Home > Electrical > Battery Watering Systems >

Flow-Rite BG-U48V-8J Pro-Fill Universal 48V Battery Watering System for 8x 6V or 4x 12V Batteries

Flow-Rite BG-U48V-8J Pro-Fill Universal 48V Battery Watering System with automatic shut-off valves and flex manifold tubing for 8x 6V or 4x 12V batteries
Flow-Rite Pro-Fill Universal 48V Battery Watering System
 
: $146.08
Part Number: BG-U48V-8J
Manufacturer: Flow-Rite

Quantity in Stock :8

Free Shipping
Availability: In Stock
Qty:

 
Flow-Rite 48V System 8x 6V or 4x 12V

Flow-Rite BG-U48V-8J Pro-Fill Universal 48V Battery Watering System

Stop checking and filling each cell individually. The Pro-Fill system replaces your existing vent caps with automatic shut-off valves interconnected by flexible manifold tubing, so you can water an entire 48V battery bank in a single step -- every cell filled to the correct level, every time.

One Connection. Every Cell. Done.

Deep-cycle flooded lead-acid batteries need regular watering to prevent premature failure -- but opening each cap, checking levels, and filling individually is time-consuming and easy to get wrong. Overfilling dilutes electrolyte and corrodes battery tops; underfilling damages plates. The Flow-Rite Pro-Fill system eliminates both problems.

The BG-U48V-8J is engineered for a standard 48V bank: eight 6-volt batteries wired in series, or four 12-volt batteries wired in series. A single water supply connection feeds all cells through the manifold tubing. Each automatic shut-off valve stops flow the moment the electrolyte reaches the correct fill level -- no float, no guessing, no overflow.

Automatic Shut-Off

Pressure-actuated valves stop water flow precisely at the correct cell level -- no timer, no manual checking required.

128 Flex Manifolds

Pre-cut flexible tubing interconnects all valves so the entire bank fills from one inlet connection.

Universal Fitment

Valves replace standard vent caps on 6V and 12V flooded deep-cycle cells including golf cart, RV, and marine batteries.

48V Bank Ready

Pre-configured for 8x 6V or 4x 12V batteries -- no counting tubing lengths or sourcing additional valves.

How the Pro-Fill System Works

Each automatic shut-off valve threads into the existing vent cap opening on a battery cell. The valves are then linked together with the included flexible manifold tubing. When you connect a water source -- gravity-fed jug, hand pump, or pressurized line -- water flows through the manifold into each cell simultaneously. As the electrolyte rises to the proper level in each cell, the valve shuts off automatically. When all cells are full, back-pressure stops flow at the supply end so you know the job is complete.

The design keeps water off the battery tops, reduces corrosion on terminals and trays, and dramatically cuts the time required for routine watering maintenance.

Why Regular Watering Matters

  • Exposed plates sulfate rapidly, permanently reducing capacity and lifespan.
  • Overfilling causes acid overflow onto battery trays and cables, accelerating corrosion.
  • Consistent electrolyte levels keep all cells balanced, extending pack life and maintaining full capacity.
  • Automatic shut-off valves remove the margin for human error on both ends -- too high and too low.

Designed for RV, Golf Cart, and Industrial Deep-Cycle Banks

The BG-U48V-8J is the correct kit for the most common 48V configurations: an 8-battery string of 6V golf cart cells (Trojan T-105, T-125, T-145 style), or a 4-battery string of 12V deep-cycle cells. This covers the typical house battery bank in Class A and Class C motorhomes, fifth-wheel coaches, and dedicated solar storage rigs running 48V inverter systems.

Because the valves replace standard vent caps, no drilling or permanent modification to the batteries or tray is required. The system is removable and transferable to a new battery set when you replace the bank.

Compatible Battery Types

  • Flooded lead-acid deep-cycle 6V batteries -- golf cart style (GC2, GC8, T-105, T-125 families)
  • Flooded lead-acid deep-cycle 12V batteries with standard vent cap openings
  • Not compatible with sealed (AGM, gel, or lithium) batteries -- those require no watering
  • Check that your battery vent cap thread matches the Pro-Fill valve thread (standard SAE vent cap thread on most U.S. deep-cycle batteries)

What Is Included in the Box

  • Automatic shut-off fill valves -- quantity matched to the cell count for the 48V configuration
  • 128 flex manifold tubing segments for interconnecting all valves
  • Single inlet fitting for connecting your water supply
  • Hardware and tubing connectors for complete installation

A separate water supply (hand pump, gravity jug, or Flow-Rite pump) is not included. Flow-Rite offers compatible hand pumps and pump kits sold separately.

