LifePo4 Battery Charger Protection Module (BMS) 4S 30A 12V Common Port with Balancing

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LifePo4 Battery Charger Protection Module ( BMS ) 4S 30A 12V Common Port with Balancing Compact 4-series (4S) 12V LiFePO4 battery protection module (BMS), model CF-D34S30A-B , measuring 62 × 45 × 1.5 mm as printed on the PCB. The board combines a common-port charge/discharge path ( C- / B- solder pads with exposed tinned traces for high-current wiring), a white multi-pin balance connector carrying the cell taps ( B+, B3, B2, B1 ), twelve onboard MOSFETs with low-resistance R005 (0.005 Ω) current-sensing resistors for the 30 A rating, and a dedicated QFP control IC with a passive balancing network. Four corner mounting holes and an optional switch footprint (marked 开关) complete the layout. Sold as the bare board exactly as pictured. Features 4S LiFePO4 protection – cell tap labels B+, B3, B2, B1 confirm 4-cell series configuration (12V class). Common-port design – single C- terminal pad alongside B- for charge/discharge return wiring. 30 A current path – model designation “4S30A”; implemented with 12 onboard MOSFETs and parallel R005 (0.005 Ω) sense resistors. Onboard cell balancing – passive balancing network (SOT-23 switching transistors with “102” resistor array) driven by a dedicated QFP control IC. High-current solder rails – exposed tinned trace strips on the C- and B- rails for wire soldering / adding solder mass. Balance connector – white multi-pin socket for the cell-tap harness (B+, B3, B2, B1). Optional switch footprint – pad pair silkscreened 开关 (switch) for an external on/off switch. Easy mounting – 4 corner mounting holes; compact 62 × 45 × 1.5 mm green PCB. Clear identification – model CF-D34S30A-B and batch code 21K05 printed on board for traceability. Specifications Model / Part Number CF-D34S30A-B (printed on PCB) Board / Batch Code 21K05 Battery Chemistry LiFePO4 (Lithium Iron Phosphate) Series Configuration 4S (4 cells in series) Nominal System Voltage 12 V Continuous Current Rating 30 A Port Type Common port (shared charge/discharge negative, C-) Cell Balancing Yes – onboard passive balancing network Weight 15 g Main Terminals Solder pads C- and B- with exposed tinned traces Cable Length 35 cm Extra Footprint Switch pad (marked “开关” / switch) PCB Dimensions 62 × 45 × 1.5 mm (printed on PCB) Mounting 4 × corner mounting holes PCB Color Green Applications Protection and balancing of DIY or refurbished 4-cell (12V) LiFePO4 battery packs . 12V backup/UPS and small solar-storage / solar-lighting battery modules. RV, caravan and marine auxiliary 12V lithium packs (within the 30A rating). Portable power boxes, LED lighting packs, alarm and backup systems using 4S LiFePO4 cells. Replacement protection board for existing 4S LiFePO4 packs where size (62×45 mm) and 30A rating match. Package Content 1 x LifePo4 Battery Charger Protection Module (BMS) 4S 30A 12V Common Port with Balancing 1 x Balance harness cable