350htrr

Why not go for a ride and not use the re-gen braking see if you notice a difference in distance change per-charge...

powell

yES, it would be interesting to check my EPLUS distance but it is already equipped with Cycle Analist which is very nice tool on ebike,
CA calculates all kind of parameters including regen% , regenAhours among other things.

rscamp

I'm guessing you are referring to me as someone who things regen is useless. Well I never said it was useless. It can be good for braking, for example. Just that for some situations and for many people it is, practically useless.

Since you have moved the goalposts to include automobiles, then no, it is definitely not useless. But the situation changes with cars. The main reasons why are they have much greater inertia, higher speeds and a much lower drag/mass ratio. These contribute to a much higher energy recovery overall and a higher recovery ratio.

350htrr

Fine, practically useless then... And I agree, going up a hill re-gen is useless, flat ground re-gen practically useless, but most times, one is not going up a hill, and flat roads are not as flat as they sometimes seem and sometimes you are going down hills... Thus if used when practical as I use it, it easily gains me 15% distance on my normal riding per battery charge. If one thinks 15% extra distance per charge is good gain, then it's worth the doing, if one thinks 15% is not worth the effort doing then you are right, practically useless in that persons view...

rscamp

I'm glad you are happy with it. I believe you are convinced it provides you 15% range benefit.

Perhaps you could describe in detail the specifics of how you typically ride to educate me on how this level of benefit is practical on a bicycle. I can think of ways to get >15% benefit, but they aren't practical or typical.

350htrr

The trick is doing it conscientiously, (probably not typical) and willing to put in a little extra effort even when not normally needed but keeping it practical.

Up hills; Never use re-gen as that would be stupid. (unless maybe one is training)
Flat roads; When I notice that pedaling is easier I put it on level 1 re-gen, if it's still easy then I try level 2, which is usually too much so I just use level 1, (wind at my back or 0.5% downgrade even tho it looks flat)
Down hills; I put the re-gen on and depending on steepness use whatever max level that is feasible, that I can keep up speed with just a little pedaling.(instead of not pedaling)


EDIT; Page 18, BionX manual about re-gen... https://ridebionx.com/downloads/bionx...-2014-revb.pdf

It's as simple as that, Even BionX says 15% is doable, and they certainly tested it scientifically... I certainly don't raise any extra sweat doing it...

DoubleDiamonDog

I am eager to be educated but by my way of thinking, due of inefficiencies the extra effort expended on flat ground would be better spent no using regen and the rider simply applying the same amount of energy after the battery was exhausted.

rscamp

Exactly. The rider is actually expending additional energy overall applying human effort to regen. This is a net waste of energy. It is not range extension unless you cheat and ignore the human energy. On top of this, the rider must overcome additional drag at all times from motors capable of regen.

So again, I ask for the source of this regen energy that would even produce net 15% range extension - with no increase in energy required from the rider.

350htrr

You guys are totally missing the nuances when I talk about "flat" roads and re-gen and when I use it and how much I use it on "flat" roads... Probably 90% of all re-gen is done going down-hill... Also I have said that I always put in a bit more energy than "required" even going down hill...

DoubleDiamonDog

Exactly. Instead applying "a bit more energy than required" save your juice and use it when needed instead of wasting it when going downhill rather than piddling it away due to the inefficiencies of applying it to regen.

rscamp

Sorry, not trying to annoy you. Just trying to get you to see what you are missing.

When you go downhill, you use regen, correct? What happens if you go down hill without it? You go faster. This is because you have turned your potential energy of altitude into the kinetic energy of motion. If you don't need to stop what happens? You travel a long way on your kinetic energy alone. How does this compare with arriving at the bottom of the hill and having to pedal and/or use the energy stored from regen? Do you get 15% more range? Do you break even? Are you better off to stay off the brake and coast?

Yes, some of the energy is wasted mainly due to drag when you are going faster, but how does this compare with the lossy regen and power cycles?

It could be that you need to stop at the bottom of the hill. NOW using regen makes sense without a doubt! Does this happen all the time? No. It is one of those special cases. It isn't the majority of the time someone is riding. It is a once-in-a-while thing.

Are you starting to see what I am talking about? Do you see why it isn't so obvious or certain that someone will get any benefit at all from regen?

