Stop pulling vent caps and manually topping off each cell. The Pro-Fill system replaces your existing vent caps with automatic shut-off valves interconnected by tubing, so you fill every cell to the correct level in a single step -- no overfilling, no spills, no guessing. This kit is engineered for battery banks where cells are not evenly spaced and no inter-battery manifolds are used.
The Flow-Rite Pro-Fill BG-U12V-4G is built for RV owners, boondockers, and anyone running a bank of flooded lead-acid or AGM-style batteries where the cells are not at standard, uniform spacing. Each kit includes automatic float-style shut-off valves that thread directly into the existing vent cap holes. The valves are pre-connected with flexible tubing so water flows through the entire bank until each cell reaches its proper level -- then the valve shuts off automatically.
Because this kit does not include manifold connectors (the rigid links that bridge between adjacent batteries), it works where standard manifold-style kits cannot -- non-uniform spacing, mixed battery layouts, or banks where each battery sits at a different angle or height. Tubing length between valves can be cut to fit your exact installation.
Float valves stop water flow precisely at the correct electrolyte level -- no overwatering, no dry cells.
Designed to work with 12V electric watering pumps (sold separately) for hands-free, walk-up filling.
Flexible tubing connections instead of rigid manifolds let this kit fit non-standard and uneven battery layouts.
Shut-off valves thread into standard vent cap openings on most flooded lead-acid 6V and 12V batteries.
Each automatic shut-off valve replaces one existing vent cap. Inside the valve, a float mechanism rises with the electrolyte level. When the cell is full, the float seats and stops flow -- just like a toilet tank valve. All valves in the bank are linked by flexible tubing from a single inlet point, so one connection from your water source (hand pump, 12V electric pump, or pressurized supply) fills every cell simultaneously.
The 12V designation on this kit refers to battery system voltage compatibility (12-volt battery banks), not the pump voltage. The system is passive once installed -- the pump or water source provides pressure; the valves do the controlling.
Standard Pro-Fill kits use rigid manifold bridges that clip from battery to battery at fixed center-to-center distances. If your batteries are different sizes, mounted at varying heights, or spaced irregularly in a compartment, those manifolds simply will not reach. The BG-U12V-4G replaces the rigid manifold links with flexible tubing -- cut to any length -- so it adapts to virtually any physical layout without shimming or repositioning your battery bank.
This kit provides the valves and tubing only. A 12V electric pump, hand pump, or pressurized water source is required to move water through the system. Flow-Rite and compatible third-party 12V pumps are available separately. Use distilled or deionized water only -- tap water mineral content shortens battery life.