Originally Posted by a64pilot
... I thought yellow top were deep cycle, red starting and blue a hybrid.
More or less.
Optima AGM Batteries
REDTOP (Dark grey case) = Starting Battery
YELLOWTOP (Light grey case) = Deep-Cycle
BLUETOP Dark Grey case = Starting
BLUETOP Light Grey = Starting and Deep cycling (hybrid)
The difference between BLUETOP and YELLOWTOP deep-cycle batteries
is that BLUETOP batteries have both automotive (SAE) posts and threaded studs, while YELLOWTOPS (other than D31T) only have SAE terminals.
Dark Grey Cases are always Stating (SLI), whereas Light Grey cases are always Deep Cycle.