How to Rule out Hidden Batteries Inside Ecats?

As we look forward to the December 9th E-Cat presentation, one question I would like to throw out to the ECW audience is: how can we rule out that energy coming from the Ecats is not simply coming from hidden batteries?

I think that it is going to quite difficult at first to convince a skeptical audience that the Ecats use a radically new energy source, and there will be many observers who will be looking for a more mundane explanation for the energy measurements.

To carefully evaluate the Ecats, I think we will need to get accurate measurements of the units, and accurate weights of the unit. I hope that this information will be provided as part of the presentation. If we have that information, then I think we will need to have the ecats run long enough to rule out any possibility that they could have a battery inside of them (I am sure that Rossi will not be allowing either the Ecat SKLed or the Ecat SKL to be opened up for examination on camera)

So my question is, what is the best battery out there in terms of energy density? Once we get that information then we can do fairly simple calculations to see how long the runtime needs to be to rule out the possibility that this battery is hidden inside.

Thanks in advance for any thoughts!