J721 100W Strap Cable Power Bank 20000mAh | OEM

Description

J721 Power Bank combines 20000mAh capacity, 100W fast charging, and a built-in Type-C strap cable for high-power mobile charging.

Frequently Asked Questions: J721 100W Strap Cable Power Bank

1. What specifications are confirmed for the J721?

The published J721 specification lists a 20000mAh capacity, a 153.7 × 73.5 × 26.8mm body, Type-C port and built-in Type-C strap-cable input profiles up to 20V/3.25A, output profiles up to 20V/5A, and a USB-A output with profiles up to 10V/2.25A. Final rated energy in watt-hours, weight, material, cell configuration, labeling, and port behavior should be confirmed on the approved production datasheet.

2. What is confirmed about the J721 100W output and strap cable?

The Type-C port and built-in Type-C strap cable list an output profile of 20V/5A, which equals a maximum profile of 100W. The input profiles are different and reach 20V/3.25A. The published specification does not independently confirm the cable conductor size, identification electronics, connector certification, or sustained-load temperature. Buyers should verify the supported protocol, cable and connector rating, target-device negotiation, voltage drop, bend durability, temperature rise, and protection response on the approved sample.

3. What devices can use the J721 Type-C output?

Actual charging depends on the negotiated protocol, cable, device input requirements, battery state, temperature, and power allocation. A listed 20V/5A profile does not guarantee that every phone, tablet, handheld device, or laptop will accept 100W or charge at a particular speed. Buyers should test the exact target-device list and record negotiated voltage, current, charging time, temperature, and behavior at different battery levels before publishing compatibility claims.

4. How many device charges can the J721 provide?

The current specification lists 20000mAh but does not publish the final rated energy in watt-hours or measured usable output energy. Charge count varies with cell voltage, conversion efficiency, output voltage, cable loss, temperature, battery age, output power, and the target device’s charging behavior. Buyers should request the final cell and nameplate data, measured discharge-energy results, and device-charge tests with stated conditions before publishing phone or laptop charge-count estimates.

5. What thermal and sustained-output evidence should J721 buyers request?

The current specification does not publish the internal thermal materials, sensor layout, control thresholds, ventilation design, or verified duration at maximum output. Buyers should request temperature-rise curves at each major output profile, sustained-load and cycling results, connector and cable temperatures, ambient test conditions, derating behavior, protection thresholds, abnormal-load testing, and test reports for the final PCBA, battery, cable, and enclosure.

6. What safety and transport evidence should J721 buyers request?

Buyers should request the final watt-hour rating, battery and transport documents, electrical-safety and EMC reports, protection test results, material declarations, labeling files, and model traceability for the production configuration. Passenger-travel acceptance cannot be determined from the 20000mAh value or 100W output alone; it depends on the verified watt-hour label, documentation, packaging, current rules, and the carrier’s requirements.

7. What OEM and ODM options are available for the J721?

Standard OEM service starts at 500 pieces for logo and packaging on the existing J721 platform. Light customization, such as an approved shell color, documentation, or packaging change, generally starts at 1,000 pieces. Cable, battery, PCBA, firmware, thermal design, connector system, display, or structural changes are deeper ODM work and generally start at 2,000 pieces. Final MOQ, color and packaging feasibility, samples, tooling, lead time, and certification scope must be confirmed in the quotation.