350htrr

But I don't care that I put in 1% to 5% pedaling effort going down a hill because that is what it feels like instead of 0% effort... The fact remains that the battery gets a 15% re-charge per trip and as happened more than a few times, I got to use that 15% that I wouldn't have had without the effort of using re-gen, I get 15 extra KMs where I get the E-Assist I want, instead of having to pedal 100% with no assist at all cause the battery ran out... How much extra effort would that be pedaling 15 extra KMs some of it up a hill to get home??? I always said re-gen on level roads is not worth it... Go back and re read my opinion on using re-gen on flat roads.

rscamp

You put in additional effort to enjoy some additional assist time at the end. Okay. Whatever turns your crank. You just can't call it 15% range extension or 15 extra km for the same overall energy input between you and the drive system.

350htrr

Yes, that's what I have been saying all along/trying to say anyways, there's no free lunch... You either have to pedal down hills to keep speed up on higher re-gen levels or use lower re-gen levels on most hills to keep speed up and not get much out of it like a dynamo... As for the flat road re-gen I have been agreeing that it's generally not worth it... Bottom line from my point is, that putting in a bit extra effort like I do down hills, adds up and can be worth while to extent ones battery's range to have assist when needed...

350htrr

I love these hills... Er, the down hills that is. Went for another ride today 27.6KMs total and just for fun checked my volts on my battery after 20.2KMs... 48.3v, got home after a few hills about 2 KMs uphill, about 3KMs downhill and about 2KMs normal, checked volts and found that there was more volts at 27.6KMs than at 20.2KMs.






48.6v at the end of the ride, that's 7.4KMs more and 0.3v more in the battery than before the 7.4KMs I put on...? I certainly didn't pedal anywhere close to add up to the difference, downhills are your friend when it comes to re-gen, almost free energy as I see it...



EDIT; My point is how can voltage go up in battery with use if re-gen doesn't work that good**********

350htrr

Look ma no hands... OK no legs then. Re-gen with no pedaling test. Managed to re-gen 40Wh showing on gauge without pedaling while going down hill... re-gen run https://ridewithgps.com/trips/3647272 , no re-gen run https://ridewithgps.com/trips/3667357 ,


53.1v start ride...............................0.0KM......................53.0v
52.7v start up hill............................3.2KM......................52.7v
50.5v top of hill...............................6.4KM......................50.6v
51.8v bottom of hill.......... 1.3v free .9.6KM......................50.7v
49.6v top of hill again......................12.8KM.....................49.1v
50 8v bottom of hill again.. 1.2v free.16.0KM.....................49.1v
50.3v stop ride...............................19.3KM.....................48.9v
Max 51KM/Hr..................down hill..................................69KM/Hr

100% effort free from pedaling while using re-gen gained 2.8v used from battery 19.3 KM total ride.
No re-gen numbers..................................................... 4.1v used from battery 19.4Km total ride.


31.7% re-gen happening, as I see it. And again, not realistic numbers, add flat roads and % drops fast, like 20KMs more and it's 15.8%, 20KMs more and it's 10.5%...

rscamp

Cool. You can also go to a more efficient motor to get range. The motor I use is at least 10% more efficient than an average hub motor.

DrkAngel

At "top of hill" battery will by sagging greatly (artificially low) from the prolonged drain.
At "bottom of hill" battery will have had time to recover and read a voltage bulge (artificially high) from recent charge.
Unless you stop and pause for several minutes before each reading, voltages will be skewed wildly in favor of regen.

Only reasonably accurate comparison would be to make 2 identical runs.
1. Charge, then wait several minutes for charged voltage to settle.
Record beginning voltage, run course with regen - no pedal assist of course.
Wait several minutes after finish, record finish voltage.
2 Recharge, then wait several minutes for charged voltage to settle.
Record beginning voltage, run course without regen - no pedal assist of course.
Wait several minutes after finish, record finish voltage.

350htrr

I did wait for voltage to settle/stableize, the max difference to the voltage numbers would be about 0.1v for the numbers shown even if I would have waited longer. You can see in the pic that voltage was actually 51.4v while charging, and was 50.8v at the bottom of hill after a few minutes to stabilize, same with the first downhill run, the voltage was 52.6v charging but went down to 51.8v... Same with the top of the hill numbers, I waited till the voltage number settled, and came up...


