2005 Buick Century battery size

Is putting a bigger battery than stock, not a good idea?

If it fits the battery tray and the hold-down clamps fit, there is no problem with installing a bigger battery. Just check for hood clearance and make sure the hold-down clamps are installed. Way too many people install bigger batteries and then can’t and don’t clamp them down.

This is assuming, of course that it is still a 12 volt battery!