Torque assist or using throttle, which is more efficient?

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craneplaneguy
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Torque assist or using throttle, which is more efficient?

Post by craneplaneguy » Nov 26, 2017 1:10 pm

Riding 20 miles of trail yesterday on my BBSHD/ Sturgis Bullet fatbike combo, with my PAS (cadence sensed) turned as usual to ZERO, and using my thumb throttle as needed to augment my always moving legs, with a buddy who is on his Haibike and it's torque sensing assist/no throttle. He is convinced his ride is more efficient, and we bat the subject around all the time when riding, when not gasping for breath. I insist I only use throttle when needed, and as little as possible, so how can that be less efficient?

On one stretch of more or less rolling terrain, I realized that for the last several hundred yards I had been pedaling, with zero throttle. He, meanwhile, while also pedaling of course, had to have been using some juice, right? He only moves when he pedals, but he also uses juice every time he pushes down the pedals. When I pointed this out, he said he can turn his off and use zero juice, (but in practice he doesn't do that routinely or often) yeah I get that, and I do so several times a minute, I call it "backing off on the throttle." But I don't have to kill my entire system and then reboot it, I think of my throttle as a infinitely variable PAS, one that won't help me, and use juice, except for when and how I command it.

You'd think we could work this out by comparing at the end of the ride our batteries SOC, but his display doesn't show volts like mine, plus he has no idea what percent of capacity his Haibike supplied charger goes to, and it also a different voltage then mine, plus I have a larger AH battery, so it get's complicated quick. We did figure out that I ended up with more juice and had more range left, but that would be expected with my larger capacity. I find it interesting that the riders with only torque sensing and no throttle systems somehow think having a throttle means you are less efficient, I don't buy it, and would appreciate any thoughts on the subject.

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Re: Torque assist or using throttle, which is more efficient?

Post by marvak » Nov 26, 2017 1:24 pm

Interesting, well you can set your torque sensor to certain parameters, so motor kicks in when you need it. For example starting from stop, or on other end using it at top speed. So it works automatic how you want it, and hand throttle is manual control over that.

Other then not having to use throttle with tumb, dont see many difference in efficiency.

Anyway torque sensoring bikes need better shifters between amount of extra power from motor. If you had nice design to shift between 4 "gears", say 0, 40,90,130,200% extra watts, then you can very efficienctly control amount of juicy, without having to have throttle

Edit: maybe this will help, same question, about cars
https://auto.howstuffworks.com/fuel-eff ... omatic.htm

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Re: Torque assist or using throttle, which is more efficient?

Post by dustNbone » Nov 26, 2017 1:56 pm

It's only more efficient if you can't behave yourself with the throttle. Being able to optimally set your ratio of leg to motor power in real time seems like the most efficient possible scenario to me.

But a proper comparison of efficiency would need energy meters (measuring Wh) on both bikes, and the 2 bikes being as similar to one another (at least in terms of rolling resistance) as possible. Similar tires sizes/pressures anyway.

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Re: Torque assist or using throttle, which is more efficient?

Post by marvak » Nov 26, 2017 2:22 pm

Probably, for me requiring to have tumb throttle is not worth it

Although I am kind talking about same thing with throttle for amount extra watts. Those round shifters that you twist and turn. That way you dont have to actually hold down the throttle. And the motor stops when you stop pedaling

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Re: Torque assist or using throttle, which is more efficient?

Post by dogman dan » Nov 27, 2017 7:52 am

Any riding without power is not really more efficient, but does indeed save the watt hours for later use. I don't like to call this a more efficient ride, but rather riding more efficient. Splitting a hair, but the two things are very different. It's quite possible for a person on a 3000w dd motor to ride more efficient than a person on a 200w mid drive. Unlikely as hell, but still possible.

But assuming you both pedal the same, and use some power, and your throttle does not allow more than his, you'd only get different range based on how hard you pedal, how much you weigh, and so on.

Definitely easier to keep riding more efficient, at a low power level with the PAS type. My hand at least, always wants to creep up and allow me to pedal with less effort.

One thing I'd like to try someday for dirt, a PAS mid drive, but with a throttle that is only a push button, to give full power when you need it for 2 seconds.

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Re: Torque assist or using throttle, which is more efficient?

Post by MadRhino » Nov 27, 2017 9:37 am

Unless it has a very good torque sensor system, I hate riding a PAS.

Efficiency can be better or worse with a throttle, as you wish, since you have the control in your hand.
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Re: Torque assist or using throttle, which is more efficient?

