Swollen batteries are an indication that they have been overcharged.
The two most common causes are improper maintenance, leading to a dropped cell, and solar problems.
Each cell of a battery is usually around 2.1-2.2 volts when rested and new. This deteriorates with age and wear.
When a battery sulphates due to being at a frequent low state of charge or severely deep discharge, it can cause a cell to fail. This leaves the battery essentially becoming a 10.5 or 10.6 volt battery. This leads to a regular charger running to 14.4 volts overcharging the remaining 5 cells.
This is not normally a warrantable condition.
It can also be a failure of the battery that causes a cell to drop. This can be determined by the battery manufacturers who can discern between sulfation and failure.
Shorts on solar line
A short on the solar line can back-feed through the system and overcharge the battery. You will usually see a voltage around 16-17v when this occurs. To identify the issue, take the following steps:
- Remove positive and negative solar connections from the solar regulator.
- Check all cables, one at a time, for continuity against a ground source. This can be a battery negative, though it's preferable to go to a ground connection or earth pin on a GPO, if not connected to mains.
If there is continuity on any cable, positive or negative, there is a short to ground on that solar line and this needs to be located and rectified. This needs to be documented and the source of the problem recorded with photos if possible.
It will likely be covered under warranty as a manufacturing issue provided no additions have been made that caused the problem.
As always, if you have any concerns, contact us by calling on 03 9303 7033, emailing us at firstname.lastname@example.org or using the "help" button on the bottom-right of your screen.