Why Does My Key Fob Battery Keep Going Dead. Have a helper try to start the car. Battery keeps going dead but only at home.

The way to check a battery for a bad cell if no major equipment is available except a voltmeter is as follows. The dealership blames the key fob. A dead battery cannot be tested.
When they do you may not be able to enter the car.
I have a 2012 Mazda3 Skyactiv hatchback. Battery and door key inside the key fob. At first I thought it was the key fob I had that was having the problem - however the dealer owed me a second key which I received on Monday. Why isnt my car key working.

