6 Wheel drive antweight?

Shakey · Post by **Shakey** » Sun Oct 31, 2010 9:33 am

I have decided to build one of those pushbots as well as assailant so I always have at least one ant working. Assailant has.... reliability issues. I had a thought that I won't be one of those boring 4 WD ones but a boring 6WD one!

However I need your advice on speed controllers that could run 6 of them. 3 to each 'terminal' and also what sort of lipo batteries. The motors I have planned have a draw of 40mah.

Cheers,
Haywire

Simon Windisch · Post by **Simon Windisch** » Sun Oct 31, 2010 10:00 am

http://www.robotcombat.com/products/0-SABER2X5-RC.html

But first do the maths on motors plus wheels plus mounts times six!

Shakey · Post by **Shakey** » Sun Oct 31, 2010 12:47 pm

I've already checked the weight with the motors and wheels I plan on using it is 11 grams for each 'unit so 72 grams overall. the allowing 20 grams for the battery (generous!). Receiver and motor controller are still to be decided as I still need some advice.

What would be the effect on a motor controller running 6 80mah motors? Would they just blow when the motors draw more current such as starting assuming a 5amp rating?

Post by **BeligerAnt** » Sun Oct 31, 2010 2:36 pm

You need to know the stall current of the motors - significantly more than 80mA!
Multiply this by 3 and see if you exceed the current rating of the speed controller. Since the stall current is a peak value, this is a conservative rule-of-thumb, so you could probably get away with a bit more, especially if the speed controller has a peak current rating.
Stall current can be calculated from the DC resistance of the motor if it is not specified by the manufacturer. Current = Voltage / Resistance

Without knowing the details of the motors, I would guess that a 5A controller would be OK for typical ant-sized motors, but you do need to check to be sure.

Simon Windisch · Post by **Simon Windisch** » Sun Oct 31, 2010 3:58 pm

From the link above

Out of the box, it can supply two DC brushed motors with up to 5A each. Peak currents of 10A are achievable for a few seconds. Overcurrent and thermal protection means you'll never have to worry about killing the driver with accidental stalls or by hooking up too big a motor.

Post by **BeligerAnt** » Sun Oct 31, 2010 4:47 pm

A 10A peak rating should be more than enough, and with overcurrent and thermal protection, it sounds like the Sabertooth should be more than man enough for the job.

Shakey · Post by **Shakey** » Sun Oct 31, 2010 5:11 pm

The motors have a stall current of 1600 mah so 3 would be 4.8A?

So a 5 Amp controller should do the trick then?

haz · Post by **haz** » Sun Oct 31, 2010 5:44 pm

just saying, couldnt you use timing belts or pulleys to make it 6wd, but just with 2 gear motors?

Shakey · Post by **Shakey** » Sun Oct 31, 2010 6:11 pm

I could but then I don't have as much torque as using 6 motors would, Bear in mind things like defiant need to be pushed!

Jonny · Post by **Jonny** » Sun Oct 31, 2010 6:42 pm

haz wrote:just saying, couldnt you use timing belts or pulleys to make it 6wd, but just with 2 gear motors?

exactly what i'm using for 4wd