How to maintain lead-acid batteries

The fluid in a lead-acid battery, the electrolyte, consists of a mixture of sulphuric acid and water. When the battery is charged, the electrolyte heats up. This causes some of the water to evaporate through electrolysis, whereby the water breaks down into hydrogen and oxygen gases that then dissipate. Consequently, the electrolyte level in the battery decreases over time. If the level gets too low, the sulphuric acid becomes more concentrated, and the plates in the battery cells become exposed and damaged. This is why the electrolyte needs to be replaced regularly. Here are some things to take into account:

1. Check the water level

   Although you can manually check the battery to determine when to add water, there are easier and less time-consuming alternatives. Indicators, for example, can be mounted behind the battery plug and notify you when the battery needs to be topped up. 

2. Only use distilled water

   Never fill a battery with tap water, as this will damage it. Instead, use distilled water, also known as deionised or demineralised water, which has been filtered to remove the metals and minerals that can interfere with the battery’s processes.

3. Install an automatic battery water filler system

   The amount of distilled water required to top up a battery can vary, which is why using a battery water filler system is recommended. This system utilises filler caps with floats that are connected to each other via water hoses, preventing the battery from overfilling. All you need to do is run distilled water into the hose; the filling system takes care of the rest.

4. Beware when charging

   Before charging the battery, always ensure that the electrolyte covers the battery plates. If they are covered, charge the battery and then top it up as necessary. This is because the electrolyte expands during charging and is more likely to overflow if topped up beforehand.

Leakage currents caused by battery acid, dirt and dust can make a battery discharge itself and become unbalanced. Therefore, it is essential to keep batteries clean and free from debris. Various products are available to help with cleaning batteries, such as battery steam cleaners.