SubCtech has completed full-load electrical testing for a customer-defined underwater platform, successfully demonstrating 50 kW of continuous power from a 600 V-class autonomous underwater vehicle (AUV) battery system.
The test validated a power system designed for high discharge rates, featuring a nominal voltage of approximately 600 V and a nominal energy capacity exceeding 40 kWh. Operating at an ambient test temperature of 35 °C, the battery sustained a constant load of 50 kW for more than 50 minutes. This output surpassed the customer’s minimum 45-minute runtime requirement by more than 11 percent, maintaining full power throughout the duration without encountering thermal throttling or temperature-related output limits.
The demonstration marks SubCtech’s formal entry into the 600 V-class battery market and represents a scaling up from its previous continuous power benchmark of 35 kW. Rather than adopting unproven core technologies, the engineering team achieved the performance increase by optimizing and expanding the company’s existing technology platform.
“For the first time, we have demonstrated the truly enormous performance of 50 kW continuous power from an AUV battery system. And we achieved this based on our proven technology, without having to introduce fundamentally new technologies,” says Stefan Marx, CEO. “The test even ran for more than 50 minutes instead of the required 45 minutes. Under these conditions, this is an outstanding result and a major achievement for the entire team.”
Sustaining unthrottled load under continuous full power addresses core challenges in subsea engineering, where energy density, high discharge capability, thermal management, and structural reliability must be balanced inside tightly constrained hull volumes. Leveraging an established platform provides technological maturity for subsea operators requiring predictable performance in harsh environments.
“But with the best team – and by that I mean everyone at SubCtech – we had absolute confidence that we could deliver. This result once again confirms our position as a leading global supplier of high-performance underwater battery systems,” says Stefan Marx.
Following the full-load testing milestone, the program will advance to Factory Acceptance Testing (FAT) at SubCtech’s facilities before progressing to customer-side Onsite Acceptance Testing (OSAT) in autumn. The system will also undergo qualification against MIL-STD-810G and MIL-STD-461E/F standards, evaluating environmental robustness, shock and vibration resilience, temperature and humidity tolerance, and electromagnetic compatibility.