Maintenance and Installation Tips

  • Always water batteries after a full charge cycle, not before -- charging expands electrolyte and can cause overfill if topped up beforehand.
  • Flush the manifold tubing with clean distilled or deionized water before first use to clear any manufacturing residue.
  • Use only distilled or deionized water; tap water introduces minerals that degrade electrolyte over time.
  • Inspect tubing connections periodically for secure seating, especially after vibration-heavy trips.
  • Route tubing away from sharp edges, heat sources, and moving components in the battery compartment.

Product Identification

ManufacturerFlow-Rite Controls
Part NumberBG-U48V-8J
Product LinePro-Fill Universal Battery Watering System
System Voltage48V bank

System Configuration

Batteries Covered8x 6V deep-cycle, or 4x 12V deep-cycle
Manifold Tubing128 flex manifold segments included
Fill MethodSingle-point inlet; fills all cells simultaneously
Valve TypeAutomatic pressure shut-off (no float mechanism)
Water Supply RequiredGravity, hand pump, or low-pressure line (sold separately)

Battery Compatibility

Cell ChemistryFlooded lead-acid (wet cell) only
Battery Format6V deep-cycle (golf cart style) and 12V deep-cycle
Not Compatible WithAGM, gel, sealed VRLA, or lithium batteries
Vent Cap FitStandard SAE vent cap thread openings

Typical Application

RV UseClass A, B+, C motorhomes; fifth wheels with 48V house bank
Golf Cart Use48V golf cart battery packs (8x 6V configuration)
Solar/Off-Grid48V deep-cycle storage arrays
IndustrialFloor scrubbers, scissor lifts, and other 48V flooded-cell equipment

Physical and Installation

Valve InstallationThreaded replacement for existing vent caps -- no drilling
Tubing MaterialFlexible polymer manifold tubing
Permanent ModificationNone required; system is removable

