What’s the difference between an AGM versus gel cell battery

What’s the difference between an AGM versus Gel Cell Battery?

Many people use the terms AGM and gel cell interchangeably. Specifically, many car enthusiasts refer to the spiral-wound Optima battery as a gel cell. It’s not. It’s a spiral-wound AGM battery. AGM and gel cell batteries have similar characteristics, but they’re not the same, and gel cell batteries have never been used as starting batteries in automotive applications. An absorbed glass mat car battery (AGM) uses a liquid electrolyte that is fully absorbed by a glass mat and held tightly against the lead plates. A gel cell battery uses a gelled electrolyte.

Why the misconception about AGM versus gel cell batteries?

It all started with the Optima spiral wound AGM battery.

An Optima battery is not a gel cell. It is an absorbed glass mat battery (AGM). It uses a liquid electrolyte, not a gel

Because it’s sealed, people thought it was no different from other types of sealed lead-acid batteries, so they referred to it as a gel cell battery.

The Optima is not a gel cell battery. It is an AGM with a different plate structure. The spiral wound lead plates produce more power and can handle a deeper discharge and more charge/discharge cycles.

The shared characteristics aided the misconception

Often, AGM Batteries are mistakenly identified as Gel Cell Batteries, given their non-spillable construction. Both AGM and Gel batteries have similar traits, such as being:
• Non-spillable
• Found in Deep cycle applications
• Mounted on their side or standing up
• Low self-discharge rate
• Safe for use in limited ventilation areas
• May be transported via Air or Ground safely without special handling

A gel cell battery doesn’t work well in automotive applications

Gel batteries are designed to produce low amps

A gell cell battery would never work well as a starting battery in a car

for long periods of time, just the opposite of what you need in a car battery. The gel simply can’t conduct electron flow quickly enough to produce high starting amps needed to start an engine.

That’s why gel batteries are used in uninterrupted power systems (UPS), for their long run time. They’re also used to power alarm systems during power failures.

They’re both valve-regulated lead acid batteries (VRLA)

AGM and gel cell batteries do have some construction features in common. Both batteries recombine hydrogen gas and water during recharge to turn it back into electrolytes. And both have a high-pressure release valve to vent the battery in overcharge cases.

That’s where the term VRLA comes into play. It’s a pressure relief valve, kind of like the one on your home’s water heater. It’s a safety measure.

©, 2023 Rick Muscoplat