I have 2010 E90 which I have owned since new. It now has 110k and all services done thru dealer and exceeded BMW recommendations. Oil changes every 7000 miles. When vehicle is cold, around here 32 degrees, it does start but "labors" or strains for about 4 seconds. The cars always starts. The vehicles has 3 year old battery, this battery was installed by the dealer and registered, the car has new spark plugs, I have a battery tender which I use about every 2 weeks. I use the tender due to the short driving. I drive about 15 miles per day. The battery glass is green. When checked cold is shows exactly 12 volts on a volt meter. I was planning to replace the battery, but does this make sense? Will new battery have same problem in about a month or so. Due to short driving.