BBSHD - What does "hot rod" programming mean?

[JPLabs]

If it's not GPS or radar speed, it's just a guess........ Display speeds are about as accurate as display battery capacity.

That's very true. I'll GPS check my speedo. It's probably reading too high.

[CraigAustin]

Clarus - I suspect your 20" wheels are causing the exaggerated speeds. You can adjust it pretty easily (among other things) here: https://www.youtube.com/watch?v=DPTtoLJomI8

[Alpinist]

35.6 mph GPS verified, fastest mile avg. 29.5 mph on 3 mile flat stretch. BBSHD 52V 30A. 700c tires 38mm wide, I doubt I was pedaling since 30 mph is above a cadence I can spin

[gman1971]

Pedaling at that speed is pretty much pointless, no amount of power you can deliver will make any difference when the motor is dumping 3000W...

To get to 36 mph on my upright Cyclone eBike I need close to 1800 W, and to reach top speed of 42 mph it needs basically 3000W. At 30 mph my eBike requires 1200W. The best way to determine what power is required at what speed is to first figure the power at half the desired speed and then multiply that number by 8, that will give you a rough estimate of the power you'll need to get there. For comparison, my trike with some basic aero work needs about 750-800 watts at 30 mph on flat, no wind... and @ 58 mph (tested) requires ~5.2 kW, so to get to 60 mph (those extra 2 mph) will require 1200W more, and a long enough road for it to get there.

G.

[CraigAustin]

Have to disagree Gman. No idea how many watts my BBSHD puts out, but the only way I reach 35mph is by pedaling my @ss off.

[gman1971]

Mine gets to 36 mph effortlessly, but I don't have a BBSHD, I have a Cyclone 3000W running @ 60 amps so that helps. To get to 36 mph my Cycle Analyst reads 1800 something watts... you can disagree, but the numbers are what they are. Which would make perfect sense, assuming that 1500-1600 watts or so coming from the bbshd, so if you can deliver 250 watts or more for a sustained amount of time then its perfectly doable, but you are adding 3 more mph over the 30 something the motor is doing... so at that speed you're not doing much compared to how much the motor is actually doing.

What people also don't keep in mind is that "pedaling your ass off" is different for everyone, I can assure you that your "pedaling your ass off" in terms of wattage is not the same as Miguel Indurain or Alberto Contador... each one has a "pedaling their ass off" power output... so you might as well be very fit. Others can reach 35mph without any electric assists, like those previously mentioned professional TDF cyclist.

G.

[CraigAustin]

Jesus man, take a knee for once. No one doubts your grasp of electric power theory, but there are things you just don't know because you were building model airplanes while some of us were playing sports at a high level. Watching TDF races with color commentary is not the same thing. I appreciate all you contribute here - some of it is truly fascinating - but stay in your lane when it comes to cycling knowledge. The difference between 30 and 35+ is a big one for commuting around here, so pedaling is not pointless at all.

[Mgbguy1]

Thank you, I enjoy this forum a lot of great conversation but, sometimes.......

[gman1971]

Jesus man, take a knee for once. No one doubts your grasp of electric power theory, but there are things you just don't know because you were building model airplanes while some of us were playing sports at a high level. Watching TDF races with color commentary is not the same thing. I appreciate all you contribute here - some of it is truly fascinating - but stay in your lane when it comes to cycling knowledge. The difference between 30 and 35+ is a big one for commuting around here, so pedaling is not pointless at all.

Why would take a knee? I am simply stating my findings while being civilized and not being confrontational, nor calling your findings BS, in fact, if you read carefully I agreed with you that what you're stating is, in fact, doable. Building and flying RC large scale helicopters is not relevant to this matter, so I don't see why you brought it up here, maybe to demerit my response?, while also assuming that I've never done any kind of sports at any higher level? What about 40 meter dash at 3.9 seconds? That was over 20 years ago, and I can probably still take you at a 40 meters dash today... I used to train as a 100 meter sprinter; but regardless, all that stuff is irrelevant to this matter. Old glories don't mean anything as I am not a teenager anymore, nor I actively train beyond the casual ride. But the fact remains that those TDF riders are capable of 415-450 watts output for 1 hour, sustained effort. And probably close to 1700 watts peak for a few seconds. So yeah, to reiterate, 1700 watts IS very relevant to get to 36 mph, but not sustainable. Most normal untrained people are 100-150 watts output, you could be a 250 watts, 350 watts, I don't know, and that makes a huge difference on what you can deliver over a few seconds peak as well. Your bike can also be super aerodynamic, very light and you could be riding aero-bars too... all that makes a huge difference. So without hard data to compare we are simply speculating how much you can peak, how much the motor is doing and therefore not possible to draw any conclusions.

