Stop pulling caps and checking individual cells. The Flow-Rite Pro-Fill system interconnects all cells across four 12V deep-cycle batteries so you can water every cell from a single fill point -- automatically stopping at the correct level every time.
Deep-cycle batteries used in RVs, solar storage banks, golf carts, and floor scrubbers demand regular, precise watering to maintain capacity and extend cycle life. Underfilling leaves plates exposed; overfilling pushes electrolyte out of the vents and corrodes terminals. Both problems shorten battery life significantly.
The Flow-Rite Pro-Fill BG-U48V-1A eliminates both risks. Automatic float shut-off valves replace each factory vent cap and stop water flow the instant electrolyte reaches the correct level inside that cell. A single external fill point connects to all valves through low-profile interconnect tubing, so one water gun or pump connection tops off every cell in seconds -- no prying caps, no guessing, no spills.
This universal kit is configured for four (4) 12V batteries with 2.7-inch center-to-center cell spacing, which is the standard spacing found on many Group 27, Group 31, and similarly sized deep-cycle batteries common in RV house banks and solar off-grid systems.
Float valve stops flow at the correct electrolyte level -- no overfill, no dry plates.
One connection waters all cells across all four batteries simultaneously.
Designed for standard 2.7-inch cell-spacing deep-cycle batteries -- no proprietary hardware required.
Valves thread directly into the existing vent cap openings -- no drilling or modifications needed.
The BG-U48V-1A is a complete, ready-to-install kit. Contents include:
Note: A fill pump or water gun (sold separately) is required to introduce water into the system. Flow-Rite offers compatible hand pumps and battery fill guns that attach to the single fill port.
Flooded lead-acid and AGM-hybrid deep-cycle batteries lose water through normal charge/discharge cycles, especially in warm climates or under heavy use. Most manufacturers recommend checking and topping cells every 4-6 weeks during active use. The Pro-Fill system makes that routine take under 60 seconds for the entire bank -- dramatically improving compliance and battery longevity.
The 2.7-inch cell spacing on this kit refers to the center-to-center distance between adjacent vent cap openings on each battery. Before ordering, measure your batteries. Flow-Rite offers kits in multiple cell-spacing configurations (for example, kits designed for 1.5-inch, 2.0-inch, and other spacings) as well as kits for different battery counts. If your spacing does not match 2.7 inches, select the correct kit to ensure the pre-cut tubing reaches each cell without tension or slack.
The Pro-Fill system is designed for flooded (wet cell) lead-acid batteries that require periodic water addition. Do not use this system on sealed AGM or gel-cell batteries -- those battery types are maintenance-free and have no serviceable vent openings. Installing fill valves on sealed batteries will damage them.