Post by Alan B » Nov 27, 2017 10:00 am

Spending two or three times on the Haibike is a bit of inefficiency with respect to funding. :)

What do we mean by efficiency here - range per battery capacity? That's really not a very useful thing, just limit your drive to zero power and your range is infinite.

A torque throttle gives greater control precision than a torque PAS. With throttle you can decide by the millisecond how much battery to use, and how hard to pedal, and what gear to be in. The amount of each is totally under your control in real time. This gives you the option to be efficient or to motor up the trail or road and give your legs a rest, moment by moment.

The torque multiplying drives don't have that fine control. The ratio between human power and battery power is not that easy to change on the fly, moment by moment. They are developing different control algorithms to try to automatically determine the right mixture, but like any automatic system the results vary and aren't right for every situation. It is kind of like the manual versus automatic transmission debate.

If you take a spill and injure your knee or ankle, which ebike will get you home? I've been in that position, and the throttle carried the day. PAS would have been a major failure.

So at the end of the ride, people need to respect other's choices. What works best for you is what works best for you. You should be able to choose, and not have some law (like the ones in California which require PAS over 20 mph) determine which you should use. Torque PAS gives your thumb a nice rest, but it is expensive and complicated to build into the bike. Torque throttles are much cheaper, simpler and more reliable to implement in the motor controller. But what we have mostly is PWM throttle which is not the best throttle control. The best system would have all or most of the options available and let the rider decide what to use. Limiting the rider's choices is taking away freedom. Why would someone want to do that? Reducing freedom of choice is not the American way.

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Re: Torque assist or using throttle, which is more efficient?

Post by craneplaneguy » Nov 27, 2017 11:06 am

My thoughts exactly...... I pretty much knew the responses would be about what I've seen so far, now, the next time I'm riding with this guy and we start this discussion again, I'll pull up this thread (he doesn't hang out here) and show it to him, it STILL won't change his mind, he's convinced he's right, but that's OK at least I'll know I made my best effort to convince him otherwise! He's coming up on 400,000' of vert according to his Strava app for this season, being retired and riding every day, so I'll cut him some slack. :lol:

My left hand thumb throttle, on all three of my bikes (2 BBSHD's and 1 BBSO2) is situated so I can easily keep a firm grip on the bars while also maintaining any setting I feel the need for, while still being able to romp on it when needed. It's not any kind of hardship or inconvenience, and real stealthy (as if I cared, where I ride) a bit to my surprise from I first started riding e bikes, maybe I just have my thumb trained, but I strongly feel a thumb throttle gives me the best of all worlds, or at least the best way to use the least amount of power. I like being directly involved in the decision process as to how much power to use! Also,good point on the "still being able to get home if unable to pedal" thing, I never thought of that. Also, when the home barn is in sight, or whenever I know for sure the ride is nearly over and range is a non issue, it's great fun to wrap things up, especially after the rides usual earlier great restraint, with a boatload of throttle, pop a few wheelies etc.!

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Re: Torque assist or using throttle, which is more efficient?

Post by billvon » Nov 27, 2017 12:21 pm

craneplaneguy wrote:
Nov 27, 2017 11:06 am
My thoughts exactly...... I pretty much knew the responses would be about what I've seen so far, now, the next time I'm riding with this guy and we start this discussion again, I'll pull up this thread (he doesn't hang out here) and show it to him, it STILL won't change his mind, he's convinced he's right
He may be right. If torque assist gets him pedaling more, then for him torque assist IS more efficient.
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Re: Torque assist or using throttle, which is more efficient?

Post by wturber » Nov 27, 2017 1:10 pm

craneplaneguy wrote:
Nov 27, 2017 11:06 am
I'll pull up this thread (he doesn't hang out here) and show it to him, it STILL won't change his mind, he's convinced he's right, but that's OK at least I'll know I made my best effort to convince him otherwise!
Why argue the point? Just ask him to demonstrate/prove it. He won't and/or can't. End of issue. Back to riding...

My PAS system is from the KT controller and I do kinda like it, but for best results, I have to fine tune it on the fly by changing PAS levels - which is a simple button press on my LCD display - and also use the throttle. The main benefit is less manual input.

'PAS 2 is good for flats, moderate downhills, when I have tailwinds or when I don't care to go past 20 mph and/or am looking to conserve battery.
'PAS 3 is good for moderate uphills, headwinds and when I'm more interested in travelling a bit faster and less concerned about battery.
'PAS 4 is good for just a couple of long medium uphill sections on a busy road that I like to get off of as soon as possible.
I consider PAS 1 useless because I never go that slow and PAS 5 useless because I can just twist the throttle to full if I need that much power. So, I'm in 2 or 3 most of the time and I augment their input by using the manual twist throttle.
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Re: Torque assist or using throttle, which is more efficient?

