Electrical measurement technology company LEM has introduced a new single monitoring unit (SMU) sensor range to provide accurate state of charge (SOC) estimation for electric and hybrid vehicle technologies.

The SMU continuously monitors such vehicle parameters as battery performance and safety systems. The sensor identifies anomalies and supports diagnostics, to help improve vehicle efficiency and ensure compliance with regulations.

The compact unit measures 29.1mm x 35.5 mm x 49.9 mm and the busbar thickness is 2 mm to 3 mm compatible to improve accuracy and accommodate a range of different busbar dimensions.

The SMU uses the latest LEM9 application-specific integrated circuit (ASIC) to measure environmental factors while ensuring accurate sensor performance at the Battery Disconnect Unit (BDU) level. It has built-in software algorithms that can correct or adjust measurement data to account for distortions or errors caused by mechanical stresses, making it possible to reach 1% of accuracy up to 1300 A and <1.7% up to 1500 A, according to the company.

Other features include digital calibration, which provides end-to-end (E2E) protection, improved offset/sensitivity calibration, and diagnostic warnings such as under-voltage or overvoltage.

A dedicated safe state mode avoids malfunction if issues such as sensitivity and offset drift, temperature measurement errors, or memory errors are detected. The sensor’s internal microcontroller includes a built-in algorithm to correct for magnetic offset, ensuring more accurate and reliable sensor readings by eliminating errors caused by residual magnetism. The sensor’s high isolation levels enable it to withstand voltage differences greater than 800 V between components or between the device and its surroundings, preventing electrical interference or damage.

The new SMU family is compliant with the Automotive Safety Integrity Level (ASIL) requirements built into the ISO 26262 standard for functional safety in vehicles.

Source: LEM