Read it. There is nothing preventing you from transferring some of the charge from your recharged battery to the dead one. But you get nothing for nothing. First off no transformer is perfect so there will always be some loss, eddy currents, resistance in the windings...
The bottom line is you can not transfer all the energy from one cell to the other by any method.
The other thing to note is you know nothing about the state of charge for either battery. Current readings mean almost nothing. If you want to know what WAS in the battery you can measure the discharge over time and integrate. Measuring peak current of a fully charged battery only gives you a peek at it's internal resistance. There are MANY more details that you are over looking. If I were you I would spend some time reading electronic theory. It's great to come up with "mad ideas" so long as you learn from them and come away with some factual knowledge. There has been more than one crazy idea that worked out. Not this one through.
The energy in a battery is really how many missing electrons you can shove into it. It's a function of mass and material.
