Battery Types
As long as the battery starts the car we just ignore it. When it finally stops working we think that buying a bigger, and better, battery can solve the problem. How about just taking care of the battery you currently have in the car? Novel as this idea might be it’s worth some consideration.
First, what type of battery do you have in your car? There are three basic types of batteries.
Wet Cell: This is the most common lead-acid battery. They offer the greatest array of size and design. While some still have caps that allow you to replenish the electrolyte the battery vents while charging many are now “maintenance-free” with no access to the cells.
Each cell has a grid of lead plates along with a liquid electrolyte that’s based on sulphuric acid. Since the grid is only supported at the edges, flooded lead-acid batteries are structurally the weakest batteries. Because the container is not always sealed you have to be careful to make sure that the electrolyte doesn’t come in contact with your skin, clothes or painted surfaces.
Gel Cell: Gel cell batteries use a thickening agent such as fumed silica to immobilize the electrolyte. This silica additive causes the electrolyte to set up or stiffen. If the battery container cracks the cell will continue to function because this thickening agent prevents any movement of the electrolyte.
Because gel cell batteries are sealed and cannot be re-filled with electrolyte it’s critical to control the rate of charge. Gel cell batteries use slightly lower charging voltages than flooded cells which means the set-points for charging equipment have to be adjusted.
Absorbed Glass Mat (AGM) Battery: The absorbed glass mat battery has the electrolyte absorbed in a fiberglass mat. These are the latest step in the evolution of lead-acid batteries. The physical bond between the separator fibers, the lead plates, and the container make AGMs not only spill-proof but also the most vibration and impact resistant lead-acid batteries available today.
Daryl Brock at Optima points out that an AGM battery won’t necessarily leak if the container is damaged since the acid is held in suspension by the glass mat. That means there really isn’t any acid to spill out of the case. Basically, an AGM can do anything a Gel-cell can, only better. Because they’re sealed charging has to be carefully controlled or they can be ruined in short order.
