question

You should never equalise gel ,agm, batteries. Only flooded lead acid cells need equalising

DO NOT equalize Gel and AGM.

This in my opinion is a general rule for MOST lead acide batteries unless otherwise stated by the manufacturer. and even then be very very carefull

GASSING IS BAD
Equalization is not good for batteries because it requires eventual replacement of the electrolyte. It is a necessary evil required only for flooded batteries to mix up the electrolyte if the battery has been sitting unused. Equalization is only required if the battery is sitting for weeks at a time. Vehicle motion also mixes the liquid, so equalization is not needed nor good for the battery if it is frequently in motion. Stratification is where the heavier, more acidic solution sinks to the bottom of the cell. Equalization produces bubbles that mix up the top and bottom. These hydrogen bubbles are replaced by adding water, or with a sealed battery, eventually recombined with the electrolyte. With a totally sealed battery, you may see the sides bulge, which could be normal.

GASSING IS REALLY BAD FOR GEL AND AGM
Gel and AGM cells do not have a free-flowing liquid solution and equalization will only cause gassing, not mixing. Gassing is not necessarily good because water will need to be replaced. However for GEL and AGM, the gas will either:

- If the gas pressure is BELOW the valve cap set pressure point it will eventually recombine with the gel or AGM electrolyte.
- If the gas pressure is ABOVE the valve cap set pressure it will BLOW out of the cap. You will hear the hissing of hydrogen gas. Not good since you cannot replace the electrolyte. A little gassing will not destroy the battery, but continued equalization will.