CX500 GL500 650 Global

It's a common misconception that a,"Bigger" battery will put out more current.Batteries don't work that way.They are a storage device,not a generating device.Under none short situation they only supply what is demanded of them.
All Automotive batteries have a working voltage range usually between 10v and 15v Max although sold as 12v as that's their standard operating voltage.Most charging circuits on motorcycles/cars supply around 14.5.v whilst running to keep re-supply the current drain from usage and this changes as per running conditions but in a nominal charging circuit will be above the 12v margin.
Automotive batteries/accumulators have two current ratings.Their standard amp hour rating,in the case of the CX500s 14 Ah(Amp Hours) which basically it can supply 1 amp for 14 hours or variables of that and a,"Cranking Current" which is the maximum current the battery can supply in a short burst as in when the ignition to starter motor is engaged.In this case 180 amps depending on the make of the battery.