El_Steak
10 kW
A lot of the questions I see from new e-bikers revolve around how big a motor, battery and controller they need for their commute. In an effort to help them in their decision, I recorded data on 6 different commutes using different speed settings on my 3-speed switch (I reprogrammed it a few times for the tests).
Theorically, if you could ride full throttle all the time, a bike with a top speed of 80km/h should get you to your destination twice as fast as a bike with a 40km/h top speed. However, in a real life commute in an urban area you have to deal with pot-holes, bike paths, traffic, pedestrians, school zones, etc. and you can't ride at 80km/h all the time. So the net reduction of your total commute time on a super fast bike is not as important as some would expect.
I used the same bike, motor (9c), controller (18fets/100A) and battery (88.8V 15ah – 24s3pLipo) for all tests (except the pedal only test for which I used a normal hybrid bike). I only changed the top speed selection on the 3 speed switch to simulate a lower power bike.
The commute is 28.2km total (to work and back home) and includes hills, bike paths, traffic, some sidewalk action where I have no choice and plenty of pot-holes. I didn’t take the exact same road on my 48km/h and over commutes as the higher speeds allowed me to ride in traffic and avoid some slower bike paths.
You can see in the graph below the diminishing effect of top speed increases on my total commute time. I also plotted my power consumption on each ride so you can get an idea of how much battery capacity you need to be able to ride the same distance at various speeds. High speeds really eat up the watts!
Conclusion?
If your main interest is commuting and you want to keep to costs and complexity low, a 48V setup with a top speed around 50km/h is a pretty solid combination. You can use standard e-bike components, a reasonable size battery and don't have to worry too much about overheating, blown fets, broken spokes, and the likes.
That being said, 50kph is pretty boring when you're used to 100V 100A... my 3-speed switch is back to 100%
All the numbers:
-Power @top spd is the approximate power used when rolling at top speed on the flat
-Peak power is the approximate peak power used when climbing the steppest hill on the ride at full throttle
-Max temp is the maximum temp measured inside the hub motor
-I measured power consumption in watt/hour as I find Ah can be confusing for some. To get a pack's capacity in watt/hour, just multiply the nominal voltage by the rated Ah. For example, my 88.8V 15ah pack has a capacity of 1332wh. A Ping 48V 15ah would have 720wh
-Also note that my controller has a 100A limit, so on a "standard 48V 20A" controller, you would use less power (but would also have less fun).
Theorically, if you could ride full throttle all the time, a bike with a top speed of 80km/h should get you to your destination twice as fast as a bike with a 40km/h top speed. However, in a real life commute in an urban area you have to deal with pot-holes, bike paths, traffic, pedestrians, school zones, etc. and you can't ride at 80km/h all the time. So the net reduction of your total commute time on a super fast bike is not as important as some would expect.
I used the same bike, motor (9c), controller (18fets/100A) and battery (88.8V 15ah – 24s3pLipo) for all tests (except the pedal only test for which I used a normal hybrid bike). I only changed the top speed selection on the 3 speed switch to simulate a lower power bike.
The commute is 28.2km total (to work and back home) and includes hills, bike paths, traffic, some sidewalk action where I have no choice and plenty of pot-holes. I didn’t take the exact same road on my 48km/h and over commutes as the higher speeds allowed me to ride in traffic and avoid some slower bike paths.
You can see in the graph below the diminishing effect of top speed increases on my total commute time. I also plotted my power consumption on each ride so you can get an idea of how much battery capacity you need to be able to ride the same distance at various speeds. High speeds really eat up the watts!
Conclusion?
If your main interest is commuting and you want to keep to costs and complexity low, a 48V setup with a top speed around 50km/h is a pretty solid combination. You can use standard e-bike components, a reasonable size battery and don't have to worry too much about overheating, blown fets, broken spokes, and the likes.
That being said, 50kph is pretty boring when you're used to 100V 100A... my 3-speed switch is back to 100%
All the numbers:
Code:
Time AvgS Wh used Wh/km Power Power End Max
kph @top spd Peak Volt Temp
--------------------------------------------------------------------------------
Pedal only : 89m00s 19 N/A N/A N/A N/A N/A N/A
Max 36kph with pedal: 55m36s 30.5 402.19 14.2 450w 1500w 94.1V 50C
Max 36kph no pedal : 59m34s 28.4 482.85 17.1 550w 1700w 93.1V 60C
Max 50kph no pedal : 45m06s 37.4 675.89 24.0 1200w 3500w 91.5v 80C
Max 60kph no pedal : 43m00s 39.2 821.43 29.2 1900w 5000w 90.7v 110C
Max 75kph no pedal : 40m30s 41.7 951.19 33.8 2800w 6000w 89.9v 130C-Power @top spd is the approximate power used when rolling at top speed on the flat
-Peak power is the approximate peak power used when climbing the steppest hill on the ride at full throttle
-Max temp is the maximum temp measured inside the hub motor
-I measured power consumption in watt/hour as I find Ah can be confusing for some. To get a pack's capacity in watt/hour, just multiply the nominal voltage by the rated Ah. For example, my 88.8V 15ah pack has a capacity of 1332wh. A Ping 48V 15ah would have 720wh
-Also note that my controller has a 100A limit, so on a "standard 48V 20A" controller, you would use less power (but would also have less fun).
