mbzman, the batteries our local MB dealer sells fit in the battery tray of our 1991 & 1992 300CE's with room to spare. Don't understand why your 1989 300CE battery tray wouldn't be the same configuration. Certainly wouldn't want to have to jerry rig a hold-down for the battery. So I will continue to buy replacement batteries from our local MB dealer.

From what I have read Optima batteries are sealed and maintenance-free; however, the positive and negative terminals may be reversed, requiring a wiring modification.

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Fred Hoelzle