configuration. They allow a 100% DoD and are covered by a 10-year performance warranty. They are designed to operate only at the nameplate voltage and are not to be wired in series.

In contrast to many residential lithium battery systems that have fixed capacities or are limited to a small number of modules in parallel, the Phi range offers full scalability. The system can be expanded based on the available capacity of the inverter and solar array, providing flexibility for varying energy storage requirements.

Another key advantage of the Phi batteries is the built-in BMS in each battery module. This advanced system eliminates the need for ventilation, cooling, or thermal regulation, making installation and maintenance simpler and more cost-effective.

The Phi 1.4

The PHI 3.8M
The Phi 730

The SimpliPhi ESS comes very close to the Tesla Powerwall in sophistication. Regardless, it costs almost twice as the Powerwall. In fact, it is by far one of the costliest ESS in the market and on price points, it does not compete well with other Chinese brands manufacturing in territories where labour and materials are cheap. The reason for the higher price point is the additional inverter. SimpliPhi insists on the ESS being compatible only with its inverter. This narrows down the options available to buyers. Regardless, it is highly reputed by industry practitioners for its advanced technology, quality, and longevity and in the case where price is not a major consideration, Solarkobo will confidently recommend it to our clients.

As for its other LFP batteries, they share in the SimpliPhi reputation and have been used in installations in Nigeria. Learn more here. SimpliPhi has a proven track record. Its emphasis is on stability, scalability, and compatibility and for these reasons among many others, we would without any hesitation recommend them to our clients.

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