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Why Use Distilled Water?

Deep Cycle Battery Maintenance

By Abbie Randel - July 27, 2016

There are several important steps to properly maintaining your deep cycle batteries. You obviously know they are a financial investment, so why not take proper care of them to get the most life as possible. All steps of battery maintenance are critical and none of them should be over looked. One of the simplest choices to make is using distilled water to fill your batteries.

The electrolyte in a flooded deep cycle battery is a solution of acid and water. Using distilled or deionized water is recommend because it is free from additional minerals you would find in water such as regular tap water. Adding chemicals and minerals can significantly decrease the life of batteries. Distilled water should be the only things you ever replenish in your deep cycle batteries. Never add additional acid or electrolyte solution, this can also diminish the battery life. Distilled water can be purchased at any grocery store and is very inexpensive. Here at Colorado Golf & Turf, we offer free distilled water - just bring your own container!  A clean squeezable sports water bottle works great or battery fill bottles can be purchased at a local auto parts store, or right here in our parts department.

Here are a few additional tips on battery maintenance.
1. Clean your Battery First
  • Alaways wear safety glasses and rubber gloves when working with batteries
  • Make sure the battery caps are on tightly
  • Use a solution of baking soda and water (1 cup baking soda per gallon of water)
  • Rinse solution off of battery terminals - do not allow this solution to enter the battery
2. Check the Electrolyte Level of Each Battery (every one to two weeks)
  • Batteries should always be filled AFTER a full charge, UNLESS they are 'dry' and the plates are exposed.  In that case, fill with just enough water to reach the top of the plates, this is considered the minimum level of water.
  • Once the batteries have a full charge, check and add water if needed
  • Only add water if necessary - the water level should be 1/8″ below the bottom of the fill well
.Fill the Batteries
  • Use only distilled water - for the reasons above.
  • Add water until the electrolyte level is 1/8″ below the bottom of the fill well
  • Do NOT overfill batteries. Overfilling batteries and then charging can cause the batteries to bubble over and spill the electrolyte solution. Not only is this messy, it can be harmful if this solution is not properly rinsed from the skin. 
4. Replace the Battery Caps
  • Clean up any spills around the battery cells
  • Be sure not to allow any additional debris to enter the battery
  • Replace the battery caps back onto the batteries


Battery Watering Systems or Single Point Watering Systems (SPWS) can also be purchased to simplify this process.  They are a series of tubes connected to each battery with a single pump which is placed into a container of distilled water and pumped into each battery simultaneously and will stop pumping when batteries are at the proper level above the plates.