Stop pulling caps and guessing water levels on every cell. The Flow-Rite Pro-Fill system replaces your existing vent caps with automatic shut-off valves, links all cells with tubing, and lets you fill an entire 48V battery bank from a single connection point -- in a fraction of the time it takes to do it manually.
Properly watered lead-acid batteries last significantly longer -- but checking and topping 18 individual cells (six 8V batteries, three cells each) is tedious, messy, and easy to skip. The Flow-Rite Pro-Fill BG-U48V-6G-WS eliminates that excuse. Each automatic shut-off valve seats directly in place of your existing vent cap and stops flow the moment the electrolyte reaches the correct level. No overflow, no dry cells, no acid on your hands.
All six batteries are interconnected with Flow-Rite's pre-cut tubing, so a single fill point handles the entire bank. The included hand pump lets you pressurize from a standard water jug without any external water source or power. It is an ideal solution for RVs, golf carts, floor scrubbers, and any 48V deep-cycle battery application where this 2.5in cell-spacing configuration applies.
Each valve stops water flow precisely at the correct electrolyte level -- no overfilling, no guesswork.
One connection fills all 18 cells across six 8V batteries simultaneously through pre-routed tubing.
Fill from any standard water jug anywhere -- no plumbed water supply or electrical hookup required.
Valves thread directly into existing vent cap openings -- no drilling, cutting, or battery modification needed.
Overfilling a lead-acid battery dilutes the electrolyte, corrodes terminals, and can cause acid overflow onto battery trays and cables. Flow-Rite's float-valve mechanism shuts off each cell individually, so a cell that is already near-full will stop accepting water while adjacent cells continue to fill. Every cell ends up at the correct level -- every time.
This kit is engineered specifically for batteries with 2.5 inches of center-to-center cell spacing. Flow-Rite offers multiple Pro-Fill configurations for different cell spacings (1.5in, 2in, 2.5in, and others). Measure the distance between the center of adjacent vent cap openings on your specific battery before ordering. Using tubing cut for the wrong spacing will result in kinked lines or pulled fittings.
The Pro-Fill system is designed for flooded (wet cell) lead-acid batteries that require periodic water addition. It is not compatible with sealed AGM, gel, or lithium batteries, which do not have vent cap openings and do not require watering. Common 8V flooded batteries used in 48V golf cart and RV house bank configurations include Trojan T-875, US Battery US8VGC, Crown 8V-GC series, and similar models -- verify vent cap thread size matches Flow-Rite's valve spec before installing.