1. Product Overview
The YUSTDA Car Charger Adapter is a high-quality power supply designed to provide reliable power to your OTO ER-839S Electro-Reflexologist Foot Massage device directly from your vehicle's cigarette lighter socket. This adapter ensures your device remains powered during travel, offering convenience and portability.

A black car charger adapter with a cigarette lighter plug on one end and a barrel connector on the other, connected by a black cable. This is the YUSTDA Car Charger Adapter.
Key Features:
- 100% Brand New, High Quality Car Power Charger/Adapter.
- DC Input 12-24V, suitable for most vehicle power outlets.
- Built-in Dynamic IC, Charger IC & Power fuse for rapid charging and overcharge protection.
- Manufactured with the highest quality materials, ensuring durability and performance.
- Certified with FCC, CE, and RoHS standards for safety and environmental compliance.
2. Safety Information
Your safety is paramount. This YUSTDA Car Charger Adapter incorporates multiple safety features to protect both the adapter and your connected device.

A visual representation of the adapter's safety features, including icons for over-temperature, over-voltage, over-current, and short-circuit protection.
Safety Features:
- Over Current Protection: Prevents damage from excessive current flow.
- Total Power Protection: Safeguards against power surges and fluctuations.
- Over Voltage Protection: Protects against damage from input voltage exceeding safe limits.
- Short Circuit Protection: Automatically shuts down power in case of a short circuit.
Always ensure the adapter is used in a well-ventilated area and avoid exposing it to moisture or extreme temperatures. Do not attempt to disassemble or modify the adapter.
3. Setup
Follow these simple steps to set up your YUSTDA Car Charger Adapter:
- Identify Vehicle Lighter Socket: Locate the 12V or 24V cigarette lighter socket in your vehicle. Ensure it is clean and free of debris.
- Insert Adapter: Firmly insert the car charger adapter's plug into the vehicle's lighter socket. Ensure it is fully seated for a stable connection.
- Connect to Device: Plug the barrel connector end of the adapter cable into the power input port of your OTO ER-839S Electro-Reflexologist Foot Massage device.
Once connected, the adapter is ready to supply power to your device.
4. Operating Instructions
Operating the YUSTDA Car Charger Adapter is straightforward:
- Ensure the adapter is correctly plugged into the vehicle's lighter socket and your OTO ER-839S device.
- Turn on your vehicle's ignition if the lighter socket requires it for power.
- Power on your OTO ER-839S device as per its own instruction manual. The adapter will provide the necessary power.
- When not in use, it is recommended to unplug the adapter from the vehicle's socket to conserve battery power, especially if the socket remains active when the ignition is off.
5. Maintenance
Proper maintenance ensures the longevity and optimal performance of your car charger adapter:
- Cleaning: Use a soft, dry cloth to wipe the adapter clean. Do not use liquid cleaners or solvents.
- Storage: Store the adapter in a cool, dry place away from direct sunlight and extreme temperatures when not in use.
- Inspection: Periodically inspect the cable and connectors for any signs of damage, fraying, or bending. If any damage is observed, discontinue use immediately.
- Avoid Stress: Do not pull the cable forcefully or bend it sharply, especially near the connectors, as this can damage internal wiring.
6. Troubleshooting
If you encounter issues with your YUSTDA Car Charger Adapter, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Adapter not providing power. | Loose connection; Vehicle lighter socket fuse blown; Vehicle ignition off. | Ensure adapter is firmly seated. Check vehicle's fuse box for lighter socket fuse. Turn vehicle ignition on. |
| Device not charging/powering on. | Adapter not connected to device; Device power input issue; Incompatible device. | Verify the adapter's barrel connector is fully inserted into the device. Test the device with its original power supply if available. Ensure the device is compatible with a 12-24V DC input. |
| Adapter feels excessively hot. | Overload; Poor ventilation; Internal fault. | Unplug immediately. Ensure adapter is not covered. If problem persists, discontinue use and contact support. |
7. Specifications
- Product Type: Car Charger Adapter
- Brand: YUSTDA
- Input: DC 12-24V
- Output: DC (Specific voltage/current designed for OTO ER-839S, please refer to your device's power requirements)
- Certifications: FCC, CE, RoHS
- ASIN: B07ZKF9SCZ
- Date First Available: October 25, 2019
8. Warranty and Support
For warranty information, please refer to the specific terms and conditions provided by the seller at the time of purchase. Warranty coverage typically addresses manufacturing defects.
Should you have any questions, concerns, or require technical assistance with your YUSTDA Car Charger Adapter, please do not hesitate to contact our customer support team:
- Email: epcustomerservice@yahoo.com
Please provide your product model (Car Charger Adapter for OTO ER-839S) and a detailed description of the issue when contacting support to facilitate a quicker resolution.