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Batteries from Jauch for ultra-high-precision SRM products
For many years, Jauch Batteries have been designed into both the SRM bike computer (Head Unit) and the SRM Spider PowerMeter. The power supply is an integral part of these highly advanced systems and has been consistently maintained across multiple product generations. Both power measurement directly in the drivetrain and the display and processing of performance data in the bike computer rely on reliable Jauch Battery solutions that are optimized for each specific application.
SRM – Specialist in precise power measurement for cycling
Schoberer Rad Meßtechnik GmbH (SRM), headquartered in Jülich, North Rhine–Westphalia, is one of the technological pioneers in cycling. In the 1980s, the company developed the world’s first bicycle power meter and has shaped objective performance measurement in professional and elite sports for decades.
Even after additional suppliers entered the market, SRM PowerMeters are still regarded as exceptionally accurate and reliable. Top athletes such as triathletes Laura Philipp and Patrick Lange, both Ironman World Champions, as well as outstanding mountain biker Pauline Ferrand-Prévot, use or have used SRM PowerMeters in training and competition. The focus is on outstanding measurement accuracy, which ensures reliable comparability in competition while also enabling precise, long-term monitoring of training development.
What does a PowerMeter measure?
A bicycle power meter measures the mechanical power that a rider applies to the drivetrain. This power is expressed in watts and enables objective training control, independent of external factors such as wind, terrain, or temperature.
From a technical perspective, the measurement is based on strain gauges that detect minimal material deformation caused by the applied force. In addition, various sensors measure angular velocity (also known as cadence) and the angular position of the crank. By combining force and speed data, the system calculates the mechanical power output in watts. The angular position data also makes it possible to determine how power distribution differs between the right and left leg. All measured data is then transmitted wirelessly to training systems.
The Spider PowerMeter – Power Measurement at the Heart of the Drivetrain
In the SRM Spider PowerMeter, power measurement takes place in the spider, the connecting element between the crank arms and the chainrings. The crank is a central component of the drivetrain, as all forces generated by the rider must pass through this area.
By integrating the power meter into the spider, power is measured directly within the force path. The electronics and power supply are safely housed inside the crank, enabling long-term stable and reliable measurement.
Use in performance-oriented cycling
SRM Spider PowerMeters are used across various cycling disciplines:
- Road cycling: long periods of sustained effort and consistent power output
- Mountain biking: exposure to dirt, moisture, and mechanical shock
- Track & indoor cycling: high cadences and steady power delivery
Regardless of the operating environment, the power supply must function reliably, as it plays a crucial role in ensuring measurement stability.
Requirements for the Power Supply
The technical design of the Spider PowerMeter places high demands on the Battery:
- Extremely limited installation space within the crank
- Mechanical stress caused by vibrations and shocks
- Exposure to temperature fluctuations and moisture
- Long-term reliability over many charge cycles
Jauch Battery Solution in the SRM Spider PowerMeter
For many years, SRM has relied on Batteries from Jauch. Earlier generations of the PowerMeter were equipped with non‑rechargeable primary cells. The current SRM Spider PowerMeter 9 uses two rechargeable Lithium Polymer Pouch Cells with an integrated Protection Circuit Module (PCM).
The flat pouch design allows space‑efficient integration within the Spider’s highly restricted installation space. An integrated PCM reliably protects the battery against overcharging, deep discharge, and overcurrent, ensuring safe and stable operation over many charge cycles. Depending on the usage profile, operating times of more than 100 hours are achievable.
The cell solution is certified in accordance with UN 38.3 and therefore meets international requirements for the safe transport of Lithium Batteries. This certification ensures safe and reliable battery performance even under transport conditions such as pressure, temperature fluctuations, or vibration stress.
Long-standing collaboration
The long-standing partnership between SRM and Jauch is based on close technical coordination and experience gained across multiple product generations, in which the power supply plays a central role as a safety‑ and function‑critical component.
“The quality of Jauch Batteries has been consistently high for many years and is absolutely reliable for our PowerMeters,” says Michael Scholz, Media & Marketing at SRM / Stefan van Kempen, Production Manager at SRM.
The SRM Bike Computer (Head Unit) – Display and Analysis of Performance Data
In addition to PowerMeters, SRM also develops bike computers (Head Units) that serve as the central interface between the rider and the measurement system. They receive and visualize performance data such as power output, cadence, and training parameters. Here as well, integrated Jauch Battery solutions are used. The current PowerControl 8 (PC8) model features a rechargeable Jauch Lithium Polymer Battery. The bike computer is now entering the next development phase, with a new generation taking shape. Which Jauch Battery solution will be used will be presented in a dedicated customer success story.
Conclusion
Precise power measurement in cycling starts with a stable power supply. For more than two decades, Jauch Batteries have made a significant contribution to the reliability and measurement accuracy of SRM Spider PowerMeters as well as bike computers (Head Units).
They therefore form a key technical foundation for a system that has become firmly established worldwide in performance‑oriented cycling.
Jan Wein, Sales Manager
+49 7720 945 162
