I did some poking around the ZZ pcb to figure out why the ZZ is slower than other cars with the same battery and motor. Here is what I found:
With a battery voltage of 1.29v the motor only sees 1.12 under no load conditions (wheels in the air). This tells me that the speed controller on the board has an on resistance of around .5 ohms or more which is pretty crappy. Figures based on a load current of 200ma which I guestimated. There are a couple ways to improve this:
1) Solder additional MOSFETS to the board. This will halve the on resistance for each additional MOSFET. Maybe someone has access to some SMT FETS....I dont. Unsoldering them from a trashed ZZ board is an alternative I supose.
2) Disable reverse. A reversing speed controller is made from a 4 MOSFET circuit called an H-Bridge. Two FETs run forward and 2 run reverse. A speed control with only forward needs only 1 MOSFET and has half the resistance of a reversing one. Reverse is real nice....not sure that I would race with it disabled.
**** HERE'S THE MOD ***** DO THIS AT YOUR OWN RISK....IF YOU BLOW UP...ITS NOT MY FAULT!!!!!!
1) clip the yellow wire right at the PCB.
2) this leaves you with a yellow wire that is connected to the case of the motor (right)
3) Solder this wire to the + side of the battery....look for the red wire and solder it there
4) you will have the yellow wire (case of motor) connected directly to the + side of the battery (right)
5) Charge and run the car....reverse wont work, but you will be faster.
Q: Why does this work?
A: Because you are bypassing the MOSFET that controls reverse. This reduces the speed controllers on resistance by about 1/2 (maybe a little more...too many technical details to write about)
DO THIS AT YOUR OWN RISK....IF YOU BLOW UP...ITS NOT MY FAULT!!!!!!
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More stuff to consider....with reverse disables that means that there is a MOSFET that isnt being used. It should be possible to unsolder it and resolder it across the one MOSFET that is used for forward........just a thought.
Speed Boosting ZZ PCB Mod
Threaded Mode
