jimcroisdale
10 mW
Hi all,
I'm part of a team that's designing an electric single seater "efficiency" style racer - 3 wheel reverse trike formation, super low drag body - you know the type. There are many final technical decisions/choices yet to be made, but we have a lot of solutions "circling the drain", ready to fall into place.
Our car will need to be able to run at a constant speed of around 35mph, using around 650w. Battery pack will vary from 94v at its highest (right off the charger), quickly dropping to 86v at first use, and then gradually tapering off to a minimum of around 83v.
Wheel speed for 35mph will be approx 500rpm, so low kv motors are needed, to avoid reductions ratios higher than 10:1. We will most likely be using spur/pinion gear drive, as it is most efficient, and ratios can be easily adjusted.
We reckon 15Nm at the wheel will do it.
There are some very expensive solutions out there (motors that the big solar car teams use) but they are waaaaay out of our budget. Our research has led us to the outrunner RC motors of Astro Flight, Neumotor, Plettenberg and more - and they look to have some good fractional horsepower options with high efficiency, but we're wondering if there's anything else out there that we're missing. We're aiming/hoping for 92%+ - seemingly not easy at such low speeds.
We're also going to need an efficient (and bulletproof!) controller too!
Thanks for reading - I welcome your thoughts!
Jim
I'm part of a team that's designing an electric single seater "efficiency" style racer - 3 wheel reverse trike formation, super low drag body - you know the type. There are many final technical decisions/choices yet to be made, but we have a lot of solutions "circling the drain", ready to fall into place.
Our car will need to be able to run at a constant speed of around 35mph, using around 650w. Battery pack will vary from 94v at its highest (right off the charger), quickly dropping to 86v at first use, and then gradually tapering off to a minimum of around 83v.
Wheel speed for 35mph will be approx 500rpm, so low kv motors are needed, to avoid reductions ratios higher than 10:1. We will most likely be using spur/pinion gear drive, as it is most efficient, and ratios can be easily adjusted.
We reckon 15Nm at the wheel will do it.
There are some very expensive solutions out there (motors that the big solar car teams use) but they are waaaaay out of our budget. Our research has led us to the outrunner RC motors of Astro Flight, Neumotor, Plettenberg and more - and they look to have some good fractional horsepower options with high efficiency, but we're wondering if there's anything else out there that we're missing. We're aiming/hoping for 92%+ - seemingly not easy at such low speeds.
We're also going to need an efficient (and bulletproof!) controller too!
Thanks for reading - I welcome your thoughts!
Jim