Maintenance and small repairs of a deep cycle lead acid battery

Maintenance and small repairs of a deep cycle lead acid battery

We will be looking at maintenance and small repairs on a deep cycle lead acid battery. Commonly these are used for forklifts or OffGrid power systems. We are talking about big battery blocks, not the ones used for common cars.
To ensure optimal lifetime of your deep cycle lead-acid batteries you should do maintenance at least once every half year to a year.

On the image you can see here there is quite a bunch of sulfation that formed. Initially sulfation will be green but, over time it can take all sorts of colours. While it is still green it usually is rather easy to remove, once it turned brown’ish to black its becomes very solid. As an idea of size, this battery here is my main block, it has 1250 Ah at 24 volts.

For safety, before we start doing anything on the battery we will be disconnecting all the connections. First by turning the fuses from the inverter and all the solar charge controllers off. Next we physically disconnect the battery from the system by separating the connection plugs. For this system each inverter and charge controller has its own connection plug.

If you are interested in how this complete OffGrid power system works check out the Project Link.

After removing the connections to the battery, unscrew each of the batteries cell connections, and remove any sulfation you encounter around the pole.

This can require quite some force. It is recommended to wear safety googles and a dust mask for this.

After cleaning all the connections of sulfation, make sure to apply batteryfat to all the connections before screwing them back on.
This helps to protect against moisture and future sulfation or oxidisation.

Some 2-3 hours of work later, your battery should look something like this. No visible dirt, dust or particles of sulfation leftover. No sulfation on the connections and a fresh layer of batteryfat.

Next we will be checking the waterlevel of the battery.
Each battery cell has the connection for the distilled water in the middle.
when you look closely you can see there is a small window build in. Under that is a swimmer that shows the water level of the cell. This will indicate a need for refill.
Use only distilled water for this, do not use normal tab water as it will damage the battery!
After refilling the battery reconnect the system plugs and we are done.