FENECON: Home, commercial and industrial battery storage with its own energy management

Overview

FENECON started in 2011 in Lower Bavaria, where the Feilmeier brothers built their first storage systems in a barn on the family farm, according to the company history. The company counts one of the first series-built commercial storage systems in Europe among its early products, and in 2013 a flood destroyed its warehouse and vehicle fleet. The same period produced the piece of the business that most sets it apart: the FENECON Energy Management System, FEMS, which now ships with every FENECON battery.

FENECON sells complete systems rather than battery modules. A home, commercial or industrial unit arrives with its battery, a matched inverter and a FEMS box that runs charging, self-consumption, tariff and peak-shaving logic on site. FEMS is built on OpenEMS, the open-source energy management platform that FENECON started and released to the community. The OpenEMS repository still credits FENECON GmbH as the originator, while an independent association now governs the project.

The company has grown from a garage operation into one of the larger German storage manufacturers. It opened a factory in Iggensbach in 2024 that electrive reported can build about 500 large storage systems and 30,000 home systems a year, and it moved its headquarters there in March 2025. A second plant in Greenville County, South Carolina, was announced in July 2024 for the US market. The product range runs from 8.4 kWh home systems to industrial containers of more than 4 MWh, all sharing the same energy management software and interfaces.

Offering

FENECON's storage range has three series, each sold with FEMS and a matched inverter.

Home

The Home 6, 10 and 15 are 6, 10 and 15 kW systems from 8.4 to 156.8 kWh of LFP storage, and the Home 20 and 30 are 20 and 30 kW systems from 14 to 168 kWh for larger homes and small businesses. All Home models take over the supply automatically in a power cut.

Commercial

The Commercial 50 and 100 are indoor LFP systems of 50 kW (up to 210 kWh) and 100 kW (39.2 to 420 kWh), with backup power through an optional STS box. The Commercial 92 is a different design: an AC-coupled cluster of KACO blueplanet gridsave 92.0 TL3-S battery inverters and 42 kWh battery towers. Its 2026 product sheet gives 84 kWh and 92 kW for one inverter with two towers, rising to 1,050 kWh and 460 kW with five inverters of five towers each, a 10-year product warranty and a capacity warranty of 12 years or 6,000 cycles. It cannot provide backup power.

Industrial

The Industrial series moves to outdoor NMC systems with active thermal management: Industrial M from 492 to 656 kWh, the Industrial L at 1,288 kWh and 736 kW, and Industrial XL at 4,072 kWh and 1,500 kW. They are aimed at peak shaving, energy market participation, solar and wind parks and energy-intensive plants, and none provides backup power.

FEMS apps

Every system includes the FEMS basic apps for self-consumption optimisation and grid-optimised charging. Extension apps for time-of-use tariffs, peak shaving, SG-Ready heat pumps, heating elements, wallboxes and extra producers and consumers are one-time purchases with no subscription. Systems are quoted through certified installers and wholesale partners, and FENECON publishes no list prices. Its subsidiary FERESTO, founded in 2021, rents storage systems instead of selling them.

Technology

FEMS is the common layer across the range. The Commercial 92 product sheet describes the FEMS box as having four digital inputs, three metered 10 A wet contacts and two dry contacts, and RS-485 Modbus RTU and LAN Modbus TCP to external equipment. Upward it offers a local Modbus/TCP API and REST API and an online cloud REST API, each with read access as standard and write access optional. FEMS runs on OpenEMS, carries the OpenEMS Ready Gold classification, can operate without an internet connection and otherwise talks only to FENECON servers in Germany, according to the Commercial 92 page.

Modbus/TCP read and write access

The FEMS App Modbus/TCP Read Access is installed at the factory. A client on the same network connects to the FEMS IP address on port 502, unit ID 1, with function codes 03 and 04 and zero-based addresses. By default it exposes the _sum component: state of charge at register 302, battery, grid, production and consumption power, and cumulative energy counters. The register table is generated per system and downloaded as an Excel protocol file from Online Monitoring, so the installed configuration, not a generic map, is the reference.

