BU-919: Building a Matrix to test Batteries

Multi-Model EIS is a new battery test technology that departs from traditional load-testing by modeling a battery against a matrix to assess capacity, CCA, state-of-charge and other characteristics. Known as Spectro™, the non-invasive* innovation services lead acid and Li-ion in about 30 seconds.

To expand test range to 48V (nominal) and capacities of 300Ah, Spectro™ uses EIS Direct Drive that imposes the scanning frequencies which produces a ripple voltage without the need of decoupling capacitor. This reduces circuit size and avoids cooling. A typical frequency scan is from 2,000Hz to 4Hz; lower for very large batteries. Minimal battery test resistance is 300µΩ.

Test accuracies rest on Matrix Integrity Level (MIL) that is achieved by scanning batteries with different performances of the same model. An analogy is a bridge is a bridge that is suspended by pillars, each representing batteries with unique capacity fade. Spectro presents thee matrix types:

Generic Matrix: Gives capacity and CCA pass/fail on starter batteries
Custom Matrix serves a select group of batteries with improved MIL
Model-specific are matrices made for a battery with goal for numeric readout

Starter batteries use the generic matrix with pass/fail classification. A pass gives a grace period to next service, fail calls for replacement even if cranking is still strong. The Spectro device reads capacity, the leading health indicator of a battery. Post-mortem studies reveal that capacity fade is the failure cause of 48 in 100 batteries. Low CCA only represents 12 in 100.

Custom matrices for specialty batteries can be created by testing retired batteries with the Data Acquisition Unit (DAU). The DAU is a portable lab we send to interested parties to scan retired batteries as they become available from time to time. The pool of batteries forming a new matrix also requires scanning new and slightly used batteries to satisfy the full capacity distribution.

Each custom matrix requires at least 12 batteries of diverse capacity, distributed similar to the pillars of a bridge. The more batteries being scanned within a given performance level, the more articulate the readings become. Our goal is to advance MIL to give numeric capacity readings, but the extent of accuracy is governed by the user and the availability of batteries.

The matrices are stored in the Matrix Library that is accessible by Cloud Analytics to form an open battery test system. Using custom matrices to test performance of unique batteries opens a new level of battery analysis we call Deep Battery Diagnostics. Service technician know that voltage and load tests are unable to read battery capacity. Testing by batteries with Multi-Model EIS delivers the Remaining Useful Life (RUL) of a battery by revealing the Minimum Operational Reserve Energy (MORE). Cloud Analytics tracks batteries from workforce to retirement.

* EIS Direct Drive is slightly invasive

Last Updated: 3-Dec-2025

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Batteries In A Portable World

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