350htrr

[QUOTE=Doc_Wui;19352342]There are some DD kits, where the motor was designed to be throttled. Of course, with a 19 pound motor and 1000-3000 watts, who is going to pedal. I was reading their manuals to see if they had PAS, and what you do is press a button. Then you can release the throttle and pedalling acts as a switch to maintain the speed that was in effect. When I saw that, I decided not to bother with that DD kit, but I suppose I could switch controllers for one that had a better cadence system. Most of them do not act like switches.

A 3 level PAS tends to kick in most of its power as soon as the pedals turn, up to the designated speed for that level. On a lower power motor, like my 500W 36V geared hub, it is fairly smooth. It's an easy ride to 10 mph in PAS 1, and harder pedalling requires effort and I go faster. On a stronger motor, or a higher PAS level, starts would be more abrupt.

The 10 level PAS setup on a BBS02 is very smooth, and if you have a programming cable/PC , you can further adjust power delivery of the motor at a given PAS level.

The five level PAS cadence systems that I own claim "torque simulation", but they just turn down the power delivery at lower PAS levels and cadence rates. I think they work nice.

With slow speed maneuvers on a cadence system like a turn, one learns to either touch the brake to keep the motor off, or just shut off PAS. I suppose it's the samme on a T/S?[/QUOTE]

No, it's proportional at whatever level of assist you pick. You can have it in the highest setting and be in the lowest gear pedaling 80 RPM or 10 RPM and be going 5MPH because you are only putting lets say 1Lbs or 2 LBs of pressure into the pedaling effort so with my system (BionX) I control everything with how much pressure I put onto the pedals...

wphamilton

This question has bugged me for a long time. I've read the Battery University paper on it, but for some reason I'm uneasy about their conclusions.

Anyway, Table 2 lists charging cycle life vs depth of discharge:
100% DoD 300–500 cycles
50% DoD 1,200–1,500
25% DoD 2,000–2,500
10% DoD 3,750–4,700

It's really the total amount of charging over the life of the battery that we're concerned about, right? So I normalized this by the total charge and made this simple graph, which shows that you get the best battery life if you charge it when it's half depleted. As you suggested here.

But, in Table 4 they show that if you only partially charge the batteries, to 60-65% of the full charge, you'd get something like 4 times the battery life (by total amount of electricity stored and used)! So if you bought twice the battery you needed, and only ever charged it to 65%, you'd come out way ahead in the long run. I'd never have the discipline for that though. I always want the full charge, the full range or time of use of the charged battery.

Although ... I don't think that chargers try to go higher than about 3.9 or 4 volts, so the "fully" charged voltage is already the optimal 3.92 volts of Table 4?

2old

Patrick, what I'm referring to is ascending tortuous (for me) areas; if I stop pedaling (for instance in a very tight switchback or sudden large rock to inch over) on my RPM-based system, the bike stops; with the more sophisticated units, as long as there is pressure on the pedals, the motor keeps "assisting". Fine line, but sometimes the difference between making it or walking the rest of the way. Road riding, which I rarely do, this isn't a consideration.

CrankyOne

Thanks for the info. Your descriptions make cadence sound much better than anything I've ever experienced. All BBS02 or BBSHD?

Most of the torque systems I've used, and possibly all, don't require anything special for slow speed or any other maneuver. If you let up on pedaling so does the motor. I've mostly ridden in something like 40% mode so for every watt I put in the motor puts in 0.4w. If I let up on pedaling the motor does proportionally as well. Same for 100%, 150%, or whatever. It's usually quite invisible except for pedaling being easier. The only time I've really noticed anything is on first starting there's often a slight bump about and 1/8th of a crank turn in when the motor kicks in but this is usually quite gradual.

I did find your "On a lower power motor, like my 500W 36V geared hub" interesting. I'd consider anything over 250w high power and it seems rare that I ever see anything larger in Europe. 250w is higher than most tour riders average on a stage and can maintain about 25 MPH for an average 170 lb person on a 40 lb bike.

