YX850 Emergency Power Failure Automatic Switching Lithium Battery Module 5V-48V

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*Disclaimer: The images are merely illustrative.

The YX850 is an automatic power switching module designed for emergency power and backup battery applications.

Under normal conditions, the load is powered by the main DC supply connected to the DC+ and DC- terminals. When the main power supply fails, the module automatically switches the load to the backup battery connected to BAT+ and BAT-. When the main power is restored, the system automatically switches back to the primary DC supply.

The module supports a wide voltage range from 5 V to 48 V DC, provided that the main supply, battery and load are compatible with the same operating voltage. The YX850 does not perform voltage conversion.

Key Features

Operation

The YX850 has three main terminal groups:

Normal operation

When power is available at DC+ / DC-, the main DC source powers the connected load through OUT+ / OUT-. The module gives priority to the primary power source.

Power failure

When the main DC supply is interrupted, the YX850 automatically switches the load to the backup battery connected to BAT+ / BAT-.

Power restoration

When the main power supply returns, the module automatically switches the load back to the primary DC source.

Wiring

              MAIN DC POWER SUPPLY
                    +       -
                    │       │
                  DC+     DC-
                    │       │
              ┌───────────────┐
              │     YX850     │
              │               │
BACKUP ───── BAT+           OUT+ ─── + LOAD
BATTERY      BAT-           OUT- ─── - LOAD
              │               │
              └───────────────┘

DC+ / DC- → main power supply
BAT+ / BAT- → backup battery
OUT+ / OUT- → load/device

Correct polarity must be observed for all connections.

Battery charging

The YX850 can allow the main DC source to provide charging current to the connected battery through its circuit. However, the YX850 should not be considered an intelligent lithium battery charger.

Charging parameters depend on the external power supply/charger, battery and system configuration. For lithium batteries, an appropriate BMS/charger designed for the specific battery chemistry and cell configuration should be used.

One technical reference states that charging current passes through a diode, causing an approximately 0.78 V voltage drop.

Switching time

The YX850 uses a mechanical relay, so switching is not instantaneous like a MOSFET-based electronic UPS.

Several product references specify a power interruption of approximately 0.7 seconds during source switching.

Therefore, the module should not be considered suitable for equipment that cannot tolerate an interruption of this duration, unless additional energy storage is provided.

Voltage requirement

The main power supply, battery and load must operate at the same nominal voltage.

For example, for a 12 V system:

• Power supply → 12 V DC
• Battery → compatible 12 V battery
• Load → 12 V DC

The module does not convert 12 V to 24 V or 24 V to 12 V.

Applications

• DC UPS systems
• Emergency power systems
• Network equipment
• Routers and modems
• Security systems
• Emergency lighting
• Control systems
• Arduino projects
• Raspberry Pi
• IoT
• Automation
• Battery-powered equipment
• 5 V, 12 V, 24 V or 48 V DC systems

Package contents

Important warnings

• Use DC power only, within the 5–48 V range.
• Observe correct polarity.
• Do not connect AC power directly to the module.
• The main supply, battery and load must use the same operating voltage.
• Maximum specified load current is 10 A.
• The module does not replace a proper BMS or lithium battery charger.
• A switching interruption of approximately 0.7 seconds is reported for this module family.