Powertrain recommendations for a QS 273 powered faired trike

[tymotors]

Hello everyone,

I have been thinking about building a 2 seater (inline seating to reduce frontal area) velomobile style tadpole trike, but with a massive hub motor to hit highway speeds with ease for extended periods. I estimate that it will weigh about 700lbs with 2 people in it. Target power is ~30kw, with 15kwh of 24s LFP cells. I plan on building the frame and fairing from scratch since velomobiles are very expensive, and I have considerably more time than money right now. This will strictly be a road vehicle.

So with the basics out of the way, here are some of the specifics I have been mulling over for quite some time now:

I would like to use a 13 inch qs 273 motor to get the magnets as close as possible to the road for efficiency and power benefits (best mechanical advantage). It seems like an appropriate choice since the motor will only be pushed on steep uphills and quick acceleration, for cruising it will be very under stressed due to the excellent aerodynamic efficiency of the planned vehicle. From playing around in the motor simulator, it seems that the motor will be more than capable of climbing 30% grades at decent speeds if given enough juice. For now, I am ok with this not being a performance vehicle, but I do need it to climb hills without overheating.

This brings me to my questions for you all:

For those of you with experience dealing with QS, will I be able to get a motor with a KV of about 25-27? This is required for my speed requirements (65-70 mph up a 6% grade). I am not opposed to winding a motor myself, but avoiding that would be nice.

I have looked at getting an ASI BAC 8000 to be able to pump enough phase current through such a fast wound motor, however in light of Nucular releasing their new 24F controller, it seems that 500 phase amps will do according to the motor simulator. I would love to hear your experiences with both controllers. I am leaning towards the 24F since it is so much cheaper (ASI keeps raising the price of their eval kits). I am fairly opposed to any Chinese power electronics in this build since I have had bad experiences with them in the past, but I could be convinced otherwise. My requirements for a controller are programmable FOC with variable regen braking.

I haven't even started thinking about suspension and whatnot, but I will definitely need advice for that as well.

Budget is around 10k US.

Thank you in advance for your help

 

[amberwolf]

For those of you with experience dealing with QS, will I be able to get a motor with a KV of about 25-27? This is required for my speed requirements (65-70 mph up a 6% grade). I am not opposed to winding a motor myself, but avoiding that would be nice.

If it is possible to wind a motor a certain way, QS will probably do it for you; you just have to ask them. They have a thread in the for sale section that they respond to if you can't reach them via their main website.

If you find you must rewind it yourself, there is an ongoing thread about doing this

Rewinding a QS 273 motor

Hello everyone, A good friend of mine unfortunately fried his motor recently. It looks like one of the phase partially melted down. He dropped the motor off to my place yesterday and now I'm trying to see if I can rewire it. That would be my first time attempting this task, so I thought I'd...

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If you find it's not possible to get the motor RPM you want at the voltage you want to use, you can either up the voltage, or you can use an in-frame motor chain-driving (or belt, etc) the wheel.

I have looked at getting an ASI BAC 8000 to be able to pump enough phase current through such a fast wound motor, however in light of Nucular releasing their new 24F controller, it seems that 500 phase amps will do according to the motor simulator. I would love to hear your experiences with both controllers. I am leaning towards the 24F since it is so much cheaper (ASI keeps raising the price of their eval kits). I am fairly opposed to any Chinese power electronics in this build since I have had bad experiences with them in the past, but I could be convinced otherwise. My requirements for a controller are programmable FOC with variable regen braking.

One option for such a controller is to use a powerstage from a large EV controller and disconnect it's brain, then use Leboswki's chip or others (Openinverter, VESC, etc) to run that powerstage. There's a few threads about that, such as Marcexec's presently going complete how-to thread using a Honda IMA controller for the powerstage, and a Kiwifiat-built Lebowski brain board to run it. Programming is all done via a serial terminal; the entire program is on the brain board so it is literally programmable from any device with a serial port, even an ancient "dumb terminal".

Yet another Lebowski + Honda IMA inverter & step-by-step

Intro: kiwifiat challenged me with a SMD Lebowski board (thanks for the trust & funding from coleeasterling as well!) to integrate into the Honda IMA inverter and test on my motorbike as I have the Enertrac MHM 10kW hub motor and run 36S Nissan Leaf modules, so plenty to play with. Here's the...

endless-sphere.com

IIRC one issue with ASI is that you require codes to get into their software to do anything with it, and if they "turn off" the code then you can't run the setup software to program your controller anymore. If they don't do this kind of software access control anymore that's good, but you'd have to find out how they work this.