RE: Rudman Was Right! (was Dualin'7s Smoked Controllers)

[RichSJ@aol.com]

>'Course, if you can only get 1460A with a bypass, then that suggests
>that is all the current you can force through the motors once your
>pack sags under load, so the controllers would presumably be limited
>to the same ~1500A instead of their full 2400A potential, but why
>shouldn't they be able to force it through the motors up to just about
>the same RPM as the bypass since the only advantage of the bypass
>should be a somewhat lower voltage drop between the pack and motors
>than the FETs achieve?

The controllers are only able to supply 1200A for a very brief time but, you 
would think, that together they could manage all the current my batteries 
could dish out and my motors could suck out of them. The controllers cut back 
to 500 battery amps each after a very short time. The bypass contactor makes 
the D'7 faster by about a whole second on the 1/4 mile.

>Madman has written in the past about his frustration with trying to
>get Goldie's single 1200A controller to actually suck the full 1200A
>from his single string of YTs, and while I don't know how close he has
>got to that magic number I'm pretty sure he is doing considerably 
>better than the 675A peak [per controller] you're seeing... sure would
>be interesting to hear his comments on this!

Goldie has a single Raptor. He can stuff ~700A into his motor on a good day 
from his single string of YT at 156V. My batteries are smaller and sag 
slightly more than his, thus I get slightly less amps through the 
motor/controller. When I use the contactor, I get about the same amps through 
my motor as Rich Rudman does. It must be the motors inductance that limits 
the current flow when the contactor first connects, because the batteries 
have a 2600A short circuit current if you drop a copper bar across them. Of 
course at that rate, they blow-up and burn.  :-)

Roger, you're wearing me down!  :-)

BFN,

Rich Brown
San Jose, CA
Dualin'7     144V, 3200lbs and 14.990 in the 1/4 mile