Hi Paul. You have a few options and that spark fun controller may not be a good fit. It is both the h bridge and also a arduino microcontroller. You should get two more 298n controllers in the ez robot store and each set of motors would have their own low cost and low heat h bridge. You would just parallel the power, signal and ground wires . One for the right side and the other set of power signal and ground for the left side. That's a 30 dollars cost and you can directly control it with pwm control from ez board. Again because that board is meant to be a stand alone system i do not recommend that one.

Josh is super right. I think you were in contact with Alan earlier today. He asked me about the thumper and the 2.5 amp controller. We updated the store description for the thumper to reflect the suggestion that you'll need 3 of the 2.5 controllers. An hbridge (wether sabertooth or not) will require an hbridge per set of motors. Running more than one motor in series or parallel is terrible for power consumption. It's practically impossible to predict the draw of each motor individually and therefore creates an issue.

So affordable low cost controllers for each set of motors is recommended.

Btw, they should be connected in parallel (the controllers) to use the hbridge motor control panel on ARC

Many thanks Josh and DJ

So just want to check your last point DJ. You are saying that:

1. Each motor should be connected to an individual H-bridge

2. The PWM inputs for the 3 H-bridges for the motors on each side of the Thumper should be connected in parallel and then connected to the EZ-Robot PWM output so that they can be controlled in parallel by the hbridge motor control panel on ARC

Is that right?

Thanks

I will post one of my low budget illustrations tonight for you

Before we get Josh's awesome illustration, can you tell us how many volts and amperage your battery source is?

I was thinking of one of these: Extreme Track 6000mAh Lipo Battery 2S 7.4v 60C Constant 90C Bursts (http://www.overlander.co.uk/batteries-chargers/lipo-batteries/sport-track-pro-6000mah-lipo-battery-2s-7-4v-60c-constant-90c-bursts.html)

Thanks

Did the illustration get posted somewhere?

Out of curiosity and of desire to assist others with practical advice, as many have done for me over the years... Why advertise that the Wild Thumper 6WD needs three 2.5A underrated (for this chassis) controllers instead of one properly rated one? (30A MAX recommended for 6WD)

The Dagu Wild Thumper chassis come with motors pre-wired for paralleled use (per side of course) And as long as the drive controller is rated (safety wise) for the total stall capacity of all parallel wired motors then all is good! I.e. three 7.2v DC motors, each rated for 6.6A at stall (well over the 2.5A of the recommended controller) will only ever draw 7.2v and total of 20A (assuming ALL stall out simultaneously, more if rapidly changing directions). If just one stalls or is "off" then the remaining two still only draw 7.2v and whatever current they need.

There is no practical need to have separate controllers... I agree that it technically can be done... but, for a new robotics builder, suggesting such actually complicates things not simplifying them.

I do however totally agree with @DJ that wiring drive motors in series is just asking for trouble A change in one WILL affect all others, usually to the negative.