All I know is the data recorded from my Cycle Analyst, which again its not the same as what your case would be; and the power required for my my eBike on "mostly" flat surface to get to 36 mph on my Cyclone 3000W eBike is around 1600-1800 watts... give it a 10% efficiency loss so the motor is putting out about 1400-1600 watts, and another 5% loss at the drivetrain and you have ~1300-1500 watts at the wheel. Then, in contrast to those numbers, the trike is about 800 watts to get to 30 mph, so yeah, the trike is much easier for me to get to 30 mph than it is my eBike.

G.

[CraigAustin]

You like math so you must know Jacobi. Take his advice and always invert. On a normal road bike I can exceed 30 mph on pedal power alone. The BBSHD might get me another 8mph on that bike, so who's doing most of the work? Well you say, that last mph requires much more power than the first 30. True, but then, if the motor gets me to 30+ and I can pedal it up to 38?

Here's another construct: I'm commuting, not racing. My speed comes in bursts (think sprints) to keep up with cars between lights and stop signs. I couldn't pedal that hard for an hour, nobody can, and my battery would last 15 minutes at that pace anyway. Comparisons to tour riders over long distances make no sense.

I get the numbers, no rider can match a motor. I'm just saying think before you write. If I want to know about Cyclones, or how to go 30 mph in northern winters with black ice, I'm coming to you. But there is much you don't know in the world of pedaling your @ss off.

[gman1971]

I spend time thinking my replies, but you just jumped to conclusions before reading my entire post, which btw, it agreed with your findings.

Road bike = very efficient bike, the wattage to get my carbon road bike to 30 is probably 50% less compared to what it takes for my MTB to get to 30 mph, so you're basically arguing with yourself here. I clearly stated that less aero drag = easier to get to 30, also stated from the beginning that what you described was possible but not for sustained periods of times, then you now tell me about bursts? that's what I already stated. Apparently you're now bent on proving me wrong or something.

All motors have a finite powerband... so say your electric motor can deliver say 1500 watts at 90 RPM; and lets assume max motor RPM is 110. So, in order for you to go faster than whatever 1500W of power from motor are doing, you need to pedal above 90 RPM to match the motor RPM, so the moment you spin faster than 90, the motor reduces power b/c at higher RPM the torque drops, and b/c the RPM usually don't grow according to the torque you're dropping then you're losing power from the motor, until it hits redline, at which it will deliver zero power b/c all its power is used just to spin the motor since as there are no external loads applied to the motor shaft (your legs are doing all the work.) So lets say now you're pedaling at 95 cadence now and doing say 200 watts, the motor still is within its max RPM but now its only doing 1350 watts b/c its no longer at the RPM where it was making 1500 watts of power. So you're now doing a combined output of human/motor of 1550 watts, if you keep pushing yourself, the motor reduces power even further, so now you might be doing 1000 watts, at say 105 RPM, the motor power is further reduced down to 700 watts, so combined output of motor/human is now 1700 watts, so you will be going faster, but not 1000 watts of your legs + 1700 of the motor. Say now you start spinning evem faster, faster than what the motor redline and you're delivering 1700 watts, then you're now doing all the work yourself, b/c the motor isn't helping you a bit as you're above its max RPM and the net torque at max RPM is zero (otherwise it will keep spinning higher and higher forever, its called perpetual motion machine, they don't make those yet.) Electric motors are not internal combustion engines that have a flat torque curve across most of the RPM powerband, torque that inevitably falls to zero when you reach max RPM... electric motors deliver all torque at zero RPM, and that torque drops quickly once they get spinning, and how the torque curve drops over RPM depends on a lot of things.

I build nice stuff that works freaking great b/c I am far from stupid, contrary to what you might think. And what was the purpose of bringing the Jacobi algebra lesson here? Any particular reason for that?

Also, I detest math, its just another tool I use to get me to the end results, which is all it matters to me.

Aerodynamics are far more important than anything else, doesn't matter how strong or fit you are, b/c aerodynamics can mean the difference between 500 watts getting you to 15 mph, vs getting you to 50 mph.

G.

[gman1971]

On the pedaling my ass off matter, you don't know what I am capable of so please, have some respect and don't act like a 15 year old.