Important Information -- Read Before Installing

  • Flooded lead-acid batteries only. Do not install on AGM, gel, sealed VRLA, or any lithium battery. These battery types are sealed and require no watering; installing fill valves will damage them.
  • Water AFTER charging, not before. Electrolyte expands during charge. Adding water to discharged or partially charged cells risks overflow and acid spills when the bank is later charged.
  • Use distilled or deionized water only. Tap water minerals contaminate electrolyte and shorten battery life.
  • Water supply not included. A hand pump, gravity jug, or external pump is required to use this system and must be purchased separately.
  • Verify vent cap thread compatibility before ordering. Most U.S.-made deep-cycle 6V and 12V batteries use a standard SAE vent opening, but confirm with your battery manufacturer if unsure.
  • Battery acid hazard. Wear eye protection and acid-resistant gloves when working near open flooded-cell batteries. Hydrogen gas is produced during charging -- ensure adequate ventilation before servicing.
  • This kit is pre-configured for 48V banks (8x 6V or 4x 12V). For 6V, 12V, 24V, or 36V bank configurations, different Flow-Rite kit part numbers are required.
Vehicle Make Vehicle Model Vehicle Year Battery Voltage # Of Batteries Battery Make & Model Part Number
EXV2 or EXV4 2003+ 8
U.S. Battery BG-U72V-6G
EXV2 or EXV4 2003+ 8
Trojan BG-U72V-5G
Club Car Precedent 2007+ 8 6 Crown BG-U48V-6G
Club Car Precedent Other 12 4 U.S. Battery BG-U48V-1A
Club Car Precedent Other 12 4 Trojan Plus Series BG-U48V-8J
Club Car DS 2007+ 12 4 U.S. Battery BG-U48V-1A
Club Car Limo 2007+ 8 6 Trojan BG-U48V-5G
Club Car DS 2007+ 12 4 Trojan BG-U48V-1A
Club Car Limo 2007+ 8 6 Crown BG-U48V-6G
Club Car Precedent Other 12 4 Trojan BG-U48V-1A
Club Car DS 2007+ 8 6 Trojan BG-U48V-5G
Club Car DS 2007+ 8 6 U.S. Battery BG-U48V-6G
Club Car Limo 2007+ 8 6 U.S. Battery BG-U48V-6G
Club Car DS 2007+ 8 6 Crown BG-U48V-6G
Club Car Precedent 2007+ 12 4 U.S. Battery BG-U48V-1A
Club Car DS Other 8 6 U.S. Battery BG-U48V-6G
Club Car Precedent 2007+ 12 4 Trojan BG-U48V-1A
Club Car DS Other 8 6 Crown BG-U48V-6G
Club Car Precedent 2007+ 8 6 U.S. Battery BG-U48V-6G
Club Car DS Other 8 6 Trojan BG-U48V-5G
Club Car Precedent 2007+ 8 6 Trojan BG-U48V-5G
Duffy Cat-16 Other 6 8 Trojan BG-Duffy-01
Duffy Cat-16 Other 6 8 U.S. Battery BG-Duffy-01
Duffy Cat-16 Other 6 4 Crown BG-Duffy-01
E-Z-GO RXV 2008+ 12 4 Trojan Plus Series BG-U48V-8J
John Deere Gator Other 6 8 U.S. Battery BG-U48V-1G
John Deere Gator Other 6 8 Trojan BG-U48V-1G
John Deere Gator Other 6 8 Crown BG-U48V-1G
Par Car Eagle Other 6 8 Crown BG-U48V-1G
Par Car Eagle Other 6 8 U.S. Battery BG-U48V-1G
Par Car Eagle Other 6 8 Trojan BG-U48V-1G
Par Car Summit Other 6 8 U.S. Battery BG-U48V-1G
Par Car Summit Other 6 8 Trojan BG-U48V-1G
Par Car Other 6 8 Crown BG-U48V-1G
Polaris Ranger EV Other 12 8 U.S. Battery BG-U96V-1A-2C
Polaris Ranger EV Other 12 8 Trojan BG-U96V-1A-2C
Polaris Ranger EV Other 12 8 Crown BG-U96V-1A-2C
Sanyo Other Other 12 6 Crown BG-U72V-1A
Sanyo Other Other 12 6 Trojan BG-U72V-1A
Sanyo Other Other 12 6 U.S. Battery BG-U72V-1A
Tennant T7 Scrubber Other 6 4 Trojan BG-U24V-1G
Tomberlin Proline Other 8 6 Trojan BG-U48V-5G
Tomberlin Proline Other 8 6 U.S. Battery BG-U48V-6G
Tomberlin Proline Other 8 6 Crown BG-U48V-6G
Tomberlin E-MERGE Other 8 6 Trojan BG-U48V-5G
Tomberlin E-MERGE Other 8 6 U.S. Battery BG-U48V-6G
Tomberlin E-MERGE Other 8 6 Crown BG-U48V-6G
Western Other Other 6
U.S. Battery BG-U42V-3
Western Other Other 6
Trojan BG-U24V-3
Western Other Other 6
Crown BG-U42V-3
Yamaha G19 1996+ 8 6 U.S. Battery BG-U48V-6G
Yamaha G19 1996+ 8 6 Trojan BG-U48V-5G
Yamaha G23 Other 6 8 U.S. Battery BG-U48V-1G
Yamaha G23 Other 6 8 Trojan BG-U48V-1G
Yamaha G23 Other 6 8 Crown BG-U48V-1G
Yamaha Drive 2007+ 12 4 U.S. Battery BG-U48V-1A
Yamaha Drive 2007+ 12 4 Trojan BG-U48V-1A
Zone Other Other 6 8 U.S. Battery BG-U48V-1G
Zone Other Other 6 8 Trojan BG-U48V-1G
Zone Other Other 6 8 Crown BG-U48V-1G

ACCESSORIES
Flow-Rite RV-2020 Battery Filler Hand Pump for Pro-Fill RV, Qwik-Fill & Millennium SPW Systems Flow-Rite BA-554 Mini Pump Tank - 5 Gallon Flow-Rite EA-006 Eagle Eye Deep Cycle Battery Water Level Sensor Kit for Pro-Fill Systems
: $36.74

Add
: $44.78

Add
: $75.54

Add
Flow-Rite RV-2020 Battery Filler Hand Pump with squeeze bulb, quick disconnect fitting, and intake filter for RV battery watering systems Flow-Rite BA-554 Mini Pump Tank - 5 Gallon Flow-Rite EA-006 Eagle Eye deep cycle battery water level sensor kit with LED indicators for Pro-Fill single-point watering systems


Browse for more RV Accessories in the same category as this item:

Electrical > Battery Watering Systems
Electrical


$103.49