Gell Cells versus AGM
These type of batteries should never be referred to as “sealed” or “maintenance-free” batteries because they are neither.
- They are not sealed because they have a pressure-relief valve which will open if the battery’s internal pressure rises above a preset safe recombinant level.
- They are not maintenance-free. The IEEE requires them to have as much periodic maintenance as Vented Lead-Acid (VLA) flooded batteries.