NoPhart

Thanks, but do you know what type/makeup of lithium ion?

CrankyOne

The two ends of the battery are fairly equivalent in their impact on battery life. At least with a Tesla BMS. Using 60% charge from 60 to 0 is about equivalent to using 100 to 40%. If you need to use 60% of the battery then the best is to use 80 to 20%. If tomorrow you'll need 40% then tonight charge to 70% and use it down to 30%.

FWIW, I'm at 1132 charge cycles on my Model S over 29 months and still have 95% of my original capacity.

350htrr

Nope, No idea.

wphamilton

The two extremes (100% and 10%) appear to be about the same life for depth of discharge. In other words (to recap) just discharging and charging the top 10% we get about 10 times as many charge cycles in the battery's life as we would for discharging all the way, and about the same amount of total charge and discharge.

But that doesn't seem to be the case for how high you charge it. Have a look at Table 4 in that Battery University link. Charging only to 3.9 volts (60% of full), it shows eight times the number of lifetime discharge cycles as charging to 4.2V (full up). It doesn't say how much was discharged in the cycles, but a full discharge would yield five times the life charging to the lower level. So between 5 and 8 times better for that slice.

The explanation given is that the lower top voltage "eliminates all voltage-related stress", but "negates the benefit of Li-ion in terms of high specific energy."

As I mentioned it makes me uneasy about the conclusions, because you'd think that 5 to 8 times better life would be important enough to mention frequently in product specs, in all of the advice columns about care of batteries, and I'd expect any charger to have adjustable cut-off voltages. Maybe I'm interpreting it wrong, maybe their measurements are flawed, or maybe people only care about total capacity when buying batteries. But I'm going to measure the voltage on my charged headlight battery pack, and if it's higher than 4.0 find some way to limit the charger. I'll bet that the Tesla has that already built into the battery controller.

speedy25

My cheap Sondors has PAS. You pedal. The motor starts. Stop pedaling and the motor stops giving assist too. It works well. I would pick that over a bunch of torque sensor bikes I have ridden, but there are better ones that work well.

Ride a bunch of different bikes. I went to two e-bike expos just for that reason. To see what bikes and systems ride the best. It was well worth air fare to San Diego to do the first one I went to.

Anyone who wants to be critical of the bike they may spend a few grand on should do the same.

-SP

BobG

Lithium Manganese Cobalt according to...https://electricbikereview.com/bionx/s-350/

Rick Imby

I recently purchased and added the bbs02 to a nice old bike that fits me well.
I did not expect to use the throttle much. I have been riding in the snow---Montana---and while riding on snow packed trails I love both the throttle and the assist mode. I bought the 30 tooth gear for it also.

I bought the unit so I could have a bike for a friend to ride that does not ride much and they would be able to keep up with me---they will kill me barely working in assist 1 never mind 2,3,4,5.

I bought the battery and drive unit from Luna.

The 30 tooth sprocket is good for the snow but will not work for me when the snow is gone. (I like a 60-80 cadence) I cannot ride on flat ground with the assist on even with a studded tire on the front because I spin too fast with the 30t up front and an 11 tooth in the back ( I have a 9 speed). I am comfortable at about 12 mph with the 30/11 combo and I do not need assist at that level.

The throttle takes a little to get used to as it gives a pretty strong boost but is really handy when headed into or over a snow drift.

I also like the throttle for getting out of the way of traffic.

I will go with the accessory 42 tooth Luna Chainring which will be perfect for my friends to ride with me. I would highly recommend it for you also.

Yesterday I was running a little late for a breakfast meeting 5 miles away with snow packed roads. I hopped on the bike and put it on assist 2. With very little work, but higher rpm than I normally ride, I rode the whole way at 19-20 mph. On my regular studded tire bike I would have been at about 12 mph and get there all sweated out due to the snowpack and snow I was riding through.



