Yea finding an esc that does enough amps, they all do more volts because it’s impractical. But other than being practica and talking only of electrical efficiency in the motor and esc, if he were limited to an 80kv hub motor, and he wanted to also use 8 volts, and wanted to be as efficient as possible. …there’s a simplified facet of efficiency and how u want to be riding as close to around 85% of the "no-load "speed. There maybe be other losses in the wiring if it weren’t fat but for the motor ideally I think it would be low voltage…in at least this one regard. But overall I could be totally wrong and at that high amperage the losses in the esc and maybe even the motor would be greater. Any naysayers?
But practical is what is needed here…no need to invent new stuff… Just need to apply the available products to his needs…there is plenty of expertise here that can get him to feasible solution that is simple and cost effective
Do you have a basic drawing of how you want this to look?
That was a mistake in my math and understanding of how KV ratings work. Suggestions are welcome.
Keep it simple…
You biggest issue and concern is being able to keep it at a low speed, with lots of torque
The vesc with @Ackmaniac program should be able to manage the motor power and speed … even if you had a simple 10s lipo set up in a pouch … even at that high a voltage you can get it to creep along (use sensored motor set up)
So i guess what you need is something that has a decent amount of torgue at very low speeds. Just to keep it relatively cheap and easy i think the best idea would be to have big wheels with a very high gearing.
A 6S LiPo would be good because it is easy to get and chargers are also cheap. Then go with sensored motors with as low kv as possible.
If you have later on a gearing of 12/40 and a 140kv motor you will reach 6 km/h (4 mph) at around 8V. With a 6S battery this will be at 34% duty cycle. All in all this should be more than enough.
Then you can attach a thumb remote to the frame so that your father can control it. And by fine tuning it should be possible for him to control it to his needs. The bigger problem i see is that when all of this can roll then it won’t give him much support when he looses balance. And i think that is the main reason for a walker.
Wheels: 97 mm blank wheels on ebay (25$ only USA) Motor: 140kv Evolve motors from china (50$ a peace) Battery: 6S LiPo (? ebay) Charger: IMax B6 (25$ for a clone)
[quote=“mfidelman1, post:24, topic:23576”] of [/quote] @mfidelman1 what is this thing your planning to make. No drawing.
Damn my writing is unreadable above. And probably wrong besides. What are the losses in the esc vs motor ?? In my experience no over temp on the vec just overheat motors. The losses in the vec are very small I think.
take a look at https://www.youtube.com/watch?v=1FSWf8vG0kI&t=18s333 at around 1:34
now that was built from a canabalized rascal scooter, but the same idea - what I haven’t decided yet (and will probably determine from experimentation) is whether to a. power the front wheels (e.g., using scooter type wheel motors) b. put an e-skateboard truck underneath the platform (with your kind of hub motors)
The choice is coming down more to one of parts availability.
Watched the video. I think the possibility of using a skate truck if it were already there alway, part of the walker, in front, and a caster wheel at either side. A four wheeler that worked kind of like a tripod is what I like. It would be nice if u could weld a frame. that could take a while. I have no idea how to do it but could be awesome. Grandpas speeding all over with overpowered silent vecs n hub motors on Harley skate choppers.
Well… I have visions of grandmas racing the things, but… 
As to construction. My dad really wants to convert the walker he already has - basically clamp on a platform that holds all the power components, mounted on a hinge at the front, so it can fold up the same way the current walker does. Skate truck(s) and motors would be on the bottom of the platform.
My concerns keep coming back to battery capacity and heat, when running the motors at low revs, and low efficiency.