I’m thinking it would be nice to collect some real world efficiency data. We have many different drives in the community. I propose we do a “motor efficiency challenge”. You’ll do a normalized run and report your consumption to a Google Form. We’ll then compile the data and make some stats. We just need to figure out what the “normalized run” should look like. How about something like this:
- choose a route with a smooth surface, as flat as possible
- at least 1 km distance; you should know the total distance exactly
- start and finish at the same location (either do a circuit or go back and forth)
- do 3 runs:
- 20 km/h constant speed
- 30 km/h constant speed
- 40 km/h constant speed
- measure the consumed Wh for each run
The values to report then could be (examples in italics; bold is what I think are the critical pieces of info):
- measured consumption
- 20 km/h: 13 Wh/km
- 30 km/h: 15 Wh/km
- 40 km/h: 17 Wh/km - motor
- Maytech 6355, sensored, 190 kv, 14 poles
- Turnigy Aerodrive SK3 6374, unsensored, 149 kv, 14 poles
- TB DD motor, 6374, sensored, 72 kv, 28 poles - wheels
- black TB thane 110mm
- Superstar Hubs, 165mm pneumatics, 70psi
- Bergmeister Hubs, 141mm pneumatics, 60psi - drive:
- belt drive, 14:62 gear ratio, 15mm belts, 1WD
- Avio MK2 gear drive, 13:43 gear ratio, 4WD
- TB direct drive, 1:1 gear ratio, 2WD - battery pack:
- 10S5P Samsung 30Q - loaded weight (rider + gear + board):
- 90 kg - outside temperature:
- 15 Celsius
Is that a good idea? Any suggestions on the “normalized run” or the type of data to collect? I believe that for the data to be useful, it’s necessary to make some trade-offs between the level of detail and the density of the data, such that there’s a chance to do reasonable grouping and averaging.