Check chargers and cables with KM003C

What you can check and what you need

Read advertised voltage, current and power capabilities (PDOs), higher-power EPR and information reported by a cable (SOP’). Record charging voltage/current, integrate Wh and mAh, and export reports.

Hardware use needs a KM003C, PC, a data-capable USB cable for the PC connection and a USB PD charger to test. Direct connection requires a compatible desktop browser such as Chrome or Edge with the necessary WebUSB and Web Serial support. Windows USB configuration may require WinUSB driver setup.

The standard browser connection requires no CLI or Python installation. Demos and saved-log viewing work without the meter.

First connection: leave OUT empty and the load off

1. Open “Connect KM003C and diagnose” in PowerChecker.
2. Choose the KM003C using “1. Allow USB”.
3. Use “2. Allow Serial” to choose the Serial port of the same KM003C.
4. Press “3. Read charger + cable information”. Permission alone does not start acquisition.

The query initializes PD and exchanges messages. Additional EPR information may take time; no-load acquisition waits beyond the initial SPR menu.

Does a 240 W PDO mean charging at 240 W now?

No. PDOs describe the conditions advertised by the charger. For example, 48 V at 5 A advertises up to 240 W under that condition. Actual consumption depends on the device, supported charging method, battery level, temperature and cable.

SPR is the standard power range; EPR supports higher power. PPS and AVS allow voltage adjustment. Seeing 28–48 V EPR entries does not mean you manually requested that voltage. Missing entries alone do not establish lack of support.

When cable identity is unavailable

Captive and other cables may not return identity information. Missing information alone does not establish a fault. For detachable cables, the e-marker, orientation, VCONN power, connection and KM003C firmware can affect reception.

“Read cable identity again” retains the previous charger capability table and measurement. After changing connections, refresh charger information too. Cable fields are reported claims, not a load test or certification.

Check slow charging or power interruptions

Reading charger information does not measure charging conditions. Once the query finishes, connect a compatible phone or PC for actual power delivery and record about 10 seconds using the charging voltage/current recording control.

“Check charging conditions” presents the result and next steps. A hot device or nearly full battery may draw much less than the charger maximum. Switching voltage or making connections can also cause changes; this result alone does not establish a fault. Detailed evidence remains available in the expandable section.

Quick diagnosis versus Pro control

Quick diagnosis has no manual voltage requests or sweep controls. Charger and cable queries still initialize PD; this is not a passive-only mode. Turn off the external load while querying information.

Pro control & sweeps includes manual voltage requests and PPS / AVS sweeps. Before using higher voltages, verify that every connected device, cable and load supports the requested voltage.

Save recordings and reports

Use JSON backups to retain and reopen source data. PNG, HTML and Markdown reports are available for sharing. Saved sessions belong to the current browser and site storage; export important recordings as JSON for long-term storage.

See the English usage documentation for full features and CLI setup, or PD-Interpreter to read USB PD messages as conversations.