I gather you are speaking…
I gather you are speaking about the 12 volt battery and not the.main system battery.
There are several points on this topic. Are you plugging into a home charger daily or sporadically? Low mileage means its sitting around not being driven, allowing the 12 volt to charge.
A good AGM battery may alleviate the issue, but an old fashioned Trickle Charger used while idle maybe just as good.