Taiwan's first independent EV battery certification. Booking is open.
CELLPROOF芯況

Taiwan's first independent EV battery certification

Before you buy a used EV,see the battery's real health.

Measured by an independent third party. Not the dashboard number. Not the seller's own readout.

Book a testVerify
Sample
cellproof.com.tw/r/…

DEEP full test · measured

SampleCELLPROOF芯況

2021 Tesla Model 3 RWD

LFP 60 kWh · 108 cell groups

VIN
*********LFABC123
Mileage
48,200 km
Test date
2026/09/18
Certificate ID
SAMPLE2345

Check the last 8 characters of the VIN and the mileage against the car

Battery health

94.0%Good condition

DEEP full test

Charged to 100%, with the energy going in measured

Car's own figure vs measured

+4.4%Normal

Reported by the car
58.9 kWh
Measured by Cellproof
56.4 kWh

Checks

Tap an item to see the number
  • Battery management systemNormal
  • Cell balanceNormal

    12 mV

  • Temperature spreadNormal

    3.1 °C

  • High-voltage insulationNormal

    4.8 MΩ

  • SensorsNormal
  • Fault codesNormal

    0

  • 12V batteryNormal

    12.6 V

  • Fast-charge useNormal

    18.5%

Original battery warranty

8 years or 160,000 km, whichever comes first

Time2.9 years left

Distance111,800 km left

Estimated from the manufacturer's published terms. The manufacturer's own record decides the actual warranty.

Conclusion

Good condition · No faults found

Measured by charging, this car's usable battery energy is 94.0% of the factory figure. That reads as "Good condition". Every check is normal. The car's own figure is within the normal range of the measured one.

Compared with the same model

Still collecting data (0 cars so far)

The spread appears here once enough cars with the same model and battery have had a DEEP test. We do not draw a curve without data.

Energy
NominalUsable
Now60.9 kWh56.4 kWh
When new64.5 kWh60.0 kWh
Range estimate
Official testTypical useThis car
Now376 km310 km298 km
When new400 km330 km

Estimates. Real range depends on driving style, temperature and road.

Cell voltage map
108 cell groups, coloured by distance from the median
Min
3.400 V
Average
3.406 V
Max
3.412 V
Charge curve
050100060120180240300360420min
Charge %Current AVoltage VRestSensor zero -0.309 A
Measurement record
Method
AC charging, to 100%
Starting charge
14.0% (after resting 2.5 h)
Final charge
100.0% (after resting 2.0 h)
Charging time
6 h 55 min
Ambient temperature
about 28°C
Energy charged
48.5 kWh
Current sensor zero
-0.309 A (subtracted)
Against the factory battery test
Tesla battery health test
93.2%
Cellproof DEEP
94.0%
Difference
+0.8%

Both recorded on the same charge cycle

Readings
Battery temperature · Min / Max
28.1 / 31.2 °C
Battery temperature · Spread
3.1 °C
Cell voltage · Min / Max
3.400 / 3.412 V
Cell voltage · Spread
12 mV
Pack voltage
383.4 V
Values reported by the car
BMS charge (SoC)*
100%
BMS health (SoH)*
98%
BMS reported capacity*
58.9 kWh

* These values come from the car's battery management system. Cellproof did not calculate them.

Usage history
Total energy charged
38,400 kWh
Equivalent full cycles
about 640
DC fast-charge share
18.5%
Test log
  1. 09:10接上診斷接口，開始記錄
  2. 11:40靜置結束，起始電量 14.0%
  3. 18:35充電至 100%，停止充電
  4. 20:35靜置結束，結束記錄
Method and limits
Health is defined as
Measured usable energy ÷ factory usable energy (the SOCE definition in UN GTR 22)
Conditions
AC slow charging
Data source
Raw voltage and current signals from the car's CAN bus
Accuracy
Not yet published (comparison data still being collected: 0 cars)
Tester
林承翰（範例）

The full test method

This certificate reflects the state of the battery on the test date. It is not a guarantee of battery life, range or warranty. Measurements use the car's own sensors, corrected for zero offset.This test does not assess mechanical damage or outside factors.

Independence Pledge. We take no part in any vehicle sale, and we take no referral fees, kickbacks or sales commission from dealers. A result does not change because the client is a buyer, a seller or a dealer. The numbers reflect the measurement only. We give no buying or selling advice.

Valid until 2027/03/18

This is a sample. The values are not from a real car.

What you getDigital certificate + battery test card

The digital certificate is the page that goes on the listing. Scan the test card or enter the full VIN at the car and it opens: VIN, test date, measured capacity and the charge curve, and it prints as a PDF.

Dealers and buyersWhy they use CELLPROOF

I'm selling

  • 5-minute EV battery reportNo waiting, no guesswork: a battery state-of-health report on the lot.
  • Better trade-in accuracyAppraise used EVs on measured data and avoid undervaluing or costly mistakes.
  • Build buyer trustPut a transparent battery report on the listing and close more easily.

I'm buying

  • Avoid a costly mistakeA new battery in Taiwan runs about NT$400,000 to 700,000. Know the battery's real state before you pay.
  • Negotiate with dataA weaker battery is a reason to talk price.
  • Anyone can check itThe report is bound to the VIN and verified online. Not the seller's word.

Want to know how we measure? See the method

Process

How the test worksTwo tests, three steps each

About 5 minutes per car

Connect to the diagnostic port

The tester comes to your home or an agreed place and connects the reader to the car's diagnostic port.

Areas

Service areasThe tester comes to you

We currently test on site in these areas.

Outside these areas? Ask us on LINE first.

Common questions

What is the difference between SWIFT and DEEP?

SWIFT takes a few minutes. It checks the battery for anything clearly wrong, but it does not measure capacity, and the health figure is the one the car itself reports. DEEP takes a night. It measures how much capacity the battery actually has left and sets that against the car's own figure. Choose SWIFT to rule out problems quickly while viewing a car. Choose DEEP when you want the real picture before you pay.

How is Cellproof different from a dealer reading SoH with a scan tool?

A scan tool reads the number the car worked out for itself, which can be off after a reset or because of how the car has been used. DEEP works the capacity out again from the raw voltage and current, and prints both numbers side by side on the certificate. When the gap is large, there is something about that car worth asking about.

Can the test harm my car?

No. The equipment only reads data. It sends no commands to the car and changes no settings. On some models interior trim has to be removed and refitted to reach the diagnostic port, and we do that carefully.

If the result is bad, will it be made public?

No. Whether a certificate is public is entirely your decision. If the result is not what you hoped, only you see the report.

How do I know a certificate is real?

Two ways. Scan the QR code on the certificate or badge and it opens the original certificate on our website; or go to verify and enter the full 17-character VIN from under the windscreen. Once it is open, check the last 8 characters of the VIN and the mileage against the car. If both match, it is this car's certificate.

Which vehicles do you cover?

Some model years of the Tesla Model 3 and Model Y for now. Other brands are being prepared. The full list is on the covered vehicles page.

For more detail, see the test method

Buying or selling a car?Check the battery first.

Two tests, SWIFT and DEEP, from NT$1,400. The tester comes to you.

Book a test