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-   -   SS + ZZMT = SZMT, My SuperZip MT (http://tinyrc.com/forums/showthread.php?t=22768)

Jazz32 11-01-2006 05:46 PM

SS + ZZMT = SZMT, My SuperZip MT
 
1 Attachment(s)
I've always had a soft spot for the ZZMT. I've made a few quad cells but could never harness the speed very well. I decided that extending the chasis a bit would probably give it more leverage.

Before this project I had a quad cell with a 10 tooth pinion and orange motor and gears. This had a gear ration of 11.78:1.

I tested a ZZMT orange motor with 4V stalled and it drew around 1.4 amps. My quad cell with 5V then would probably draw around 1.6-1.7amps.

I had an idea to use a pair of SS motors for more power. I opted for the orange 22k. At 4V stalled, these draw just about 1 amp. I decided that I shouldn't go over 3 cells with a pair of these for fear of frying some FETs, which is still a risk at this level.

Jazz32 11-01-2006 05:50 PM

1 Attachment(s)
The project was to extend a truck chasis and use a SS Mini body with a SS pcb and controller. This would give me the "turbo" to help control the power a bit.

I wanted more speed though and this set up wouldn't give me much more than the prior quad cell.

Now, I needed to change the gearing. I looked at the transfer gears from the SS. They all have 10 teeth in the middle, same as a yellow ZZMT transfer gear. This made any a perfect match to the yellow ZZMT axle gear.

Cutting away the back of ZZMT chasis, I determined that red SS pinion gears and a Green SS transfer gear gave just enough room for easy mounting.

Here is a picture of what it should look like. I've tested it using 4V with one motor and there is quite a bit of torque from just one of those motors.

I wend 6 cells for a 3s2p connection hoping to get some better battery life with draw of these motors. Here is a picture of what it will look like soon. I will be working on soldering and getting the board in tonight. Hopefully it won't fry.

This worked well enough I might decide to make a crawler version.

Oh yes, 4wd is retained

Jazz32 11-03-2006 12:34 AM

So, I have a sad update.

I spent part of the evening wiring in the SS PCB. I charge up the batteries, pull the trigger.... It moved, slowly crawling on the floor.

So, something I should have checked in the beginning... how much power does the pcb send to the motors. Like the zipzaps, the SS's use a duty cycle, pretty much haulting this project.

At a full charge ~4.0V with both motors stalled, the motors were only pulling around 600-700mA. With 2 AA nimh cells hooked directly to the motor, they pull around 1100mA.

The power difference is disheartening. With the 2 AA's, it would slowly spin all 4 tires on the kitchen counter pushing against my finger. With the SS pcb and ~3.8V, it would barely nudge my finger....

I drove it around on the floor and it worked, but it's acceleration was sad.

Look to see this project moved to the ZZMT forum. I will be continuing the project by switching back to a ZZMT board.

fatman 08-22-2007 09:40 AM

well it takes 4 volts on power board of suprslick
 
and 1.9 on motor the problem is voltege and u are killing car with 2 motors one is moving faster and slowing down from other


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