Which scenario drains the most battery?

Volusia25

Pedelecer
Apr 21, 2017
243
106
33
leicester
So there's a steep hill coming up.

1. You put it on a low assist (1-2) and get pedalling, but at this assist level, even with pedalling you can't get the bike up to 15mph so the motor is working fully until you reach the peak.

2. You put it on the highest assist, with the same pedalling effort (or slightly less) and the bike reaches 15mph (or whatever you have the limiter set at for illegal bikes)

Which would drain more battery and reduce overall range from one charge?
 

Woosh

Trade Member
May 19, 2012
19,529
16,466
Southend on Sea
wooshbikes.co.uk
most likely scenario 2, but the difference would be small at equal user contribution.
Higher assist will almost always produce higher acceleration thus burning a bit more.
 
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Paul smith

Pedelecer
Mar 26, 2016
249
198
Who cares...do you really go into it that deep as your peddling up steepest hills..ooh.. am I doing 15 an half miles an hour now??.......lowest gear..highest setting....way to go..
 
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soundwave

Esteemed Pedelecer
May 23, 2015
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Deleted member 4366

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Most likely the second scenario will use the least battery because the motor will be running more efficiently. It will consume battery charge more quickly, but it won't be doing it for as long. This assumes that climbing speed is not too fast - say less than 15 mph - so that air resistance isn't a big factor.
 
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Croxden

Esteemed Pedelecer
Jan 26, 2013
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Woosh

Trade Member
May 19, 2012
19,529
16,466
Southend on Sea
wooshbikes.co.uk
Most likely the second scenario will use the least battery because the motor will be running more efficiently. It will consume battery charge more quickly, but it won't be doing it for as long. This assumes that climbing speed is not too fast - say less than 15 mph - so that air resistance isn't a big factor.
the calculation of the required energy to accelerate the bike to 15mph is similar to calculating the critical damping in physics. The smoother the acceleration, the less waste you are going to get. Higher assist level will likely produce more oscillations, therefore is less energy efficient.
 

Volusia25

Pedelecer
Apr 21, 2017
243
106
33
leicester
Most likely the second scenario will use the least battery because the motor will be running more efficiently. It will consume battery charge more quickly, but it won't be doing it for as long. This assumes that climbing speed is not too fast - say less than 15 mph - so that air resistance isn't a big factor.
Seems to have made little to no difference on my way home yesterday. Just my usual ride, the way home is always mainly up hill. I struggled on assist 2 on a mid charged battery and it wasn't helping much, thighs starting to burn after about half an hour of doing this. Said sod it and used assist 5 and throttle for the remaining 5 or so miles and got home having not saved any more power than if I did the whole return trip on assist 3-5
 
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Deleted member 4366

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the calculation of the required energy to accelerate the bike to 15mph is similar to calculating the critical damping in physics. The smoother the acceleration, the less waste you are going to get. Higher assist level will likely produce more oscillations, therefore is less energy efficient.
Acceleration would be negative going up a hill, so does that mean that your conclusion from your theory is the wrong way round?
 

Woosh

Trade Member
May 19, 2012
19,529
16,466
Southend on Sea
wooshbikes.co.uk
Acceleration would be negative going up a hill, so does that mean that your conclusion from your theory is the wrong way round?
I don't think the gradient would change the basic calculation as long as the motor is required to provide assistance. You integrate the battery usage over the distance, oscillations will automatically add to waste.
 

Euphony

Finding my (electric) wheels
Jun 22, 2017
7
2
62
Scotland
Were ever yous think yous where going with this post, I think the pacific point off it has bin lost on the way. It could of bin so different........never mind - there their they're......
And the only thing I loose any sleep over is a wheel coming lose.;)
 
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GLJoe

Esteemed Pedelecer
May 21, 2017
852
407
UK
So there's a steep hill coming up.

1. You put it on a low assist (1-2)
..
2. You put it on the highest assist
A couple of technical questions if I may:

1. What EXACTLY does changing the assist level do (in terms of what gets delivered to the motor)?

2. Does changing the assist level shift the zone of maximum efficiency of the motor (and thus change the heating losses at a given motor rotation speed)

??
 
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