I just took my 4 month old Walmart 29dc TM battery back for a warranty replacement today. They gave me a new one. Was only putting out 8.5 volts and would not take a charge throwing fault code on my smart charger. This battery has always been weak and I think it was bad from the get go. Always charged it immediately after use and kept it on a battery tender.
I guess the lesson here is to get the best you can afford.
From Genesis: "And God promised men that good and obedient wives would be found in all corners of the earth."
Then He made the earth round...and He laughed and laughed and laughed!