How to Tell the Difference in Gel, AGM or Standard Batteries

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Lead acid batteries are used throughout the world in cars and boats. Lead acid battery construction now includes both gel and AGM (Absorbed Glass Mat) technologies as well as liquid lead acid.

It is important to know which type you are using. Each battery type requires different handling procedures. A mistake can shorten battery life or harm the battery or user. Choose any one or a combination of steps to determine your battery type and care instructions.

Liquid lead acid batteries, or wet cells, are the most common lead acid battery type. AGM batteries, or dry cell batteries, are the newest type of battery, and can be substituted for wet cell batteries. AGM batteries are safer and more durable when being moved from place to place, but can easily be ruined during the charging process

Read the battery label. Liquid--or flooded--lead acid batteries will say "lead acid," “wet cell,” "flooded lead acid" or "liquid lead acid" on the label. Gel-filled lead acid batteries will say "Gel-Filled" on the label. AGM lead acid batteries will say "AGM" or "Absorbed Glass Mat," "sealed regulated valve," "dry cell," "non-spillable," or "valve regulated" on the label.

Look at the top of the battery. Liquid lead acid batteries have caps or removable tops unless they say "sealed" on the label. Gel-filled and AGM lead acid batteries have flat tops except for the positive and negative terminals.

Shake the battery. Liquid lead acid batteries will wiggle when held still after a hard shake. The liquid center will continue to move for a moment even if the battery is sealed. Gel-filled and AGM lead acid batteries will not wiggle when held still after a hard shake.

Look up the manufacturer model number on the battery label. The manufacturer and manufacturer's model name or number is on the label or embossed on the case. Use it to get specifications from a battery store or the manufacturer's Internet site.


  • Be careful with wet-cell batteries. The acid in the battery will burn human tissue. If the acid comes into contact with seawater, chlorine gas is produced.

    Gel and AGM batteries can be easily damaged if the charging current is too high.