Hi! This is my first post here. My first Arduino boards (Uno and Mega) just arrived yesterday! I am new to robotics, so please excuse my ignorance. I would greatly appreciate if you could explain your reasoning as well, so that I can learn to make my own decisions ...
Background:
I am building a rover to mount my camera, for wildlife photography. Given the nature of the work, it will involve short distances with plenty of starts, stops and maneuvering.
I have purchased a Dagu Wild Thumper 6WD chassis, and there is some confusion about its motors. Pololu states that each motor has a stalling current of 6.6A, and since there are 3 motors per channel, they recommend a motor driver capable of 20A per channel.
However, the manufacturer specs state that the locked rotor current is 5.5A. The continuous current required is not stated, but I assume it will be about 25% of that. If my reasoning is correct, I shouldn't need more than 5A of combined current per channel (for 3 motors).
The problem:
Firstly, I am unclear on what the specs of my motor controller should be (I'm restricting myself to dual-channel controllers). Should I go for a controller that supplies 25A, 30A etc.? Or can I do just fine with a controller that supplies 10A or 15A continuous, with a peak of around 30A?
It's a problem of cost:
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Sparkfun Moto Shield supplies 14A continuous, 30A peak, but costs $70. I'm not sure if 14A is enough for a 6WD (based on Pololu's recommendation)
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Sabertooth offers a powerful $125 controller with 25A continuous, but I wonder if this will be overkill (and needlessly expensive). I've seen some Youtubers using this controller, but I don't want to go this route if it isn't necessary.
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At the other end of the spectrum, there are these super-inexpensive Chinese controllers...
... Like this $25 15A (30A peak) controller, with heatsink and all
... Or this one that merely states a 30A figure and costs only $16. :o
It's the price that's a little disconcerting. Since I am a newbie, I can't tell if there have been any compromises in quality. Of course, I'd rather spend $20 instead of $70 or $125. What's the catch?
Final thoughts...
What other features should a motor controller have? There are some that offer RC control. Is this a deciding factor? I think that RC will be my only feasible option in the wild, vs. wifi or bluetooth. Does it really matter if the MC offers radio control?
And will I need a 2nd controller for video feed (so that I can steer the rover remotely)?
If you've read this far, thank you for your patience! I look forward to your response. As I said, I am totally new to this, so I highly appreciate all your help and advice!