[Eric Luna]

I have both the bbshd and the cyclone....and for some reason the cyclone has a higher top speed and the power comes on stronger....even when on a battery limiting the power to 30 amps.

I have not figured out why... i think it might be limits in the controller...but its hard to get the bbshd much over 30mph without pedaling your ass off like some other poster said....where as the cyclone can hit 40...somehow an unreachable milestone of the bbshd.

[gman1971]

That would explain a lot of things... and Craig must be really fit too... going over 30 mph if the motor is not doing all the work requires good physical condition. :)

[JayC]

My stock as delivered by Luna BSSHD hit ~33MPH (display read 29.8MPH set to 26" wheels) on flat ground using level 5 PAS. 52V battery driving Eclipse 42T to 11T rear - drunk 175 pound rider (not me) pedaling his ass off on 50 pound bike w/ 29" wheels.

[CraigAustin]

That sounds reasonable. I can get to 37mph on a hybrid, similar set-up and weight, PAS 5, full throttle, sober and pedaling as described.

[Tomas Pesl]

Which part of BBSHD programming do I change to correct this annoyance.
When I go from standing still the power starts slow until it reaches certain speed and then it seems to kick in to “second gear”
It is annoying especially on steep hills.
Thanks for any help.

[xcnick]

Are you pedaling or just throttle alone?

[JPLabs]

Which part of BBSHD programming do I change to correct this annoyance.
When I go from standing still the power starts slow until it reaches certain speed and then it seems to kick in to “second gear”
It is annoying especially on steep hills.
Thanks for any help.

Thomas,

My bike does the same on PAS, and I've tried a whole bunch of program changes, but never completely eliminated it. The best I've done is to set my currents high vs speed limit, and set 'keep current' low. I think my 'keep current' is at 15% now. I rarely notice the '2-speed behavior' now, but sometimes I do, and I now think there are actually two different realms, where this happens. Low cadence, and higher cadence, with different causes.

Here's what I'm thinking...see if it could fit what you are experiencing. Especially the first, 'Low Cadence', description.

-----

Low Cadence 1-2 shifts (this mode happens when coming up to speed from a stop, or riding at-speed in too high a gear):

• If I really lug it, with very low cadence, I get the 1-2 shift pretty consistently.
  • It seems like the PAS system will limit current, below the user-programmed level, at very low cadence, probably for motor protection.
  • Then, once cadence picks up, the limiting turns off, and you get full programmed current.

So, the bike increases current in a sharp step, instead of gradually, as cadence increases. Feels like a shift.

I am not completely sure about it, but my own BBSHD seems to do it, so I think this explanation fits the 'lower cadences' 1-2 shift symptom. I can observe this with any programming I've recently tried; it seems very consistent, with high- or low-power programs.

I don't think this cause is programming-dependent.

--

Higher Cadence 1-2 shifts (this mode can happen at whatever cadence limit is set for a given PAS level):
From my experience, I think the '1-2' shift also seems to happen when the PAS current is lower than the 'keep current' for given operating conditions, when the control transitions to 'keep current' control. I observed this more through program changes and effects, rather than by just riding the bike on a given program setting, as for the low cadence condition. Here's what I think could be happening:

• There are two different current-control modes in the controller: PAS, and Keep Current.
  • I'm NOT sure if 'keep current' applies all the time, or only above Speed Limit, or if current is a calculation involving both, all the time.
  • If 'keep current' applies all the time, or is 'blended' continuously, then the below doesn't fit.
    • The bike runs on lower power per PAS programming, until the speed limit is reached for that PAS level. PAS power isn't called for above set speed, so it defaults to 'keep current' after speed is reached.
      • If the PAS current setting is relatively high (for example, 20A current setting) and the motor load is low, then only a low percentage of max current is needed. Say, 5A out of 20A limit for that PAS level. 20%.
      • This is "1st gear".
    • Once speed limit is reached, it switches to "keep current'.
      • If Keep current is at, for example, 50%, then the controller delivers 20A * 50% = 10A.
      • That's twice the current of the PAS setting. "2nd gear".

Since it depends upon the PAS current, speed, and 'keep current' settings, this 2nd cause would be program-dependent.

I'm not sure about all this yet, and I recall that AZguy had some different thoughts about it the last time we discussed this, but I've thought about it more and changed my own interpretation of the 1-2 shift, per above.

What do you guys think?

Thomas, if you don't think this fits, what is different in what you experience?