EDIT; I did go back and re-check the voltage at the end of the ride and after a few Hrs found that the voltage went up to 50.4v from 50.3v...

350htrr

Exactly, There's a lot you can do to extend range...

1; Efficient motor.
2; Bigger/better battery.
3; lighter motor & battery.
4; Using re-gen efficiently/conscientiously.
5; Pedal just a bit more.
6; Slow down just a bit.
7; Lighter bike.
8; Lower rolling resistance tires.
9; Pedal to start from a stop, then E-Assist.
10; Solar panel.
11;
Not in any particular order...

350htrr

Did no re-gen at all test, numbers added to post 66... Just in case someone interested.

SpecialX

Why do you guys keep using voltage as a marker for range?
Voltage is the worst possible indication of State of Charge for a battery..
The best way to do it, is to fully charge your battery, ride until you run out of battery (without using regen at all) and then do the same test (same route) with as much regen as possible and then you'll see the best case scenario for range extension using regen for your particular set of circumstances.
I'm pretty sure, you won't see as much range extension as you think...
Unless you have something that shows you how many WH you have gotten from regen. Then you can see what you're avg WH per Mile or KM is and work out the range extension you actually get.

I'm guessing it will be at most, between 5-10 percent..
(unless you're going downhill the entire time.. Which would skew the numbers greatly.)

I live in mostly flat South Florida, so regen is usually not of particular use for gaining range, but it does help on wear and tear on my brakes.

I have a battery that gives me on average about a 60 mile (100km) range.
So range extension via regen is not particularly useful to me anyways.

rscamp

i generally agree with you, SpecialX. Voltage can be a very poor measure of SoC, but it can also be fairly good. It depends on the batteries and the conditions under which the voltage is measured. As a very general rule, cells constructed for higher C rates have a rather flat discharge curve making it very difficult to tell the SoC - particularly when the battery is sitting between, say, 25% and 75% SoC. Some cells though have a rather more sloped voltage vs. SoC curve making it easier to pick out the SoC.

I don't know which applies in 350htrr's case, but I decided to stop posting in this thread as it became obvious no amount of information was going to change anyone's mind.

SpecialX

I see that 350 is using voltage to state regen...
Completely useless for any practical purposes...
And even IF that was not the case, any pedaling at all will not produce true numbers.

350....
If you want "true" regen numbers, you can NOT pedal at all...
Plain and simple..
(Also, you can't use only numbers from mostly a downhill run, UNLESS you recharge at the end and ALSO use the numbers from a mostly uphill run back to where you started.. But then you have to add both. )
Like I said...
Ride your battery until it goes dead and see how far you get (no pedaling).
Recharge.
Ride the same route again and see how far you get. (Remember, NO pedaling allowed)
THEN you can do simple division and see your true regen numbers.

Regen numbers can be hugely skewed, if you pedal at all..
Examples of "cheating"... Pedaling up a hill, pedaling with regen (even on downhill), pedaling on startup, pedaling with the motor running, pedaling without the motor running, etc..
See the common thread... Pedaling...

I can (Technically) say my battery has a 300 mile range, IF I'm pedaling all the time and almost never use the battery..
But my TRUE range is 60 Miles, since I've gone that far (on average), with no pedaling at all.
(I can only have 50 mile range if I got WOT the entire time or I can go 70 Miles, if I only do 18mph... But on average, I pedal a tiny bit on startups and do 20mph and get a consistent 60 Miles).
On another note, I can say I get 100% regen, if I'm pedaling all the time and almost never use the battery/motor and then use regen on the downslopes. Not an adequate measure of true regen numbers..

Another side note... I think I read somewhere that most people can put in 180w of pedaling power, which equates to 40wh in approximately 15 min of pedaling.

rscamp

...and 180W for 15 minutes is a LOT of effort for most riders.

Yup. With any unmeasured human involvement in a riding cycle the regen numbers are meaningless.

I have nothing against regen as an add on to an existing hub motor setup. It helps a bit - emphasis on a bit. But any benefit from regen is applied within the bounds of an already heavy and relatively inefficient low speed direct drive hub motor. There are other ways to provide electric assist with better overall efficiency and lower weight. Let's get more of them to market and get them on our bikes.