A too-dead-to-work battery can take a full charge of 12.6 volts or more but have too little capacity to get its job done. This shows on a load test. I have a battery just like this on a chipper. One clue is that it recharges too quickly from dead to "full charge." And then it just gives about half a crank of the engine and no more.The battery was dead. Our tester said it was full but his said dead.