Spectro™ Battery Rapid-tester

What is CCA?

CCA is responsible for power delivery

What is Ah (RC)?

Capacity is energy storage, the leading health indicator

Definitions of a Starter Battery

CCA: 30s load at rated CCA at -18C (0F) Battery must stay above 7.2V to pass Ah: Discharge to 10.5V at 0.05C (20h)RC: 25A discharge to 10.5V (in minutes)

Capacity loss

Most battery testers measure CCA only.

CCA stays high while the capacity drops. This makes impedance testers ineffective.

Capacity is the leading health indicator, but this value is difficult to estimate.

Many battery testers claim to measure capacity. This is not possible with a basic impedance measurement.

Testing Starter Batteries

CCA value relates to internal resistance

Capacity and CCA of aging Starter Batteries

CCA stays high to the end; engine cranks well Capacity below 40% is considered end-of-life

Relationship between Capacity and CCA

175 starter batteries tested according to SAE J537

Few touch the 50% CCA line

Most batteries hug the 40% capacity line

Capacity determines the end-of-battery life. CCA not conclusive

Spectro CA-12

Measures Capacity of Lead Acid

Device scans battery with 20-2000Hz

Uses multi-model electrochemical impedance spectroscopy (Spectro™)

Estimates capacity in 15 seconds

Provides higher CCA accuracy than with single-frequency AC methods

15-second test

No comparable product on marketUS patent 6,778,913

Spectro is based on Frequency Domain using electrochemical impedance spectroscopy (EIS).

A frequency scan creates a Nyquist plot.

Nyquist plot

How does Spectro™ work?

Randle’s Electrochemical Model

Cadex took EIS and developed multi-model electro-chemical impedance spectroscopy, or Spectro™

Spectro™ combines EIS with complex modeling to estimate battery capacity and improve CCA results

Taking EIS Further

“All models are wrong, but some are useful”

George Box, 1919-2013

Spectro™ Progression

Signal control anddata acquisition

Filtering, phase andmagnitude extraction

Modeling, statistical analysisFitting Nyquist plots of electrochemical models to the measured Nyquist plot

Data fusionCorrelating values of key parameters to derive at capacity, CCA estimations

1

2

3

4

V= Vocos(2pft)I= Iocos(2pft + q)V= Vocos(2pft)

Generating Nyquist PlotIm

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Real Impedance

Spectro™ scans the battery with 22 frequencies, generates Nyquist Plot and fits electrochemical models

Fitting Electrochemical Models

Electrochemical models evaluate R1, R2 and C of the Randle Model.

C decreases, R2 increases and the Nyquist radius flattens with age.

Randle Model

Real Impedance

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Test conditions

Battery must be at least 60% charged. “Charge and Retest” message if below 60%

Specific Matrix gives capacity in % (accuracy +/-15%)

Generic Solution passes or fails battery on a 40% capacity threshold (accuracy +/-20%)

Accuracy is based on symptoms

Low charge and faded capacity appear similar

Low formation, long storage, surface charge falsify results

What is a Matrix?

A matrix can be compared to letter or facial recognition. Samples are needed against which results are compared.

A matrix is developed by scanning many good, marginal and poor batteries.

Most service personnel use the generic matrix.

The pass/fail provides conclusive test results.

Battery-specific matrix reads the capacity in %

Generic Matrix gives a pass/fail a 40% threshold

CCA test with CA-12: 97%

CCA test with competitor: 51%

 

According to independent

test lab 

 

13%

87%

Correct Incorrect

Capacity test with CA-12: 87%

Capacity test with competitor: N/A

97%

3%

Correct Incorrect

Correct prediction with Specific Matrix

CCA Capacity

AGM 70-90 Ahr

Correct prediction with Generic MatrixCapacity only

Flooded 70-90 Ahr

Batteries were charged and discharged according to EN-Norms. Results were compared with Spectro CA-12

CCA accuracy +/-5%;Capacity accuracy +/-20%

General service garages Warranty at dealership Fleet vehicles

Markets for Car and Truck Dealerships

Battery health in boats, aircraft and heavy equipment are best verified with a capacity check.

Markets for off-road Vehicles

Capacity is the leading indicator when to replace a battery. Capacity also governs the hotel load.

Markets for diverse Vehicles

Markets for Deep-cycle and UPS Batteries

Spectro CA-12 estimates capacity without discharge. Enables more frequent battery check.

Limitations: - Provides SoC only- Cannot estimate capacity- Loses accuracy as battery ages

Sensor reads voltage, current, temperature

Battery Monitoring - what is used today

Adding capacity to BMS ─ On Drawing Board ─

Adding capacity advances a battery sensor to an advanced BMS providing State-of-Function (SoF)

SoF in a Tri-state Fuel Gauge

Tri-state Fuel Gauge shows Usable capacity Empty portion Unusable capacity

Conceptual

─ On Drawing Board ─

Markets