The Sub-Genius MOSFET mod

ph2t · Post by **ph2t** » Thu Nov 06, 2003 6:19 pm

The two flipped mosfets have one pin that is NOT connected to the PCB. This pin is connected to the red and black wires in the pic that connect to the other 2 (normal side up) mosfets.

ph2t.

vinnyg · Post by **vinnyg** » Thu Nov 06, 2003 8:52 pm

thanks alot guys, i knew that one pin was not connected but id didnt know that the fets in the color diagram were flipped. thanks

ph2t · Post by **ph2t** » Thu Nov 06, 2003 10:19 pm

Shamon!

pimpsmurf · Post by **pimpsmurf** » Fri Jul 01, 2005 4:07 pm

I can use IRLML6401 instead of IRLML2502 for the two that have one hanging off (and flipped upside-down?) I think. Do I still have them hanging off as shown or do I put them on the way God and Radioshack intended?

Thanks, (took forever to find the non-SE ZZ FET Mod info!!!)
-JNY

crazydave · Post by **crazydave** » Fri Jul 01, 2005 6:27 pm

The IRLML6401 is a P-channel FET and is a direct swap in the positions that are flipped in the diagram.

We flipped the FETs early on because we used all N-channel FETs, and had to flip the 2 that were replacing P-channels. We did that, well, mostly just because that's the way the Germans did it, but the theory is that the N-channels have a slightly lower on resistance than the P-channel FETs.

When figuring out the FET mod for the SE, it was ph2t that pointed out (hopefully I get this straight) that the on resistance rating is at 5v, and since the P-channels turn on at a lower voltage, they might actually have a similar, possibly better rating at the voltage we're using.

I've been just using the P-channels along with the N-channels, because it's easier to just swap the FETs straight in, it looks cleaner, and I really don't detect any noticeable difference in the car's performance.

Didja get that, or did my elaboration just lead to confusion?

SuperFly · Post by **SuperFly** » Fri Jul 01, 2005 7:08 pm

Hmm. I kinda went through a little mosfet hiatus about the time y'all were figuring out P and N channel FETS. I would love to be able to avoid all that flipping, rotating and running wires everywhere. I'll have to check into it.

pimpsmurf · Post by **pimpsmurf** » Sat Jul 02, 2005 3:20 pm

crazydave, dude. you rock harder than steel man.

So, your saying that the flipped N channels are replaceing pchannels and the p channels that I ordered go on the good way God intended (a direct replacement in the same orientation as the original FETs); correct?

If so, I don't feel so bad. All thats left to do is wait for my parts and modify my body so that it can handle the Radio shack Wide tire upgrade I put on the front.

-JNY

SuperFly · Post by **SuperFly** » Sat Jul 02, 2005 3:30 pm

pimpsmurf wrote:the p channels that I ordered

You got a link or a part number for the p channel FETs? I know I should know better and do a search but I'm feeling lazy. Thanks.

crazydave · Post by **crazydave** » Sat Jul 02, 2005 6:52 pm

pimpsmurf wrote:So, your saying that the flipped N channels are replaceing pchannels and the p channels that I ordered go on the good way God intended (a direct replacement in the same orientation as the original FETs); correct?

You sir, are correct.

Here ya go Superfly:
http://www.digikey.com/scripts/DkSearch ... 52&Site=US

pimpsmurf · Post by **pimpsmurf** » Wed Jul 06, 2005 8:48 am

Thanks CrazyDave!

Superfly: search IRLML6401 at digikey.

You guys wouldn't believe the packaging they did for these buggers! That is to say, I got mine in today. I'm going to doublestack forward and single reverse with steering FETs. As long as I have enough for my OG ZZ, and my MT. I got a ZZSE yesterday too, but it is acting up. Thats for another thread though!

The kind of self control I can't pull off,
-JNY

"Call me Mr. Courtious..."

pimpsmurf · Post by **pimpsmurf** » Wed Jul 06, 2005 9:11 am

how about this one? Which FETs are forward, and which are reverse and steering?

I'd really hate to doublestack my steering on accident!

*edit*
Turns out This doesn't work quite the same on OGZZ as Bits. Good thing I have a bit on the way!

I'm absolutely going to FET mod my OGZZ. I don't really know how, but I know which are the steering, and which are the motor n & p channel transitors. I'm going to MOSFET them buggers somehow. I'm not sure how the self gating( or driving or something or other) works (I.E. Which, if any, resistors I need to jumper, but I will figure it out. That is unless someone helps me out.

Also, I never realized holes in your conductors are important! (This new book owns all!)
*edit*

-JNY