Going by your quote above, I'm suspecting that you are failing to completely recharge the batteries at the end of each day. People buy batteries, use them and when they go bad, they blame the battery, the charger, their dog, the wife, etc, when in most cases, it's the operator. Batteries are like expensive girlfriends, you put them away wet(discharged/partially discharged)and they will get angry and moldy(won't work to their full capacity anymore). Even the best brands and quality batteries "don't like" to be discharged much below 50%, some will tolerate down to about 80% discharge but that is the extreme low end. You must recharge them, and keep them on a charger such as the one mentioned above, CTEK or Battery Minder(VDC Electronics). They will maintain your batteries over the storage season. My boat battery is 7 years old, stil holds 90% load rating. Last year my RV battery finally pooched, but, it was 11 years old. Treat them right, they will reciprocate.