Battery Maintenance

Battery Type

Lead acid batteries are generally classified according to their application and construction. Their primary application is automotive where the battery is used for lighting and starting. Another basic application of lead acid batteries is deep-cycle which is usually broken down into more specific application such as, RV, marine, golf cars and renewable energy.

The most popular construction types are VRLA batteries (Valve Regulated Lead Acid) and flooded batteries (wet). In the VRLA batteries, the electrolyte is suspended in a gel or a fiberglass-mat (AGM technology), which allows the batteries to be mounted in different positions. In the flooded types, the electrolyte represents a solution of sulfuric acid and water that can be spilled out if the battery is tipped over.

We highly recommend you to identify the type of battery that you are replacing before proceeding to the next stages of battery maintenance.


There are many tools that can help you in taking care of your batteries. Some of the equipment required for proper battery maintenance includes: wrench, voltmeter distilled water, hydrometer, baking soda, post cleaner, Vaseline, gloves, goggles etc.

CAUTION: You must always wear protective gloves, clothing, gloves and goggles when handling and charging your batteries, so that you don’t have direct contact with the electrolyte.

You should inspect your batteries on regular basis in order to detect and handle potential problems before they end up causing damage.

General Inspection Guidelines:

  • Examine the outer appearance of the battery. Inspect the container for cracks and make sure the top of the battery, the connections and the posts are clean and free of fluids, dirt and corrosion. In case your battery is dirty, please read the Cleaning section below and follow the step-by-step cleaning procedure. You should repair or replace any damaged batteries.
  • If you notice any fluids on or around the battery this might be an indication that electrolyte is leaching, spilling, or leaking out of it. Leaking batteries must be immediately repaired or replaced.
  • Examine all battery cables and their connections. Check them for loose or damaged parts. The cables of the battery should be intact. Frayed or broken cables can be extremely dangerous. If any of the cables looks suspicious we recommend you to replace it as soon as possible.

You should tighten all wiring connections to the proper specification. Make sure that there is good contact with the terminals of the battery. For VRLA batteries:

  • Button 90 to 100 in-lbs
  • LT 100-120 in-lbs

CAUTION: Do not over tighten terminals. Doing so can result in post breakage, post meltdown, or fire.


Batteries have a tendency to attract dirt, dust and grime. Keeping them clean will enable you to spot trouble signs if they appear and help you prevent future problems from happening.

  • Always check whether all vent caps are tightly in place.
  • Clean the battery top with a cloth or brush and a solution of baking soda and water. You should make sure that no cleaning solution, or other foreign matter goes inside of the battery.
  • Rinse the battery well with water and dry it up with a clean cloth.
  • Clean battery terminals and the inside of cable clamps with the use of a post and clamp cleaner. Clean terminals would typically have a bright metallic shine.
  • The next step is to reconnect the clamps to the terminals and coat them thinly with petroleum jelly (Vaseline) in order to protect the battery from corrosion.
  • The area around the batteries must always be kept clean and dry.


When placing your battery into storage, please consider the following recommendations to make sure that the battery stays healthy and ready for use.

NOTE: Storing, operating or charging batteries on concrete surfaces is OK.

Things to avoid:

  • Avoid handling your batteries in locations where freezing temperatures are expected. Freezing could lead to irreversible damage to the battery's plates and its container. A good way to prevent a battery from freezing is to keep it at a high level of charge.
  • Keep your battery away from heat sources, such as space heaters and radiators. Temperatures exceeding 80° F would accelerate the battery's self-discharge characteristics.

Guidelines for storage procedure:

  • Before placing your battery into storage make sure that it’s completely charged.
  • Batteries should be stored in a cool and dry location, where they can be well protected from the elements.
  • While you are storing your battery, monitor their voltage regularly. If it shows a charge of 70% or less, we recommend you to give it a boost charge.
  • Before re-activating your battery you should make sure that it is fully charged.

Charger Selection

Many deep-cycle applications available on the market have some sort of charging system installed within them for the purpose of battery charging. And yet there are still some systems with deep-cycle batteries that would require a separate charger.

Nowadays, there is a wide range of chargers available on the market. Chargers are typically rated by their start rate, which represents the initial rate in amperes that the charger would supply at the beginning of the charge cycle. While you are choosing a charger you should bear in mind that the charge rate of the charger should be between 10% and 13% of the battery's 20-hour AH capacity. For instance, a battery with a 20-hour capacity rating of 225 AH would require a charger with an approximate rating between 23 and 30 amps (in case of multiple battery charging use the AH rating of the entire bank to calculate the charger rating required).

Note: You can use chargers with lower ratings but in this case the charging time would be increased.


Proper battery charging requires administering the correct amount of current at the right voltage. Most charging equipment today is regulating these values automatically. Yet some chargers allow the users to set these values by themselves. Both manual and automatic equipment can present some difficulties in charging. For proper charging, you should follow the instructions that came with your charging equipment.

Things to remember:

  • Get familiar with the instructions from the charger manufacturer and follow them strictly.
  • You should make sure that your battery is charged after each period of use.
  • Lead-acid batteries would not develop a memory, so you don’t need to discharge them completely before recharging them.
  • Charge only in well-ventilated areas. Keep charging batteries away from sparks or flames.
  • Make certain the charger voltage settings are correct.
  • Check the electrolyte level of your battery.
  • Before charging the battery check all vent caps carefully and make sure that they are tightened properly.
  • Do not undercharge or overcharge the batteries.
  • You must never charge a frozen battery.
  • Avoid charging at temperatures exceeding 120°F.


Discharging batteries is entirely a function that depends on the type of application. When you are attempting to discharge a battery please keep in mind the fallowing recommendations:

  • Shallow discharges would prolong the life of the battery.
  • 50% (or less) discharges are recommended.
  • 80% discharge is the maximum safe discharge.
  • Many experts recommend operating batteries only between 50% and 85% of full charge range. When using this practice you must provide your battery with a periodic equalization charge.
  • Batteries must not be left deeply discharged not even for a short period of time.
  • Lead acid batteries do not develop a memory so you don’t need to discharge them completely before recharging them.
  • In case you notice that your battery charges up but it is unable to support a load this might be an indication that battery is bad and it should be tested.
  • Batteries should be charged after each use.