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Multi-Model EIS

EIS Direct Drive

See inside the battery without taking it out of service.

Multi-Model Electrochemical Impedance Spectroscopy (EIS) reads a battery’s electrochemical response and compares it with proven models to classify capacity and assess state of charge, power capability, and anomalies.

The result is a fast, non-invasive view of battery condition that helps teams act before weak batteries interrupt operations.

EIS Direct Drive excitation signal A small excitation signal is applied across the battery voltage over time without a discharge test. Battery Voltage Excitation EIS Direct Drive Noninvasive battery analysis Time

30 sec

Typical test time

3–48 V

Spectro Modular range

Up to 300 Ah

Supported capacity

≥300 µΩ

Battery resistance

How it works

From electrochemical signal to a service decision

Instead of relying on a heavy discharge test, Multi-Model EIS analyzes the battery’s response across frequencies and finds the closest match in a library of battery models.

01

Excitation

Spectro™ applies controlled sine-wave signals and records the battery’s electrochemical response.

02

Modeling

The resulting Nyquist signature is compared against matrices built from batteries at known health conditions.

03

Decision

The models translate complex evidence into capacity, state of charge, power capability, and anomaly insights.

Battery condition, made visible

One test reveals more than a voltage or cranking check.

A battery can look identical when it is full, empty, or near end of life. Multi-Model EIS adds the condition data needed to distinguish between them.

State of energy

Capacity indicates remaining useful runtime.

State of power

Resistance helps validate the ability to deliver power.

State of charge

Available charge supports mission and shift readiness.

State of safety

Electrochemical anomalies can flag batteries for closer review.

Capacity and cranking performance over battery life Capacity crosses the service threshold while cold cranking ability remains comparatively strong. Cranking performance Capacity Service threshold New Aged

The leading health indicator

Power can look strong while capacity fades.

A cranking or resistance check shows whether a battery can deliver power now. Capacity shows how long it can continue doing useful work.

By classifying capacity alongside state of charge and resistance, Multi-Model EIS helps establish Minimum Operational Reserve Energy (MORE). This is the point where reliability, service timing, and battery economics meet.

Minimum Operational Reserve Energy

Set the reserve your operation needs.

Minimum Operational Reserve Energy (MORE) defines the lowest acceptable battery capacity for a specific application. It creates a practical service threshold between using a battery fully and replacing it before reliability is at risk.

Multi-Model EIS classifies capacity without a full discharge, allowing Spectro™ to compare each result with the selected MORE target and return a clear service decision.

01

Set

Choose the reserve-energy target for the application.

02

Assess

Classify capacity non-invasively.

03

Act

Keep, service, or replace before failure.

Minimum Operational Reserve Energy battery graphic A vertical battery shows CCA to 30 percent, hotel load to 50 percent, energy reserve above 50 percent, and capacity fade at the top. The MORE indicator reaches the 50 percent target. Battery reserve at end of shift Capacity fade Energy Reserve Hotel Load CCA 100% 50% 30% 0% MORE Capacity fade Unavailable capacity Energy Reserve Capacity above hotel load Hotel Load 30–50% operating load CCA 0–30% starting reserve MORE helps prevent critical depletion before the next shift.

40%

Starter batteries

50%

Heavy-duty vehicles

60%

Mobility and standby

Example targets shown. The appropriate MORE setting depends on the application.

Where it fits

One technology, multiple battery decisions

Use Multi-Model EIS in the field, in quality control, or as part of a connected battery-management system.

Fleet and field service

Assess starter, deep-cycle, and standby batteries without a full discharge. Find weak units, compare batteries in a string, and plan replacement before failure.

Explore Spectro™ Modular

Manufacturing and quality

Overlay Nyquist signatures, define acceptance fields, compare production batches, inspect incoming batteries, and support warranty analysis.

Explore Spectro™ Explorer

BMS, UPS, and energy storage

Integrate compact EIS measurement into a battery-management system to add capacity estimation and electrochemical anomaly detection.

Discuss OEM integration

Put the evidence to work

Choose the right Multi-Model EIS path for your batteries.

Start with a field-ready Spectro instrument, develop a battery matrix, or discuss embedding the technology into your BMS.