Makes me wonder if a Speeduino board could be adapted in some way to make a mapped motor controller. Modify the firmware (If needed) to provide a PWM output via a injector channel(s). Then you can use the various map methods along with the input channels to control the motor.
It would certainly be possible to use another board to control most motor controllers.
Ideally a combined controller / BMS / DC-DC control board for mid-size motors could be made that is advanced, flexible, and compact. But even motorcycle manufactures like Zero tend to only make what they need to in-house, in their case the just BMS. They use Sevcon / Borg Warner motor controllers and DC-DC converters instead of rolling their own. The on-board chargers are also 3rd party. Maybe that is smart, since all that custom R&D didn’t help Alta Motors long-term (along with pairing with HD).
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I’m still waiting to get the bus bars laser cut, but battery support frame construction has proceeded. Pictures tomorrow hopefully (drag it all outside in the sun), but for now here is a teaser of future things.
Just for fun I quickly rendered what my clean-sheet EV kart would look like using the new (future) Tesla 4680 cells, 40s1p. I rather like it… a LOT less spot welding required. 
BTW, the black box is what a kart has to fit in to be legal in KART.
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Are these new tesla batteries lighter? Not that you’d change it at this point.
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You were definitely right about the spot welding. I like cell-level fuses but it is definitely a pain to spot weld so many batteries. Even making small prototypes takes time. Definitely safer in the long run however
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Finished cutting all but the forward battery tab, ready to start welding. I think this will work great (if a bit heavy). Should be plenty strong.
Shown with bare battery base. Area scored to the left will be cut out for wheel clearance.
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Sidepod battery holder welded. The OEM sidepod bar can slip on and off separate of the battery holder, but it is attached by the front bolt for now. I need to get it painted today and decide what to do with the sidepod plastic. I can cut the current one at the front to start with, but something thinner would be nice long term to match both sides up.
Is the spacing on these mounting points somewhat standard for adult karts?
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I think so, although I have never measured it.
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Curious about this question too. Is the distance as shown by the yellow highlights the same for all karts?
EDIT: I fixed my pathetic grammar
FWIW the distance between the pod mounting sockets on my chassis is 17 3/8 inch. centre to centre.
This is an old chassis and may not be representative.
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Meassuring over my wider tubes and subtracting the width of one tube, my 08 CRG chassis measures 19.727 inches. Converting this to Metric produces 501mm. So a 500mm design width center to center.
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Excellent info. Thanks.
Nuxland confirmed that his is also 500mm. Hillhater also posted this:
CIA kart regulation specs are online. And sites like this can be useful…
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Great info. Thanks for sharing this.
Introduction video for my project. More to come!
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Planned episodes:
EP01: Intro - Done!
EP02: A Salt and Battery
EP03: BusBar Mania
EP04: Avoiding Wiring Spagetti
EP05: It’s all about the BMS
EP06: Charge!
EP07: Merry Christmas
EP08: Batteries Included
EP09: Ground Control to Major Tom
EP10: Velocity Control and Cleanup
EP11: First Spin!
EP12: Up in Smoke
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Eh, this one sounds ominous.
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Hopefully JUST the tires… 
Very nice video and very cool project. I am interested in seeing the rest.
Keep up the good work, we are interested in your progress!
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