A gel cell is a lead-acid battery which has a thixotropic gelled elctrolyte in stead of a liquid electrolyte. As result, the battery in non-spillable and can be operated in virtually any position. However, operation upside down is not recommended. Gel batteries typically have up to three times the cycle life of a wet cell antimony alloy deep cycle battery.

Both are recombinant batteries; both are sealed valve regulated.

The major difference is that the "starved" or"absorbed electrolyte" battery contains an amount of liquid electrolyte added at the factory that soaks into the special separators. Therefore, it is non-spillable since all the electrolyte is trapped in the sponge-like separator material. There is no "free" electrolyte to spill if tipped or punctured.

Because of this "acid-starved" condition, this type of battery does not normally perform well in heavy, deep discharge applications. The gel cell has more electrolyte available, therefore it is better suited to deep discharge applications and can accept occational overcharging.

Wet cells do not have special pressurized sealing vents, as they do not work on the recombination principle. They contain liquid electrolyte that can cause corrosion and spill if tipped or punctured. Therefore, they are not air transportable without special containers. They can not be shipped via UPS or Parcel Post or used near sensitive electronic equipment. Installation has to be upright to prevent spillage of the liquid electrolyte.

Wet cells can lose capacity and become permanently damaged if:

- left in a discharged state for any length of time. This is especially true of antimony and hybrid types.

- continually overcharged, due to active material shedding. This includes specially designed deep cycle wet cells, but is especially true for antimony types.

Gel Battery Advantages
• Totally maintenance free
• Air transportable
• No corrosion
• Spill proof/leak proof
• Installs upright or on its side
• Superior deep cycle life
• Very low to no gassing (unless overcharged)
• Compatible with sensitive electronic equipment
• Superior shelf life
• Rugged and vibration resistant
• Very safe at sea with no chlorine gas in bulge (due to sulfuric acid and salt water mixing)
• Will not freeze to -20°F
• Lowest cost per month (cost / months of life)
• Lowest cost per cycle (cost/ life cycles)

Gel Battery Disadvantages
• Higher initial cost
• Heavier weight
• Water can not be replaced if continually overcharged
• Automatic temperature sensing, voltage- regulated chargers must be used
• Charge voltage must be limited to extend life
(13.8 to 14.1 volts maximum at 68°F)

Absorbed Electrolyte Advantage
• Totally maintenance free
• Spill proof/ leak proof
• No corrosion
• Installs upright or on its side
• Lower initial cost than gel batteries
• Compatible with sensitive electronic equipment
• Very low to no gassing (unless overcharged)
• Excellent for starting and stationary applications
• Will accept a higher charging voltage than gel batteries

Absorbed Electrolyte Disadvantages
• Shorter life cycle than gel in deep cycle applications
• Automatic temperature sensing, voltage regulated chargers must be used
• Water can not be replaced if continually overcharged
• Charge voltage must be limited to 14.4 to 14.6 volts maximum at 68°F