FYI on Optima battery charging as it cannot be done the same as cell batteries,

If an OPTIMA battery is deeply discharged (below 10.5 volts), most basic chargers will not supply a charge. Also keep in mind that an OPTIMA battery will not recharge properly if treated as a regular flooded or gel battery. To charge the battery, you can wire a second fully charged automotive battery (12+volts) to the discharged AGM in parallel (+ to + and – to –). Then hook up the charger to the deeply discharged battery, setting the charger at 10 amps. Leave for two hours, monitoring frequently. During this process, if the discharged battery gets very hot or if it is venting (hissing sound from vents), then stop this process immediately. When the discharged battery reaches 10.5 volts or more, remove the standard battery and continue charging the AGM until fully charged.

Fro