Arlo1 wrote:I have build a dyno. Seen here http://www.youtube.com/watch?v=XdjQ445WoJw and as a mater of fact it will work for low power ebikes.
Nice work, though as you mention a brake dyno would likely be better for the ebike. We woul dlike the measured for torque/power under sustained load.
As for an ebike like mine a motorcycle dyno would likely work. It is a matter of what type of dyno it is what we want to test for acceleration is inertia dynos. But if we could vary the load it would help to test efficentcies at different levels like simulate different hills. So a brake dyno is best for this other wise It is possible to add weights to my inertia dyno as well. As for the program I have and the dyno mesureing equipement it is for inertia. But for acurate variable load tests one could use a brake mounted to a old cheap tourque wrench to hold it at a certain speed and increase load and the tourque wrench will tell you the tourqe!
Not a bad idea. I hadn't thought of using an external static torque measure and a brake. An electric brake may as you say below, be smoother than a mechanical. A lever and a scale could be more accurate than a torque wrench.
Arlo1 wrote:As for most motorcycle dynos dynojet ect. alot of them have eddy brakes so they are a light drum that spins up easy and to add load for higher power bikes they use the eddy brake at a load percentage.
I still wonder if a regular dyno can accurately measure in the 10 or even 100w range. Given that most are designed to hundreds of hp, it would mean they have 0.1-0.01% accuracy. That would be better than my multimeter!