Cameron Sino 6AV3 900mAh 3.0V replacement battery

Siemens PLC replacement battery

The Cameron Sino 6AV3 is a 900mAh 3.0V lithium cell built to replace the original backup battery in Siemens Simatic S7-300, S7-400, S5-90U, S5-95U, S7-200 and SL series programmable logic controllers. It matches the OEM part numbers 6AV3 972-1XBOO-OAOO, 6ES7971-1AAOO-OAAO and 575332TA so the CPU retains its program and clock data during power loss.

Simple two-wire connector swap

The pack uses the same keyed two-pin connector as the factory unit, so installation is a matter of unplugging the old cell and pressing the new one into the socket on the CPU board. The most common issue is reversing the polarity; the plug only fits one way, but forcing it can bend the header pins. A second pitfall is leaving the controller powered while swapping the battery, which can erase the stored program.

Limited to 3.0V backup rail

The cell supplies a fixed 3.0V to the CPU’s real-time clock and RAM retention circuit; it cannot power I/O modules, communication processors or the main logic supply. Capacity is 900mAh (2.70Wh), which typically provides several years of data retention but will not support cyclic write-heavy applications that demand a higher continuous current. The chemistry is not rechargeable, so the PLC must remain on mains power for normal operation.