leagend JS300 PRO: One System. Two Ways to Start.
Always installed and ready for everyday protection. Clip-on ready for emergency rescue.
About This Project
leagend JS300 PRO is a battery-free smart jump starter built around supercapacitor technology. Permanently install it on your vehicle's 12V starting battery, and JS300 PRO can monitor the battery and starting system, manage its own charging and standby behavior, and automatically provide starting assistance when needed. The device can be used as a traditional jump starter by installing the included alligator clamps, and can also be used as a clip-on rescue starter for another compatible vehicle. The device includes a wireless dashboard display and display-based Force Start, and can monitor battery voltage, estimated CCA and battery health. It is designed to reduce repeated starting stress and provide different recovery paths depending on the vehicle battery's condition.
Key Highlights
Technical Specs
| Spec | Details |
|---|---|
| Voltage | 12V |
| Peak Current | Up to 1,000 A |
| Supercapacitor Cells | Five 3.0 V / 600 F cells |
| Capacity | Approximately 120F |
| Energy Storage | About 13,500 joules (3.75Wh) |
| Price | $999 |
| Price (USD) | Estimated $1,200 |
| Currency | USD |
| Backers | null |
| Description | Supercapacitor-based starting power |
Reward Tiers
Risks & Challenges
No high-energy lithium battery in the starting unit, but may not be able to operate from the vehicle system if the vehicle battery falls below approximately 5V.
Project Insights
Development progress, shipping timeline, and announcements
View all updates ↗
