I got fed up with my 3004 fets on my MR-01 board (currently in my 010 AWD), but didn't want to spend 20-30$ on 4562 fets.. So I managed to order some Vishay Si4501 fets instead for about $1.60 a piece. Put together the double-triple stack, and it worked beautifully, no lag whatsoever.
Note these 4501 are made by Vishay and not by Fairchild, (the specs are quite different)
They are not quite as efficient as the 4562s, but handle up to 9amps on the N-channel. Still only 6.2A on the P-channel, so it really doesnt matter.
To test it out I ran it using my 27 turn plasma dash armature with Neo magnets. I ran it for a good 15 minutes until the batteries ran dry. Once they start dropping, they drop SOOOO fast.. I only got about 1 lap in when they started dropping.
The motor got so hot it melted the chassis plastic where the motor heatsink clips onto, and the heatsink fell off! I was worried since the smell of melted plastic smells a lot like burned fets. The fets were perfectly fine though.
When I picked it up and touched it, the fets themselves felt only a little warm, but the motor was scorching hot. I think I may have melted the armature and shorted it a little, becuase now the motor draws 9amps on stall, it only drew just under 5 on stall before if I remember correctly.
So I threw in my Xspeed armature in the atomic can, and ran for thrity minutes with some new cells. Ran beautifully, and the fets were cold.
For comparison, my AWD with 3x2 Si4501 with 19/29 gears + xspeed was about the same top speed as a friends AWD 1x2 Si4562 with 21/27 gears + xspeed.
So.. I'd still say the Si4562 are still slightly better for Mini-Z, but the Si4501 are still quite good!
I know the Vgs for the P-chan is under than -4.5V usually, and the
Vgs N-chan is only around 3.0V in the mini-z, but just as a general
estimated comparison:
About 0.011Ohm difference in total resistance for a single stack, and for a triple stack it would be one-third that lets say 0.004Ohms. Even at a 4Amps draw, the resulting voltage difference between the 4562 and the 4501
triple stack is only 0.016 volts! Estimated one third of 1% difference in
peak voltage going to the motor..
Last edited by CrashTestJohnny; 2007.01.29 at 03:07 AM.
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