I build a galvanaised steel wire-dampening-batteryplatform, as described in the Maker Trainer II-series.
The wires were much longer. The downside was that when moving, flying the battery-tray could swing and thus added INSTABILITY to the rig, which the FC had to work hard on getting rid of.
I replaced the wires with some piano-wire as it is used in David Windestals solution and that worked nicely.
Now I really might try Chad's solution as well. The short wires, actually do a good job of dampening, BUT do not provide lots of swinging-motion.
There is one drawback though. In CHad's solution, the battery is exposed from the bottom and will have a big chance of taking a big hit when crashing.