Pro-Fill - Frequently Asked Questions

Watering intervals are dependent on the local climate, charging methods, application, and age of batteries. Flow-Rite recommends that new batteries be checked once a month and older batteries be checked weekly until you get a feel for your water consumption rate.

Typically for a heavy use application, we recommend watering a maximum of once per week, and for light use applications once per month. Generally it is best to water on Wednesdays for most applications. Specifically you should not water a battery that has been sitting for an extended period of time with no activity (non use or not on charge) such as a battery that has sat over the weekend. It is best to water a warm battery that has just been fully charged.

A typical installation will take an inexperienced person on average 1 minute per battery.


No.  Your Pro-Fill system is designed to be left on your batteries while your vehicle is in winter storage; however, the system will not be operational while it is frozen.
If you have vehicles that are taken out of service or put into storage for a period of 6 weeks or longer, your single point watering system will require seasonal maintenance.  No special steps need to be taken for winterization of the SPW system that is mounted on the batteries; however, the following steps need to be followed when bringing your vehicle back into service:
After the batteries have been fully charged / equalized, connect the system to its water supply for 3-5 seconds then disconnect regardless of whether or not the batteries are completely full.
Return the vehicle to its regular service.
Place the vehicle back into its regular watering schedule (waiting at least 1 week until next watering).


Operating Requirement of Pro-Fill SPW system:
Flow-Rate: 2-5 gallons per minute*
Pressure Range : 3-35 PSI (no flow, static)
Temp. Range: 32º - 150º F (0º - 65.5º C)

Water supply Operating Requirements:
Inlet Pressure Range 40-100 PSI (no flow, static)
Temp. Range 33º - 150º F (1 - 65.5º C)

All product specifications should be met for proper operation of your Flow-Rite SPW system.  Contact battery supplier or Flow-Rite Controls if you have any questions regarding product specifications or how to verify a water supply.

*Flow rate should be measured at the end of a purger (female / male coupler combination).

You can fill a total of four 12-volt batteries, or a total of eight 6-volt batteries or a total of six 8-volt batteries or any other combination of batteries up to 24 cells at one time.

No, Leaving a water supply connect to the your SPW system will cause the batteries to be over filled as well as permanent damage to the water supply.  Always disconnect after filling is completed.


  • Water After Charge - Electrolyte levels drop during discharge and rise during charge. In addition, charging generates heat, fluid expansion and explosive gases.  Watering a battery before charge (or with a low charge level) can lead to boil over resulting in potential damage of the watering system, battery and vehicle. 
  • Water must always be added after fully charging the battery.  If your battery charger has an equalize function it is best to add water after equalizing the battery.  Prior to charging, there must be sufficient water to cover the plates. If the battery has been discharged (partially or fully), the water level should still be above the plates.

Flow-Rite reccomends that batteries are watered on a dedicated schedule to ensure that all batteries get watered.