This bike would work fine for my usage with just the assist or just the throttle. I will probably readjust the assist to have lower levels of assist, I cannot imagine using the 3,4,5 assist under normal riding.

I am an avid cyclist in good shape and want the assist for riding like on a bicycle, not an electric motorcycle.

I hope this helps PatrickGSR--

I have motorcycled it home on the bike path with a 44 ounce coke in one hand. A completely unusual experience.

Rick Imby

With many battery operated Items ---bikes included---500 charges is the full life of the item... With the e-bikes the limit is almost always---how far will it go on a charge?

Luna has $100 chargers you can set to charge the battery up to 80%, 90% or 100% for both 48v and 52v battery packs---

wphamilton

500 full charges is the (max) full life of the battery. But only charge it to 60-65% instead of 100%, and 4,000 charges is the life of the battery.

I think that you're confirming that we care mostly about the battery capacity and not the battery life for most items, because we only even consider the full charge. Objectively, I'm that way myself. Give up a day or half a day of run-time on my phone's charge, just to make the battery last longer? Would I rather have it last for 2 or 3 years but only ever use 65% of the battery? No way, I'll just buy another battery in a year. But I did just now download a battery app to cut of charging at around 80% or 90% - all I really care about is one day of use.

On an e-bike battery pack costing $600 or more to replace, that would be another story. I'd want to get the 4,000 charge cycles out of it instead of 500, if I could. So if this is all correct, buying twice the battery you need and charging it only to 60% is far and away the best strategy cost-wise.

Rick Imby

I agree with you--I bought the Luna Charger I can set to 80% max charge---and that is how I will charge almost all the time. I bought a 13.5 amphour 52volt battery and have ridden 40+ miles with less than 50% of battery usage.

350htrr

Talking about chargers... I was just charging my battery today even tho I haven't used it for 3+ months and it was full when I put it away but now the orange light is on instead of the green (BionX), I would suspect recharge lifespan also depends on the charger, if you don't have the exact charger for your type of battery it could also drastically reduce your battery's lifespan...

My thought's on the Tesla 80% is best recharge number for the battery... TIME, people just don't like to wait around for a full charge if it takes 4Hrs to do it "properly" meaning you actually can charge it 100% full and not loose any lifespan of the battery but it would take lets say 4 Hrs, so, 45 minutes and you get 80% and keep the lifetime of the battery in-tact, compared to charging it 100% in 1 Hr and loosing 1/2 of the life time charging capability of the battery, so, well that is more than good enough... IMO as to why this 80% number is floating around... It's time, NOT that you would loose the batteries lifespan because you charged it to 100% capacity, it's the time it would take to do it "properly" that is the problem... JMO

slomoshun

This whole video is well worth a view but start at 18:00 for some good battery info.

2old

Interesting, thanks SM; one thing he said in a post on ES was that LiFePO4 batteries don't follow the same degradation pattern as the other Lithium batteries they have tested. What is neat (to me) about my Yamaha system is it exhibits the % charge remaining in individual increments; I had been keeping it between 20% & 80%, but maybe 10% & 60-70% is better. It seems to use one % per mile at the lowest PAS setting; 180 pound rider, no wind, flat terrain.

350htrr

What I got out of that video is, it's heat that wrecks the batteries over the last 20% to full... and when you fully charge them they heat up too much... Thus my theory about time it takes still stands. A proper charger designed to fully charge that certain type of battery without degrading it, well I still say it can be done, it just take a little, make that a lot more time to not over heat the battery...

I have watched the numbers going up while charging my deep cycle batteries and they go up fast, lets say from
10% to 60% in about 1/2 Hr, then from
60% to 80% another 1 Hr, then from
80% to 90% another 1 Hr, or more and to finish from
90% to 100% it can take another 1 1/2Hrs

Never "actually timed them" but have done it for years and years, and those times seem about right.