Post by Triketech » Nov 27, 2017 11:42 pm

BBSHD uses cadence PAS not torque PAS. Very different beasts when it comes to efficiency gains.

When I was testing the BBS02 I found a slight gain in efficiency with the thumb throttle on a trike. The Cadence PAS, no matter how I configured the settings was basically a 5 speed motor. Maybe better for flatland riding, but not so efficient on rolling hills. At least for a mid drive.

That said, the BBS02 would go farther than my MAC10T does with Torque Assist simply because a mid drive is more efficient. But for me the MAC is a better choice.

The BBS02 typically burned 4-5 WH/mile with throttle and 6-7 WH/mile on Cadence PAS.

The MAC burns 10-11 WH/mile with throttle and 7-8 WH/mile on Torque PAS.

That's been the average of about 20-30+ rides each case on the same route same speed; 12 miles with 750 feet of climbing.

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Re: Torque assist or using throttle, which is more efficient?

Post by dogman dan » Nov 28, 2017 8:06 am

Definitely possible the guy is just stronger than you, or chooses to pedal harder, using his PAS settings to make that happen.

Cadence PAS definitely needs more tuning to your pedaling style, than just selecting 1-5. I really hate cadence PAS set to start late, and then start pulling hard. My illness means I really need the help at the first pedal stroke, not the 5th. 5th rotation would of course use less Wh on the ride.

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Re: Torque assist or using throttle, which is more efficient?

Post by craneplaneguy » Nov 28, 2017 11:26 pm

It's apples to oranges comparing our two different rides, I have a display that shows voltage and watts being consumed, he has just a percent of charge left gauge. Different size batteries, different voltages etc. I believe his Haibike has 3 assist levels? He rides in ECO, pretty sure that's the lowest, and just to tweak him a bit I mentioned that his ECO still may often be more watts that I'm using at any given moment! It's a "don't bother me with facts" kind of a discussion, that's OK we still have a good time riding together and the BIG thing is, to his disappointment I'm pretty sure, he has not been able to out ride me, at least due to me running out of power (he's a much more experienced rider then me, stronger too, this isn't about our power but our bikes). What I should do I guess is turn the tables on him, as I know I have more range, and run him into the ground, but that'd be more effort then I care to make. I'll settle for just never, NEVER...letting him out ride me, as in battery charge left.

I like the reference to a "5 speed motor", that's pretty much how I see it, what my throttle gives me is those 5 speeds/assistance, plus a few dozen more in effect, all on the fly without having to push a button to reset the PAS, and on trail riding (and that's what I'm talking about, I can see PAS being a lot more practical on street riding, and in fact use it mostly when doing so) rough and steep trail riding, no thanks I'll stick to a throttle for any needed assist.

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Re: Torque assist or using throttle, which is more efficient?

Post by Bigwheel » Dec 01, 2017 12:07 am

I don’t like PAS because of the numb feeling it gives to my preferred pedaling cadence(s) that I have adopted from years of cycling without a motor. So I use a thumb throttle and find that it does the job quite effectively and efficiently.

What really makes a throttle work for me is the “cruise control” function that I have set up through my CA V3. While cruising the flats I can set it to my desired speed and pedaling input and let the watts fall where they may. If I am going for distance watts are low and my speed is also, but always faster than I would be able to go normally. Distance not as much of an issue then both go up. Beauty is I can go up or down a gear or two to vary my cadence or adapt to undulating terrain without touching the throttle.

Climbing long steep hills is the same but I find best efficiency by backing off and only using 350w or so. Still going twice as fast as I normally would and staying out of my red zone. Same shifting and ability to keep a high cadence which I find more efficient over grinding a big gear.

I have the parameter set to activate the feature immediately which I find works the best. When a change of speed is needed a quick blip disables it or I can hit my regen button.

While not in the efficient category the ability to go full power or increase it instantly is why I will probably just stay with a throttle though. If I am going faster than I normally would be able to then that is the efficiency quotient I am looking for.

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Re: Torque assist or using throttle, which is more efficient?

Post by eCue » Dec 01, 2017 3:40 am

there can only be one , you two must dual it out ! so have a e-range race and ride too empty to see who goes the furthest per kwh riding at the same speed
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Re: Torque assist or using throttle, which is more efficient?

Post by MadRhino » Dec 01, 2017 4:06 am

Reminds me of the students who compete for the minimal energy consumed in a dull race of weird vehicles.

When I hit the trails with a fellow rider, we don’t compete for efficiency. It is the usual ‘who has the bigger one’ type of race. :twisted:
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