Stop wrestling with vent caps and a funnel on every watering day. The BG-U24V-4J drops automatic shut-off valves into each cell, links them with pre-cut tubing, and lets you fill your entire 24V bank -- four 6V batteries, all cells -- in a single connection. Designed specifically for batteries with non-standard spacing where a rigid manifold rail will not fit.
Maintaining proper electrolyte levels in flooded lead-acid batteries is one of the most critical -- and most neglected -- RV maintenance tasks. Overfilling causes acid spills and corrosion; underfilling degrades plates and shortens battery life. The Flow-Rite Pro-Fill system takes the guesswork out by building automatic shut-off directly into each cell valve. Water flows freely until the correct level is reached, then the valve closes. You cannot overfill.
The BG-U24V-4J is the universal, no-manifold version of the 24V Pro-Fill lineup. Instead of a rigid rail that requires batteries to be in a fixed, evenly spaced configuration, this kit uses flexible interconnect tubing that routes between batteries regardless of their arrangement in your battery compartment. If your 6V golf-cart-style batteries are offset, angled, or simply spaced farther apart than a standard tray allows, this is the correct kit.
Each valve seals automatically at the correct electrolyte level -- no overfill, no spill, no guessing.
Flexible tubing connects all cells without a rigid manifold, fitting non-standard battery spacing and compartment layouts.
Valves thread directly into standard battery vent openings -- no drilling, no permanent modifications.
Attach a single water supply line and all eight cells (four batteries x two cells each) fill simultaneously.
Each automatic shut-off valve replaces a standard vent cap on the battery. Inside the valve is a float mechanism calibrated to the correct electrolyte level for that cell. When you connect a water supply -- either a hand pump, a gravity-feed bottle, or Flow-Rite's powered pump -- water travels through the interconnecting tubing and into each cell. As the electrolyte reaches the set level, the float rises and seats against the inlet port, stopping flow to that cell. Once all cells are satisfied, back-pressure stops the pump or signals you to disconnect. The process typically takes under 30 seconds for a four-battery bank.
Flooded lead-acid batteries lose water during charging through electrolysis. Regular watering maintains plate coverage, which directly affects amp-hour capacity and cycle life. The Pro-Fill system makes this a quick weekly or monthly habit rather than a 15-minute chore with a flashlight and a turkey baster.
The BG-U24V-4J is designed for flooded (wet cell) lead-acid batteries that require periodic electrolyte top-off. Common RV applications include:
Not intended for AGM, gel, or lithium batteries -- those chemistries are sealed and do not require water addition.
Flow-Rite offers Pro-Fill kits by voltage and battery count. The BG-U24V-4J covers a 24V system built from four 6V batteries with non-standard or irregular spacing. If your batteries sit in a uniform, evenly spaced tray, a manifold-style kit (such as the BG-U24V-4 with manifold) may provide a neater installation. If you are running a 12V system or a different battery count, select the corresponding kit for your configuration.
Installation requires no special tools beyond a rag and basic hand-tightening. The process follows these general steps: