Flooded or Wet Cell batteries are the most common and economical lead-acid chemistry. Flooded batteries have a liquid electrolyte solution (hence, “wet”), which requires maintenance after charging and discharging cycles. Most Flooded batteries will require regular maintenance of its electrolyte every 3-6 months. If a Flooded battery is accidentally overcharged, additional electrolytes can be added to the battery, making it more resistant to improper charging. However, Flooded batteries experience substantial reduction in battery life if discharged below 50-percent depth-of- discharge. Care must be taken to avoid coming in contact with the battery acid, and must be installed in the vertical position.

Enhanced Flooded Batteries are an economical battery used in micro-hybrid vehicles that are designed to withstand the cyclic demands of start-stop vehicles. EFB batteries are similar to Flooded batteries as it has a liquid electrolyte solution, but designed to handle two times higher cycling endurance and roughly a 16-precent increase in duty cycle. Despite its increased performance for start-stop applications, EFB batteries are charged similar to standard Flooded batteries, and installed in the vertical position.

Gel Cell batteries were developed to create a non-spillable version of a Flooded battery. Internally, they are similar, except that the antimony in the lead plates is replaced by calcium and its electrolyte is combined with fumed silica to produce an immobilized solution. Unlike Flooded batteries, Gel Cell batteries can be mounted in almost any position. They have less electrolyte evaporation, an increased cycle life, and more resistance to shock, vibration and acid stratification. Although Gel Cell batteries are still found commercially, they have limited application of use due because of advancements in Absorbent Glass Mat (AGM) batteries.

Absorbent Glass Mat (AGM) represent the latest technology of non-spillable batteries. Instead of using a gelling agent, AGM batteries uses a fiberglass-like separator that absorbs the electrolyte in place. As a result, AGM batteries performance better than Flooded and Gel Cell batteries because they have a low internal resistance (which allows it to deliver higher currents), charge up to five times faster, and cycle down to 80-percent depth-of-discharge. Like all Sealed Lead-Acid batteries, AGM batteries are sensitive to improper charging.

Advanced AGM, or AGM batteries are similar to traditional AGM batteries, but have even higher cycling endorse and lower internal resistance, making these types of batteries the ideal battery for micro-hybrid, start-stop vehicles.