fet help

[demon]

i did a (2stack4high)fet upgrade,i have a studder when i hit the throttle,after a few ft it takes off,how can i fix this,thanks,i posted this i another section,didnt get any hits.

[aperson]

IDK about the studdering but how well does that fit.

[demon]

it hangs down below chassie,so i took 2 off the stack,now its flush with the bottom,i wish someone could give me an idea on this studder

[aperson]

so you stacked them on both sides right? top and bottom

[demon]

if u go with more stock fets u just stack them on top each other,the 2 on the bottom are the ones u need to stack,not the top

[neurokinetik]

Did you check your solder joints with an ohmmeter to make sure they were solid? You do also realize that by not having the tops of the FETs in contact with the aluminium heatsink, that you are reducing the power-handling capacity of the chips, right? Speaking of that heatsink, make sure the pins on the FETs are not touching it where they come through, unless of course, you took it out completely. Also make sure the board is not being pushed up against the driveshaft, shorting it out.

[demon]

neuro,have u done a 2+3stack of 4562s on a xmod,if so did it work fine,i checked all the legs.im working on it out of the car.its not noticeable if the motor is out,but when i put a load on it ,or put pressure on the pinion it studders,then i let go it revs fine,its a tq problem

[neurokinetik]

Originally posted by demon
neuro,have u done a 2+3stack of 4562s on a xmod,if so did it work fine,i checked all the legs.im working on it out of the car.its not noticeable if the motor is out,but when i put a load on it ,or put pressure on the pinion it studders,then i let go it revs fine,its a tq problem

I just did my first 2x3 stack this weekend, but it wasn't on an Xmod, and I was using IRF7389s. It works flawlessly, however it did take me two attempts to get it right. Word of advice, pay attention when you are stacking, I got distracted and put a FET in the stack backwards. Luckily I noticed the batteries getting warm right away, took them right back out, and fixed the problem. Even though I never saw or smelled smoke, I assumed that all the FETs in the stack were shot, so I didn't reinstall them, I made a new stack.

[demon]

i started with a 2*4stack ,took a row off, studder didnt stop,i took a shot at taking another stack off(2*2now)and walla its fixed.i thought i heard of people putting2*4stacks on their xmods,dam if i can.2*4 is to much anyway,it hangs below the chassie.it took me an hour to stack 4 high taking my time making sure everything was good,a lttle dissapointed i had to take half of them off,now i can continue building some motors. but its fixed now,thanks for your help

[Doctoraudio]

Does anyone have any pictures of the MosFets heat sink or pictures of the bottom of the car that have the heatsink showing!
I am ready to do the mods to my cars and just want to see what they look like!