SubCtech GmbH
Kiel maker of titanium-housed Li-ion PowerPack batteries for AUVs, ROVs and subsea systems, plus OceanPack pCO2 ocean monitoring; part of Gabler since 2025.
SubCtech GmbH is a German maker of lithium-ion batteries for underwater vehicles and subsea installations and of autonomous ocean measurement systems, based at Fraunhoferstrasse 17 in Kiel. The company works in two business units, Ocean Power and Ocean Monitoring, and serves both offshore industry and marine science. Physicist Stefan Marx founded SubCtech as a management buy-out in January 2010. In 2013 it moved into new premises and became an approved vendor to major offshore oil and gas companies under ISO 13628-6 and API 17F, the standards for subsea production systems. The company states that it has more than 70 staff, does its own R&D, and runs series production with selected partner companies rather than outsourcing it.
In August 2025 Gabler Maschinenbau GmbH of Luebeck, part of the Possehl Group and known for hoistable mast systems and other equipment for crewed and uncrewed submarines, acquired SubCtech. SubCtech also joined Gabler Ocean, a group of ocean-technology companies that includes Develogic GmbH in Hamburg and north.io GmbH in Kiel. Both companies kept their own locations. The acquisition announcement named Stefan Marx as continuing managing director. The current imprint lists Gunnar Tons as managing director.
The Ocean Power unit's vehicle batteries are the main link to marine robotics. The PowerPack line is built from SmartPowerBlock modules, each with its own battery-management protection, using industrial 18650 cells in corrosion-free titanium 1-atmosphere housings rather than oil-filled pressure-neutral packs. There are three standard diameters. Series 260 HV uses 2.5 kWh modules and scales from 2.5 to 20 kWh at up to 400 V. Series 310 HV uses 3.5 kWh modules and reaches up to 50 kWh. Series 416 HV uses 7 kWh modules and scales from 7 to 100 kWh at up to 600 V with two 75 A channels. For extra-large vehicles, a Series 416 system of up to 12 batteries can deliver 100 kWh to 1 MWh, with housings rated to 6,000 m. SubCtech lists AUVs, ROVs, submarines, USVs and boats as typical platforms. It offers type qualification to MIL-STD-810G shock and vibration, MIL-STD-461F EMC, API 17F, DNV rules and NATO codes, plus UN T38.3 transport testing. In July 2026 the company reported that a 600 V-class battery and charger with more than 40 kWh, built for a customer-defined underwater platform, delivered 50 kW of continuous power for over 50 minutes at 35 C. This was its first 50 kW AUV battery, up from a previous 35 kW, and its first system in the 600 V class.
For fixed subsea infrastructure, SubCtech supplies subsea UPS units at 24 V and 400 V. The largest 400 V unit holds 18.1 kWh and delivers 5 kW continuous. The company also makes borehole and string batteries rated to 6,900 m, and a Battery Storage Skid energy storage system. Each skid holds twelve 93 kWh modules, for more than 1 MWh, and systems scale to 6 MWh. The skid is designed for 2,000 m water depth and qualified to API 17F, DNV-ST-E273 and UN T38.3. Customised batteries and chargers complete the power range.
The Ocean Monitoring unit builds OceanPack underway ("FerryBox") systems in RACK, CUBE, RACE and AQUA formats, optical pCO2 analyzers with autocalibration to the SOCAT standard, the OceanPack BUOY, subsea frames and landers, PowerLogger and NetDI data loggers, OceanView software, and plankton and microplastic samplers.
Customers shown on the company's client page include Chevron, the Alfred Wegener Institute, GEOMAR, the UK National Oceanography Centre, Dalhousie University, the Kuwait Institute for Scientific Research, the Australian Institute of Marine Science and Sun Yat-sen University. SubCtech holds ISO 9001:2015 certification and states that it works according to ISO 14001. Its staff are trained for IPC-A-600/610 class 3 production. Recognition includes the German-French Business Award in 2013 (shared with SailingOne), a place in Marine Technology Reporter's MTR 100 in 2016, and silver in the Maritime Cluster Northern Germany's MCN Cup in 2021.
Primary type & automation activities this supplier delivers:
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Contact SubCtech GmbH
WEBSITE
https://subctech.com/PHONE
+49 431 22039880HEADQUARTERS
Germany
Company Facts
Founded
2010
Primary Role
Manufacturer
Company Size
-
Primary Region
Europe
Annual Sales
-
Funding Stage
Subsidiary / Acquired
Funding Total
-
Certifications & Memberships
Keywords
- SubCtech GmbH
- PowerPack battery
- SmartPowerBlock
- AUV battery
- ROV battery
- subsea UPS
- subsea energy storage skid
- titanium pressure housing
- OceanPack FerryBox
- pCO2 analyzer
- API 17F
- Manufacturer
- Component Supplier
- Custom Manufacturer
- Power & Energy
- Oil
- Gas & Energy
- Defense & Security
- Education & Research
