1. Introduction
This manual provides essential information for the safe and efficient operation, installation, and maintenance of your Mjbsan 12V 320Ah LiFePO4 RV Battery. Please read this manual thoroughly before using the product to ensure optimal performance and longevity.
Figure 1: Mjbsan 12V 320Ah LiFePO4 RV Battery with accessories and app interface.
2. Safety Information
WARNING: Failure to follow these safety instructions may result in electric shock, fire, serious injury, or death.
- Do not disassemble, modify, or puncture the battery.
- Keep the battery away from fire, heat sources, and direct sunlight.
- Do not immerse the battery in water or other liquids.
- Use only compatible chargers and charging methods.
- Ensure proper ventilation during charging and discharging.
- Wear appropriate personal protective equipment (PPE) when handling the battery.
- In case of fire, use a Class D fire extinguisher. Water can exacerbate lithium battery fires.
- Disconnect the battery using the integrated disconnect switch before performing any maintenance or connections.
3. Product Features
- High Capacity: 12V 320Ah LiFePO4 battery with 4096Wh usable energy.
- Robust Construction: Features a high-quality metal housing for impact and wear resistance, and improved heat dissipation.
- Integrated BMS: Built-in 250A Battery Management System (BMS) provides protection against overcharging, over-discharge, over-current (250A), over-temperature, and short circuits. Includes low-temperature shutdown protection (charging at ≤0°C, discharging at ≤-20°C).
- Monitoring: Equipped with a 2.8-inch Bluetooth LCD screen for real-time monitoring of battery percentage, voltage, current, and capacity. A Bluetooth app function allows smartphone monitoring.
- Expandability: Supports connection of up to 2 units in series for a 24V system (for Victron communication) or up to 4 series and 4 parallel (4P4S) for a 51.2V 1280Ah system without Victron communication.
- Long Lifespan: Offers 4000+ cycles at 100% Depth of Discharge (DOD) and 8000+ cycles at 80% DOD, providing a 10-year lifespan.
- Communication: Compatible with Victron System communication protocol for enhanced energy management.
Figure 2: The 250A BMS provides comprehensive protection for the battery.
4. What's in the Box
- 1 x Mjbsan 12V 320Ah LiFePO4 Battery
5. Setup and Installation
5.1 Pre-Installation Checks
- Inspect the battery for any physical damage.
- Ensure all connections are clean and free of corrosion.
- Verify that your charging system (solar charger, inverter, etc.) is compatible with LiFePO4 batteries and can handle the battery's voltage and current requirements.
5.2 Connection Guidelines
- Ensure the battery's disconnect switch is in the OFF position.
- Connect the positive (+) terminal of the battery to the positive terminal of your load/charging system.
- Connect the negative (-) terminal of the battery to the negative terminal of your load/charging system.
- Ensure all connections are tight and secure.
- If connecting multiple batteries in series or parallel, refer to the 'Capacity Extension' section for specific instructions.
- After all connections are made, turn the battery's disconnect switch to the ON position.
Figure 3: Example of a solar system connection with the Mjbsan 12V 320Ah LiFePO4 battery.
5.3 Capacity Extension (Series/Parallel)
The Mjbsan 12V 320Ah LiFePO4 battery offers flexibility for system expansion:
- Series Connection: Only supports connecting 2 units in series to form a 24V system when communicating with a Victron system.
- Parallel Connection: If not communicating with a Victron system, batteries can be expanded to a maximum of 4 series and 4 parallel (4P4S) to form a 51.2V 1280Ah battery system.
Important: Always ensure all batteries in a series or parallel bank are of the same brand, model, and capacity, and are at a similar state of charge before connecting.
6. Operating Instructions
6.1 Powering On/Off
Use the integrated disconnect switch on the battery to power the unit on or off. Turn the switch to the ON position to activate the battery and to the OFF position to deactivate it.
6.2 Charging
Charge the battery using a compatible LiFePO4 charger. The BMS will protect against overcharging. The low-temperature shutdown feature will intelligently stop charging if the battery temperature is ≤0°C.
6.3 Discharging
The battery can power high-power appliances such as air conditioners, TVs, and ovens. The BMS will prevent over-discharge. The low-temperature shutdown feature will stop discharging if the battery temperature is ≤-20°C.
Figure 4: Estimated run times for common RV appliances.
6.4 Monitoring (LCD Screen & APP)
The battery features both an integrated LCD screen and a Bluetooth app for real-time monitoring:
- LCD Screen: View battery percentage, voltage, current, and capacity directly on the 2.8-inch screen.
- Bluetooth App: Download the Mjbsan app to monitor and manage battery performance from your smartphone.
Tip: The Bluetooth battery can only connect to one device at a time. When using the LCD monitor, please disconnect the Bluetooth of the mobile APP first.
Figure 5: Real-time monitoring via LCD screen and smartphone app.
7. Maintenance
- Regular Inspection: Periodically check the battery terminals for cleanliness and tightness. Clean any corrosion with a wire brush and baking soda solution, then rinse with distilled water and dry thoroughly.
- Storage: If storing the battery for an extended period, ensure it is charged to approximately 50-70% State of Charge (SOC) and stored in a cool, dry place. Disconnect all loads.
- Temperature: Avoid operating or storing the battery in extreme temperatures outside its specified range.
- Firmware Updates: Check the Mjbsan website or app for any available firmware updates for the BMS.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Battery not charging | Disconnect switch off; Charger not connected; Charger fault; Low temperature protection active. | Turn disconnect switch ON; Check charger connection; Verify charger functionality; Move battery to warmer environment (above 0°C). |
| Battery not discharging/no power output | Disconnect switch off; Over-discharge protection active; Low temperature protection active; Short circuit. | Turn disconnect switch ON; Recharge battery; Move battery to warmer environment (above -20°C); Check for short circuits in wiring. |
| Bluetooth app not connecting | LCD screen active; Bluetooth off on phone; App not updated. | Ensure LCD screen is off or not actively monitoring; Enable Bluetooth on your smartphone; Update the Mjbsan app to the latest version. |
| Unusual heat from battery | Overload; Internal fault. | Reduce load; Disconnect battery immediately and contact customer support. |
9. Specifications
| Feature | Detail |
|---|---|
| Model | MJ-12V320-TH |
| Nominal Voltage | 12V |
| Nominal Capacity | 320Ah |
| Usable Energy | 4096Wh |
| Max Load Power | 3200W |
| BMS | 250A (Built-in) |
| Cycle Life | 4000+ cycles @100% DOD, 8000+ cycles @80% DOD |
| Lifespan | 10 Years |
| Low Temperature Charge Cutoff | ≤0°C |
| Low Temperature Discharge Cutoff | ≤-20°C |
| Dimensions (L x W x H) | 14.17 x 12.2 x 6.29 inches (360mm x 310mm x 160mm) |
| Item Weight | 69 pounds |
| Terminal Type | M6 Terminals |
| Monitoring | 2.8-inch Bluetooth LCD screen & Smartphone APP |
| Communication Protocol | Victron System (supported for 2P series connection) |
Figure 6: Physical dimensions and M6 terminal detail.
10. Warranty and Support
Mjbsan provides a five-year warranty for all batteries. For any questions or support needs, please contact Mjbsan customer service. Our professional customer support team is available 24 hours to assist you.
For warranty claims or technical assistance, please refer to the contact information provided with your purchase or visit the official Mjbsan website.