For those curious about voltage spikes, I finally dragged my scope out to the garage yesterday. I didn't do any 'moving' tests - just revved the motor in neutral. It requires 60-70 motor amps at a constant RPM, and maybe 150-200A depending how hard I 'rev' it.
The waveform looks very clean - stretching out the horizontal axis shows a small voltage spike. However, the vertical axis was set to 50V/square, so a little blip is actually 20V or so. Nevertheless, my pack is in the 160's if it's immediately after a charge, so a 20V spike still leaves some margin.
On my charger application, I noticed that there was a 10V voltage spike that was present and it was the same size no matter what the current or voltage was. This spike seems to grow as current increases, (though the battery voltage on my floodies also drops due to voltage sag) so I guess we don't really know how it's behaving under a more significant load.
Here's the video...