Optima is AGM, Sprial Wound AGM, it has roughly 60% of the capacity of the same size class Regular battery (Be it AGM, Maintenance Free, or Flooded wet cell).
Many people confuse Gel and AGM, because in many respects they are the same
Both are Valve Regulated Sealed Lead Acid batteries
Both can be mounted "This side up" or any other way you want to mount them, On edge, On end, Even upside down.. They do not leak and they are low gasing.
However there is a big difference:
Where as some AGM batteries can take recharge very very fast, (Lifeline at one point recommended an initial charge of up to 3 times the amp hour rating (20 hour rate) so a Common Group 29 could take 300 amps of charge.. Other makes do not make quite a bold a recommendation0.
GEL's need to be SERIOUSLY babied,, (Say 25 amps) and where AGM's are a bit forgiving of some abuse things,, GEL is not, not at all. Do not overcharge a Gel ever.
This is why GEL cells are usually restricted to use in electrnic devices that have a good charge controller, and are also usually only smaller (Single digit amp hour rating) batteries and even there AGM is replacing them.
