New battery installed first start lights on dash turn the key totally dead for 4 to 5 turns then sixth time nearly cranks next turn starts up and starts up then all day MERCEDES-BENZ

New battery won’t start in the morning lights on dash 4or5 turns of the key totally dead then 6 th time half a crank then it starts ok it’s been fine until Monday done exactly the same with old battery advised it was the battery as it was 30 on the meter put the Varna new battery on same again this morning