Complete detailed guide covering battery maintenance procedures


Period Inspection:
Recommended Equipment:

  • Spanner
  • Distilled water
  • Voltmeter
  • Hydrometer
  • Baking soda
  • Vaseline
  • Goggles & gloves

CAUTION: Always wear protective clothing, gloves, and goggles when working with batteries
Batteries should be inspected on a regular basis – at least at the start and end of season.


1. Examine the outside appearance of the battery.

  • Look for cracks in the container.
  • The top of the battery, posts, and connections should be clean, free of dirt, fluids, and corrosion.
  • Repair or replace any damaged batteries.

2. Any fluids on or around the battery may be an indication that electrolyte is spilling or leaking out.

  • Leaking batteries must be repaired or replaced.

3. Check all battery cables and their connections.

  • Look closely for loose or damaged terminals.
  • Battery cables should be in good condition – Bad connection can impede current flow and generate a lot of heat.
  • Replace any cable that looks suspicious.

4. Make sure all connections are tight but do not over tighten. Make sure there is good contact with the terminals.

Visual inspection alone is not sufficient to determine the overall health of the battery. Both open-circuit voltage and specific gravity readings give a good indication of the battery’s state of charge.
Routine checks will not only show the state of charge but also help spot signs of improper care, such as undercharging and possibly even locate a bad or weak battery.

Specific Gravity Test – (Flooded batteries only)

  • Do not add water at this time.
  • Fill and drain the hydrometer 2 to 4 times before pulling out a sample.
  • There should be enough sample electrolyte in the hydrometer to completely support the float.
  • Take a reading, record it, and return the electrolyte back to the cell.
  • To check another cell, repeat the 3 steps above.
  • Check all cells in the battery.
  • Replace the vent caps and wipe off any electrolyte that might have been spilled.
  • Compare the readings.
  • Check the state of charge using Table below

The readings should be 1.270 or above. If any specific gravity readings register low, then follow the steps below.

  • Check and record voltage level(s).
  • Put battery(s) on a complete charge.
  • Take specific gravity readings again.

If any specific gravity readings still register low then follow the steps below.

  • Check voltage level(s).
  • Perform equalization charge.
  • Take specific gravity readings again.

If any specific gravity reading still reads low one or more of the following conditions may exist:

  • The battery is old and approaching the end of its life.
  • The battery was left in a discharged state too long.
  • Electrolyte was lost due to spillage or overflow.
  • A weak or bad cell is developing.
  • Too much water has been added.

Open-Circuit Voltage Test
For accurate voltage readings, batteries must remain idle (no charging, no discharging) for at least 8hrs, preferably 24 hrs.

  • Disconnect all loads from the batteries.
  • Measure the voltage using a DC voltmeter.
  • Check the state of charge
  • Charge the battery if it registers

If battery registers below the Table 1 values, the following conditions may exist:

  • The battery was left in a state of discharge too long.
  • The battery has a bad cell.

Battery State of charge:

Topping Up
– (Flooded batteries only)
Flooded batteries need water. More importantly, there is a correct time to water your battery!
Water should always be added after fully charging the battery. Prior to charging, there should be enough water to cover the plates. If the battery has been discharged (partially or fully), the water level should also be above the plates. Keeping the water at the correct level after a full charge will prevent having to worry about the water level at a different state of charge.
Important things to remember:

  • Do not let the plates get exposed to air. This will damage (corrode) the plates.
  • Do not fill the water level in the filling well to the cap.
  • This most likely will cause the battery to overflow acid, consequently losing capacity and causing corrosion.
  • Do not use water with a high mineral content. Use distilled or deionized water only.

CAUTION: The electrolyte is a solution of acid and water so skin contact should be avoided.
Topping up procedure:

  • Open the vent caps and look inside the fill wells.
  • Check electrolyte level – the minimum level is at the top of the plates.
  • If necessary add just enough water to cover the plates at this time.
  • Put batteries on a complete charge before adding any additional water.
  • Once charging is completed, open the vent caps and look inside the fill wells.
  • Add water until the electrolyte level is 5-10mm below the bottom of the fill well. There is often a plastic marker
  • Clean, replace, and tighten all vent caps.

WARNING: Never add acid to a battery.
Batteries seem to attract dust, dirt, and grime. Keeping them clean will help one spot trouble signs if they appear and avoid problems associated with grime.

  • Check that all vent caps are tightly in place.
  • Clean the battery top with a damp cloth and a solution of baking soda and water.

When cleaning, do not allow any cleaning solution, or other foreign matter to get inside the battery.

  • Rinse with water and dry with a clean cloth.
  • Clean battery terminals and the inside of cable clamps using a post and clamp cleaner.
  • Clean terminals will have a bright metallic shine.
  • Reconnect the clamps to the terminals and then apply a thin coat of petroleum jelly to prevent corrosion.
  • Keep the area around batteries clean and dry.