Power consumption sweet spot

Alexopp

10 mW
Joined
Nov 19, 2020
Messages
26
I have a road bike with Mxus 19R 1000w nominal rear hub motor with a 52V battery. I followed ca guy on YT that continues to say that mid drives are much more effective at low speed because of the gearing range. My motor has a reduction gear with a ratio of 1:5.8 with a 28 inch wheel and peaks at 55 kmph top speed with a full battery. I use my bike for long flat trips on asphalt. What speed should I keep constant in order to travel as long as possible with one battery? Thanks in advance!
 
When you've been riding for a while it will be VERY clear speed kills battery mileage.

The answer to your question will likely be the lower the better, down to something under 8-10 mph.
 
The sweet spot is as slow as you can stand to ride and still feel like you're on an e-bike. That's around 18mph for me, but if you can ride slower than that, you can get more range, especially if you have all the time in the world to get there.
 
Thanks for the answers! I usually keep a steady 20 mph when I travel. What is your opinion on swtiching from my hub drive to a mid drive in my case? Will it consume less because of gear adjustment? Sry but that grin simulator beats me.
 
Alexopp said:
Thanks for the answers! I usually keep a steady 20 mph when I travel. What is your opinion on swtiching from my hub drive to a mid drive in my case?
Mid drive shines on hills, because you can keep the motor at a more efficient operating point. If you are mainly riding flats, you won't see a significant improvement.
 
Alexopp said:
Thanks for the answers! I usually keep a steady 20 mph when I travel. What is your opinion on swtiching from my hub drive to a mid drive in my case? Will it consume less because of gear adjustment? Sry but that grin simulator beats me.

I got a little more range per watt-hour of battery with BBS02 than with a hub motor. My habit was keeping the bike in the lowest gear that I could still pedal along with the motor at any given time.

A mid drive allows you the option of keeping the motor in an inefficient speed range all the time, too. That's something to be aware of if you're concerned about range.

If your riding is all flat and paved, then there's little reason other than high winds to be able to vary your motor gear ratio. The most effective technique for conserving energy (assuming a fixed cruising speed that you choose) would be to use a controller with PAS and selectable assist levels, then using the lowest assist level that will sustain your cruising speed. The harder you pedal, the better.
 
Great answers! Thanks you all! I have a PAS assist controller, I use the 300W or 500W assist level depending on inclination, I noticed that when I climb a hill, the motor is more efficient if I keep the bike over like 10 mph, in this way it has higher rpms and better gear advantage, if I sink below 10 mph I`ll just use more power. But no worries, my whole bike project was focused on fast long asphalt touring, the motor has lots of power, even 1 KW is still peanuts for this motor, also I carry with me two 800Wh batteries and two 4A chargers.

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Snow is pretty bad for range but good for motor cooling :wink:

If you have a meter that measures motor power or current, you can instantly see the results of speed, hills, snow, etc.
As Chalo points out, if you pedal hard enough, your range will be unlimited. When you have hills or stiff head winds, things change and gearing becomes much more important. Keeping the motor in the most efficient range is good, but not nearly as important as minimizing power requirements.
 
I think a mid drive would help if I climb hills at a low speed but I usually climb at high speeds and on good roads, so the gearing of the hub motor almost always fits my speed. No hill can slow down my beast.
 
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