[jhautz]

The over discharged bateries may have limited the number of amps that the whole battery pack can supply and as a result of the low amp capability you get lots of cogging. Just like if you use cheap cells. they cant deliver the amps required and the system doesnt run right. Cogging is about the worst thing you can do to your esc and if you dont let off the throttle when it startes to cog you are going to tax that esc pretty hard. Also, as Patrik said, the 7018 is rather small for an emaxx and the 28/66 gearing is rather tall. All of these things combined and Im not surprised the esc was smoking. If the esc smells burt... it is burnt. I'd recomend getting at least a 9920 or the mamba maxx and you should be in much better shape.