hp and monster controllers

howdy,

posted a thread a few weeks ago concerning stepping up a spec'd 24v motor to run at 36v. this one is similar.

for the big boys that are playing with etek and perm motors, most all of them are using serious controllers--100, 200, 300...i've seen zilla controllers rated at as high as 2,000A! When you do the math, if you're running a 2,000w continuous/10,000w peak (etek) motor @ 48v, you're pulling a little more than 40 amps continuous...and over 200 @ peak.

my question is, with discharge rates this high, what is the effect on the batteries? I understand NiCad can handle much more abuse, and SLA's i'm not sure about (though for many i have looked at they say not to discharge in excess of 40A.) what's the deal here? How can newer, higher performance packs (that subsequently caution against rapid discharge because of battery chemistry) supply the juice for these beasts without collapsing from exhaustion?

aside from the battery issue, i've also heard of guys using 24v motors with 100+A controllers, as if it were a way to get around stepping up voltage or using a different controller (i'm just making up scenarios). is there any advantage or reason for this, rather than operating at higher voltage with less amps (easier on batteries?)?

thanks much.

Rob