AGM and Gel Batteries: What’s common between them and what are the differences

Posted by on 29th May 2019

AGM and Gel Batteries: What's Common Between Them And What Are The Differences

There are several subcategories of lead acid batteries and we will now take a closer look at GEL cell and AGM batteries to compare their characteristics.

AGM and Gel Batteries

AGM Batteries:

The Absorbent Glass Mat (AGM) refers to a fine fiberglass mat that is capable of absorbing sulfuric acid, making batteries spill proof. The AGM construction allows the electrolyte to be suspended in close proximity with the plate’s active material. In theory, this enhances both the discharge and recharge efficiency. AGM batteries contain just enough liquid to keep the mat wet with the electrolyte and if the battery is broken no free liquid is available to leak out. Actually, the AGM batteries are a variant of Sealed VRLA batteries, with a more advanced design.

AGM Batteries outsell Gel ones by at least a 100 to 1 ratio. Notably, AGM is preferred when a high burst of amps may be required. For the most cases, recharge can be accomplished by using a good, high-quality standard battery charger or engine alternator. The life expectancy; measured as cycle life or years remains steady and excellent in most AGM batteries if the batteries are not discharged more than 60% between recharges. In addition, all of the AGM batteries we sell offer excellent 80%+ deep cycle abilities.

GEL Batteries:

The Gel cell is similar to the AGM style because the electrolyte is suspended, but is different because technically, the AGM battery is still considered as wet cell. Gel cell batteries contain a silica type gel that the battery electrolyte is suspended in. This thick paste like material allows electrons to flow between plates but will not leak from the battery if the case is broken. The recharge voltages on this type of cell are lower than the other types of lead acid battery. This is due to the most sensitive cell in terms of adverse reactions to over-voltage charging. Gel batteries are best used in deep cycle application and may last a bit longer in hot weather applications.

Quite often AGM Batteries are mistakenly identified as Gel cell Batteries. Both batteries have similar features; such as being non-spillable, deep cycle, may be mounted in any position, low self-discharge, safe for use in limited ventilation areas, and may be transported safely without special handling.

Gel Batteries are typically a slightly more expensive option and do not offer the same power capacity as the same physical size AGM battery. With cycling and aging, the capacity of AGM fades gradually; gel, on the other hand, has a dome shaped performance curve and stays in the high-performance range longer but then drops suddenly towards the end of life. The Gel cell battery excels in slow discharge rates and slightly higher ambient operating temperatures. One big issue with Gel Batteries that must be addressing is the Gel Charge Profile. Gel Cell Batteries must be recharged correctly, or the battery will suffer premature failure. The battery charger being used to recharge the battery(s) must be designed or adjustable for Gel Cell Batteries.

Important Charging Note: If the incorrect battery charger is used on a Gel Cell battery, poor performance and premature failure is inevitable. Battery chargers with gel profile will have information either on the unit, or in the manual, about gel compatibility.