"It's always the battery."
Check the water in the battery every week or 300 miles (whichever comes first) as the Honda owner's manual instructs. Add only distilled water to the battery. If you follow these directions, it may last you as long as 5 years, but most people get only 2-3.
You NEVER add electrolyte to a lead-acid battery after its initial fill when new (nor do you add anything to a maintenance-free battery). The chemical reaction of discharging a battery turns the highly concentrated acid into mostly water. Charging it changes the water back into acid again as the lead sulfate and lead oxide turn back into pure lead. This is a highly simplified version, but it basically explains it.