I've got FETs in my SE!

ph2t · Post by **ph2t** » Tue Dec 09, 2003 12:01 am

ahh, so you have run it through a sim? cool... we'll see what happens...

ph2t.

ph2t · Post by **ph2t** » Wed Dec 17, 2003 5:18 pm

I've just found this turkey over at MRCC selling the ZZSE fet mod:

http://www.microrccenter.com/forum/inde ... opic=18782

Basically it's the same as what we have done here already. He says though that if you doublestack all four fets (2*n-chan and 2*p-chan) then you do get a great speed increase. I've only stacked the n-chan fets (irlml2502) and not the p-chan ones (irlml6401). I'll give this a go this w/e and see what happens.

ph2t.

Post by **CaboWabo** » Wed Dec 17, 2003 5:22 pm

take him to school ph2t
put the exlamation point on his learned words
you got tha skillz to pay da billz

crazydave · Post by **crazydave** » Wed Dec 17, 2003 6:05 pm

ph2t wrote:I've just found this turkey over at MRCC selling the ZZSE fet mod:

http://www.microrccenter.com/forum/inde ... opic=18782

Basically it's the same as what we have done here already. He says though that if you doublestack all four fets (2*n-chan and 2*p-chan) then you do get a great speed increase. I've only stacked the n-chan fets (irlml2502) and not the p-chan ones (irlml6401). I'll give this a go this w/e and see what happens.

ph2t.

He's just blowing steam.

Stacking my FETs only helped slightly. I triple stacked my N-channels, and I think by that point it wasn't doing anything. Getting the FETs in there is the main diff.

Now if we can just figure out how to get the full voltage from the battery hitting those FETs, we're in business

ph2t · Post by **ph2t** » Wed Dec 17, 2003 6:20 pm

CaboWabo wrote:.......
you got tha skillz to pay da billz......

damn I love that song man! the world of ph2t according beastie boyz....

ph2t.

ph2t · Post by **ph2t** » Wed Dec 17, 2003 7:05 pm

crazydave wrote:
ph2t wrote:I've just found this turkey over at MRCC selling the ZZSE fet mod:

http://www.microrccenter.com/forum/inde ... opic=18782

Basically it's the same as what we have done here already. He says though that if you doublestack all four fets (2*n-chan and 2*p-chan) then you do get a great speed increase. I've only stacked the n-chan fets (irlml2502) and not the p-chan ones (irlml6401). I'll give this a go this w/e and see what happens.

ph2t.
He's just blowing steam.

Stacking my FETs only helped slightly. I triple stacked my N-channels, and I think by that point it wasn't doing anything. Getting the FETs in there is the main diff.

Now if we can just figure out how to get the full voltage from the battery hitting those FETs, we're in business

That's what I'm thinking. If you look at the datasheet for the irlml2502 fet you will see this graph:

The resistance (Y axis) decreases as you apply more voltage (X axis) to the mosfet gate pin. In Bit's we're applying 3V, so from the graph you can see that the resistance becomes 0.035 Ohms. The SEZZ only puts 0.9V to the mosfet and you can see that the resistance isn't even graphed! you can see the curve is now approaching infinity hence the high resistance.......

class dissmissed!

ph2t.

cyborgzero · Post by **cyborgzero** » Thu Dec 18, 2003 8:52 pm

ph2t wrote:I've just found this turkey over at MRCC selling the ZZSE fet mod:

http://www.microrccenter.com/forum/inde ... opic=18782

Basically it's the same as what we have done here already. He says though that if you doublestack all four fets (2*n-chan and 2*p-chan) then you do get a great speed increase. I've only stacked the n-chan fets (irlml2502) and not the p-chan ones (irlml6401). I'll give this a go this w/e and see what happens.

ph2t.

Er, thats not ALL i do BTW.

I am not going to give you ALL the goodies I do to it to get the speed increase..

I had to live through my ASET, 7 years of design experience, and now a Physics degree i am currently enrolled in. Figure it out yourself, turkey.

Rob

cyborgzero · Post by **cyborgzero** » Thu Dec 18, 2003 9:03 pm

My SE already can climb a 30 degree incline at near full speed with the tires spinning with the 3.4 NOS motor. Anymore power and it will cease to have a useful runtime.

But, you ARE right.. These things aren't even truly ON at the gate voltages, which is why I posted my notes with the gate voltages included.

But, with an H bridge, there are OTHER tricks you can do..

Rob

VooDooMafia · Post by **VooDooMafia** » Thu Dec 18, 2003 10:40 pm

cyborgzero wrote:My SE already can climb a 30 degree incline at near full speed with the tires spinning with the 3.4 NOS motor. Anymore power and it will cease to have a useful runtime.

But, you ARE right.. These things aren't even truly ON at the gate voltages, which is why I posted my notes with the gate voltages included.

But, with an H bridge, there are OTHER tricks you can do..

Rob

Well if you gots some idea on the mod post em up pimp

cyborgzero · Post by **cyborgzero** » Fri Dec 19, 2003 10:57 am

Okay, first off, did anyone notice that the gate voltages for the steering is 1.2v?

There lies a hint in the steering circuits as to how to get higher gate voltages..

Also, too, there is NO ONE stopping you from running an extra FET stage run to the gate voltage of the H-bridge.

Oh gee did I give it away?

Rob

cyborgzero · Post by **cyborgzero** » Fri Dec 19, 2003 11:17 am

OR you could replace the fets with fets that have a lower RDS(on)

There are many ways to get what you want

Rob

hue35 · Post by **hue35** » Fri Dec 19, 2003 11:40 am

Hell, dude... sounds like you got it nailed from all directions. How about doin' it for reals, then postin' up a tutorial with pictures and diagrams. That way idiots like me can make an SE worth having, and you get to be an actual, true-to-life smarty pants and get mad respect from da hood.

Or, you can just keep throwing out your hypotheses (which I barely understand a word of) and "taunt the halfwits" with your brilliance and stuff.

Personally, I think you should do the tutorial.

SilentWolv · Post by **SilentWolv** » Fri Dec 19, 2003 12:40 pm

hue35 wrote:.........can make an SE worth having, .....Personally, I think you should do the tutorial.

There'd be one appreciative pimp here man.

sessiz · Post by **sessiz** » Fri Dec 19, 2003 7:29 pm

hue35 wrote:Hell, dude... sounds like you got it nailed from all directions. How about doin' it for reals, then postin' up a tutorial with pictures and diagrams. That way idiots like me can make an SE worth having, and you get to be an actual, true-to-life smarty pants and get mad respect from da hood.

Or, you can just keep throwing out your hypotheses (which I barely understand a word of) and "taunt the halfwits" with your brilliance and stuff.

Personally, I think you should do the tutorial.

Couldn't have put it any better.

crazydave · Post by **crazydave** » Fri Dec 19, 2003 7:42 pm

sessiz wrote:
hue35 wrote:Hell, dude... sounds like you got it nailed from all directions. How about doin' it for reals, then postin' up a tutorial with pictures and diagrams. That way idiots like me can make an SE worth having, and you get to be an actual, true-to-life smarty pants and get mad respect from da hood.

Or, you can just keep throwing out your hypotheses (which I barely understand a word of) and "taunt the halfwits" with your brilliance and stuff.

Personally, I think you should do the tutorial.
Couldn't have put it any better.

I know.

I'm tellin ya, I'm gonna hire him as my personal post writer.