Key concepts and practices
What is SOH and why 10 seconds is enough
SOH (State of Health) describes the usable capability of a battery relative to its initial state, usually expressed as capacity retention. It determines range, charging speed, used-car pricing and insurance decisions.
The traditional method is a full charge/discharge capacity test, which takes hours and requires disassembly. The Mottuum MBT series connects to the GB DC fast-charging port, captures the battery response during charging and estimates SOH with a patented algorithm in as fast as 10 seconds, covering 99% of GB DC fast-charging models on the market.
A rapid test is an estimate based on electrochemical response — ideal for screening and trend comparison. When results sit near a threshold, verify with a capacity test before making a warranty or insurance conclusion.
- Compare results at similar temperature and SOC
- Record ambient temperature, SOC, mileage and test time
- For accident vehicles, combine SOH with airtightness and insulation checks
Voltage spread and consistency: when balancing is necessary
A pack consists of many cells in series and parallel; usable capacity is limited by the weakest cell. Over cycles, differences in self-discharge and internal resistance grow, showing up as larger voltage spread, SOC jumps, early charge termination and sudden range loss.
Three signals suggest balancing: a persistently widening static spread, a clear spread at the end of charge, and capacity below similar vehicles. If the spread returns quickly, look for a cell with abnormal self-discharge rather than balancing repeatedly.
The MBEA series charges to a target voltage in CC-CV mode to avoid overshoot; MBCDEA applies higher current during balancing for efficiency. Pack-level consistency work is often combined with the MBCD pack cycler for capacity calibration.
- Record capacity and spread as a baseline first
- Let the pack rest and re-measure after balancing
- Investigate repeat imbalance at cell level
Airtightness: the first physical line of battery safety
If the pack seal fails, moisture and dust enter, insulation drops and connectors corrode; in extreme cases this leads to short circuits and thermal runaway. After collision, underbody impact or reassembly, sealing is the most commonly skipped check.
The MBAT tester handles both packs and cooling circuits: it inflates, stabilises and measures pressure decay to determine leakage, with Pa-level sensor resolution. Results can be linked to the pack ID by QR code for traceability.
For workshops, adding airtightness testing to collision and reassembly workflows reduces comebacks and safety risk; for storage sites, periodic checks directly verify the thermal management system.
- Re-test after any disassembly, collision or underbody repair
- Use separate thresholds for packs and cooling circuits
- Bind test records to the pack ID
When a full pack charge/discharge is needed
Pack cycling solves three problems: capacity calibration, deep maintenance to restore electrochemical state, and verification after module repair.
The MBCD pack cycler reads cell voltages through built-in sensing or CAN, monitors throughout the cycle to avoid overcharge and over-discharge, supports a wide voltage range, and feeds discharge energy back to the grid.
In storage applications, cluster cycling is also used for annual capacity and efficiency verification against contracted availability.
- Check cell voltage distribution and temperature before cycling
- Monitor spread during the cycle and reduce current if abnormal
- Archive cycle data with the test report
Why service records are valuable
Battery service is not only about the repair but about proving what was done and what changed. Complete records are evidence in insurance claims, used-car sales, warranty disputes and storage O&M reviews.
Mottuum equipment supports data storage and one-click export, with QR-linked vehicle or pack IDs, connecting diagnosis, maintenance and verification into one traceable chain.
We recommend a standard template: vehicle information, test parameters, work performed, before/after comparison, technician and timestamp.