Dunbar

That video convinced me to buy the Cycle Satiator. Once I get my (expensive) 1KwH battery for my Cross Current I don't intend to charge it over 80% except when absolutely necessary. The cool thing about the Cycle Satiator is you can load multiple customer charge profiles (50%, 60%, 70% etc) and even select the maximum amps of the charge (lower is better if you have the time.)

350htrr

And that's great, But most people have too small of a battery to begin with, because of the cost... JMO

So, charging a battery up to only 50% or so, would Probably, end up as a fail for 90% of the people... JMO

I am suggesting one should be spending moneys on a "proper" charger specifically designed for the type of battery you have ( that allows for pulsing and cool down near the end to minimize heat and charge to full), to use more of the battery without such a large loss in lifespan... At the inconvenience of longer charge times...

EDIT; Which could actually be the Cycle saturator, but one must "know" how to use it set it up properly for their specific battery type, which I would also say 90% of the people out there haven't a clue how to do... againJMO

Dunbar

It's diminishing returns if you charge the battery below 60%. But even charging to 80% gets you like 3-4X the cycle life. I will admit that for the average person the 400 cycles they get out of a battery charging to 100% is probably several years of use. If you commute on your e-bike, or just ride it a lot like me, that 400 cycles can happen in a year or less. My current battery runs $600 retail so going the bigger battery route and charging to <80% can make financial sense. The Cycle Satiator pulls back the amperage as you get near the target charge voltage. If I have the time I charge at 1 amp which means each 18650 cell only sees 1/4 of an amp. I recommend getting the 72V version of the Satiator if you buy it as the charger will work up to 84V systems which future-proofs you if you get a new e-bike.

kickstart

I just test rode a Rad Power Radwagon with cadence sensor, and at the lower 3 power settings it felt very natural with the additional boost being very subtle, the sensation being like a regular bike on the flat with a tailwind. The top 2 power settings it still feels fairly natural but the additional boost is very noticeable leaving no doubt there's a motor assisting.
I was a little put off that the Radwagon also has a throttle....until I rode it. It takes about a half to full revolution of the crank for the assist to kick in, and at the lower assist levels acceleration is slow. The throttle really shines when starting on a steep hill, or when crossing a busy intersection when one wants to get going with some authority. IMO, the thumb throttle is so inexpensive there's no harm in giving it a try to form your own conclusion.

FWIW,, the Radwagon is a 75 lb longtail cargo bike, things may be different on a lighter bike.

350htrr

NOW that, I have a bit of a problem with, no way would you gain that much... IMO

I think this is all based on Tesla charge cycles where they pump the battery up to 80% in less than 40 minutes, and that is good enough, because "if" they kept pumping it in at that rate it would damage the battery, but if the person really wants 100% they can still do it at home, it would just take 3 or 4+ Hrs on top of the 40 minutes, and the batteries would still last the whole life cycles they should last, charging them up to 100%, but, just pumping it up to 80% fast charging is as good as it gets balancing both time, and charge levels... JMO

In other words, I don't believe a battery would last 3-4X longer just charging it to 80% instead of 100% if charged at the "proper" rate,
... " if", you take the proper amount of time with a charger meant to do that.

PatrickGSR94

Nice, thanks for posting your experiences. I'll likely start out with the stock Bafang 46 tooth ring, which also happens to be the size of the largest of the triple rings currently on my utility bike, currently 3x8 with 11-28 cassette. I won't have any snow to deal with, pretty much ever, so I think the 46 ring should do pretty well.

Cool, sounds good. I'm guessing my bike with e-parts added will come in around 50 pounds or so, hopefully. Still lightweight compared to a cargo bike! But I will be pulling 60+ pounds of trailer and groceries from time to time.

chas58

Best of both worlds: A torque simulating cadence sensor. I'm thinking of getting one of those, as they are said to be almost as good as a torque sensor that costs much, much more.