Why a 72V Pack Needs Automatic Watering
AWS-36 · 36 watering heads · 60L tank · 72V traction packs
Thirty-six cells in one string is a maintenance problem before it is a watering problem. Every cell loses water at a slightly different rate, and the ones at the warm end of the pack lose it fastest. Hand watering a string that long takes half an hour done properly, and the half hour is exactly what goes missing on a busy shift.
What Happens When Watering Is Deferred
The electrolyte level drops below the top of the plates. The exposed plate area stops taking part in the reaction, so capacity falls and the pack works the remaining plate harder. Charging a pack in that state raises the acid concentration in the unexposed volume, which accelerates the sulphation that eventually ends the battery's life. None of this is visible from the driver's seat; it shows up a year later as a pack that no longer lasts a shift.
How the AWS-36 Solves It
Each of the 36 heads replaces a vent cap and carries its own float valve. Water enters through the pipe run, fills the cells that need it, and each valve closes as its cell reaches level. When the last one closes, flow stops at the indicator. The 60L tank is sized for a string of this length, so a single fill covers the pack rather than needing a refill halfway.
The head has a lens on top. A technician walking the bay can see the state of the pack without opening anything, and that is the difference between a task that gets checked and one that gets assumed.
Materials and Construction
Plastic heads and pipe, with a filter at the indicator to keep grit out of 36 small valves. The T-pieces rotate, which allows a run that follows the interlink pattern instead of cutting across it. End plugs close both ends of the run, and the K10 coupling connects the tank.
AWS-36 Kit Content
| Watering heads (T-piece) | 36 pcs |
| Flow indicator with filter | 1 pc |
| 6mm pipe | 8 m |
| 10mm pipe | 10 m |
| End plugs / K10 coupling | 2 pcs / 1 pc |
| Water tank | 60 L |
The Float, and Why It Lasts
The float is the part that decides whether the system behaves in year three as it did in week one. Its material is chosen to survive electrolyte and the temperature swings of a charging room, and its geometry is set so the valve closes at the same level every time rather than drifting with wear. A float that sticks is the failure mode to watch for, and it announces itself as a head that keeps taking water after the rest have stopped.
Service Routine
Once a month: fill the tank, connect, watch the indicator stop, disconnect. Once a quarter: check the filter and the pipe ends for grit or cracking. Once a year: pull one head and confirm the float moves freely. That is the whole routine, and it is short enough to actually happen.
Ordering
The head count follows the cell count. A 72V lead acid traction pack is commonly 36 cells, which is the configuration the AWS-36 is built for; send the cell count and the tray layout if the pack differs, and the kit is assembled to match.