Control is a separate, licensed app. The Modbus/TCP Write Access app is activated with a 16-digit key in the FEMS App Center and adds function codes 06 and 16 on the _sum and ess0 components. An external controller writes active and reactive power setpoints as 32-bit floats from register 706, positive for discharge and negative for charge. A 60-second watchdog stops charging or discharging if no new setpoint arrives, and FEMS clamps each request to what the system can deliver.

OpenEMS

OpenEMS is split into an Edge that runs on site, a Backend that aggregates systems in the cloud and a browser and app UI. The repository licenses Edge and Backend under EPL-2.0 and the UI under AGPL-3.0, and includes drivers for KACO, Refu, Sinexcel, BYD, Pylontech and Soltaro equipment alongside FENECON's own. Because FEMS is built on this code, its component and channel names, such as _sum and ess0, follow OpenEMS conventions.

Markets

Germany is FENECON's home market, and its company page groups its countries into the DACH region (Germany, Austria and Switzerland), the rest of Europe (Cyprus and Greece, the Czech Republic, Italy, Lithuania, the Netherlands and Sweden) and the United States. The home page reports deliveries to more than 20 countries and more than 40,000 systems delivered. Sales go through certified installers and wholesale partners rather than directly to end users.

The three series map onto three customer groups. Home systems serve households with rooftop PV, using backup power and tariff optimisation as the main arguments. Commercial systems serve farms, workshops and businesses that want self-consumption, grid-optimised charging and, on some models, peak shaving. Industrial containers serve energy-intensive plants and solar and wind parks, where the Industrial XL page puts energy market participation and peak shaving at the centre. In March 2025 FENECON reorganised into Home & Commercial, Industrial and Internal Services business units to match, Solarserver reported.

The United States is the main expansion. In July 2024 FENECON announced that it would put its first North American headquarters and manufacturing at 315 Tanner Price Waye in Greenville County, a US$3 million project expected to create 68 jobs, producing and customising the Industrial L, Area Development reported. The US business is led by Thomas Goesswein as chief executive of FENECON International GmbH. BayBG's €5 million investment that month was earmarked for production in Germany and the United States, according to Unternehmeredition.

Company

FENECON GmbH is registered at the Deggendorf local court under HRB 4518. The register extract shows the GmbH formed in November 2016 by converting FENECON GmbH & Co. KG, with FENECON Verwaltungsgesellschaft merged into it, and the business address moving from Deggendorf to Gewerbepark 6, Iggensbach, in March 2025. Franz Josef Feilmeier is the sole managing director, and the share capital has risen in steps to €61,728. The imprint gives the same Iggensbach address.

The company is run by its founding family. Franz-Josef Feilmeier is founder and chief executive; his brother Stefan Feilmeier, formerly chief information officer, became deputy chief executive in 2025, leads FEMS and chairs the OpenEMS Association e.V., which OpenEMS says has about 70 member organisations. The 2025 reorganisation gave the company three business units on three sites: Industrial and the headquarters in Iggensbach, Home & Commercial at a 20,000 m² site in Albersdorf near Vilshofen bought in mid-2024, and central services in Deggendorf, under a ten-member management board.

Outside capital has come from impact and development investors and banks rather than venture funds. The eco-social fund BonVenture invested in 2019, BayBG put in €5 million of growth capital in July 2024, and in March 2025 FENECON closed its first syndicated loan, €40 million arranged by UniCredit with Commerzbank, NORD/LB, DZ Bank and Sparkasse Deggendorf, Solarserver reported. The Iggensbach factory cost about €25 million for its first phase, with €1.7 million of Bavarian and €4.5 million of EU Innovation Fund support, according to electrive.

The key figures FENECON supplied for a GLS Crowd loan offering in August 2025 give 2024 revenue of €136.7 million, net income of €6.0 million, equity of €24.3 million on a balance sheet of €118.6 million (a 21% equity ratio) and 657 MW of storage capacity sold. The company's own site reports more than 400 employees.