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Battery Watering Guidelines


  • Lead-acid batteries used in cyclical discharge applications such as forklifts, personnel carriers, wire-guided vehicles and golf carts require that it is ‘topped-off’ with distilled water. On average, watering intervals are required weekly.
  • Automatic or ‘single-point’ watering systems reduce the labor time required to water the batteries as opposed to manually providing maintenance to each individual cell. When used properly and maintained effectively, single point watering systems can provide significant cost savings.
  • Underwatering reduces battery power and can cause heating that reduces the life of the battery. Overwatering causes acid exposure (boil-overs), creating external shorts, corrosion, and electrolyte imbalance, resulting in reduced battery power.
  • Proper battery maintenance ensures maximum performance and life. Training to perform correct watering is simple and only requires an individual to use all necessary precautions and PPE. The labor time to perform regular maintenance varies per battery.

Watering Schedule

Low electrolyte level in a battery cell can cause the plates to oxidize and shorten the life of the cell and the battery. To prevent electrolyte levels from falling too low, water should be added often enough to keep the electrolyte level above the perforated separator protectors.

Ideally, a watering schedule should be adopted and strictly followed. As a best practice, water should be added to all of the batteries assigned to each charging area on a regular time schedule. The electrolyte levels should also be spot checked periodically to determine if the proper levels are being maintained. Determining a reasonable and proper battery watering time schedule is dependent on how widely the following three factors vary:

Older batteries and those in poor condition will consume water more rapidly than newer batteries and those that have been properly maintained. Additionally, some cell types have a greater water storage capacity than others. 

Depending on these variable factors, the batteries assigned to a specific charging area might require watering at different intervals. The frequency of watering is best determined by firsthand experience. For example: if some batteries have low electrolyte levels when a weekly watering schedule is followed, change the schedule to twice a week.


Watering Frequency

In single shift applications operating under moderate ambient temperatures, lead-acid batteries require ‘topping-up’ of cells after 5-6 discharge/charge periods. This ensures that no part of the element is exposed to Oxygen as plate areas that are not immersed entirely by electrolyte will not produce energy. Operating a lead-acid battery with low electrolyte levels results in power loss and the permanent loss of capacity to produce energy. Batteries operating with appropriate electrolyte levels will not experience ‘boil-overs’.


  • Boil-overs’ occur when a battery has been over watered and the electrolyte levels are too high. This results in the loss of energy producing potential from the battery. Most ‘boil-over’ events require that the electrolyte density is restored by a battery expert.
  • Opportunity charging and fast charging operations can expect a higher frequency of maintenance. Batteries are charged and recharged multiple times a day, some as much as 1.6 times normal operation.
  • In the case of 36, 48, and 80V batteries, centrally located cells will generally require additional water demands than perimeter cells. This can often lead to over watering of the battery. Ideally, electronic battery fluid level indicators, or blinky, should be installed on centrally located cells.
  • Single-point waterings systems eliminate the labor time required to maintain batteries effectively. Batteries can easily be topped off with water without physically removing and manually adding water to each individual cell. This prevents the need for a battery to be extracted from the vehicle, often a tedious and time consuming task. 

    Single-point watering systems require that batteries are watered on a consistent schedule. Overwatering can occur if watering is not controlled.