question for electronic guru's

[shaunjohnson]

from what ive seen in castles ESC's, cogging is next to nothing.
added to the fact that the motor chosen will have LOADS of poles, hence reducing cogging to next-to-nill.
lots of little fets might work but i'd rather mega fets if they are avaliable.
fets job is to take a small electrical signal and switch on some serious power. so a mega fet might take 10A on the signal to switch it...i wouldent know!

my manette has tons of space under it for batteries, so no internal space would be needed to be taken up. once the fuel tank is gone (80 liter) then there is about 2 square meters of total space under there. must measure that some day.
i'd love this project, sure people have made electric cars and some are pretty damn fast...but that was BRUSHED!!!.........AND LEAD ACID BATTS!!!! and to me that's silly.
so i want A123 cells all the way baby, A123 systems have cells avaliable for large projects like this.
i can see it now, the old shat box that usualy sits in the corner of the school carpart that is always leaking diesel, suddenly just starts rolling out of the carpark with no engine going...

[BrianG]

Originally Posted by shaunjohnson

...lots of little fets might work but i'd rather mega fets if they are avaliable. fets job is to take a small electrical signal and switch on some serious power. so a mega fet might take 10A on the signal to switch it...i wouldent know!...

Using many FETs decreases the on resistance for better efficiency. A single large FET may not have ideal resistance, switching speed, etc as many smaller ones placed in parallel. And, FET gates are voltage driven (very little current). I like to think of FETs like a garden hose where the input and output is the hose and the gate is a set of fingers squeezing it to limit/stop current.