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Show HN: Long Range E-Bike

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Re: Show HN: Long Range E-Bike

#521

Post by CRConrad »

rjbwork wrote: post #480
NikolaNovak wrote: post #370

Earlier quoted context omitted.

OK, so you disagree with assertions because you ride an illegal vehicle. And want...what? Your use case to be taken as standard? Or for people to understand there are lunatics on the road? We know :) (to be fair and charitable: I agree that moving with traffic is, everything else equal, safer than not moving with traffic. But everything else is NOT equal - I am not convinced you have the weight [i.e. centre of gravit…

No. I disagree with his assertion that one cannot go >~24MPH indefinitely. The legal limit here is 28MPH. I can certainly do so indefinitely.

1) That's a pretty high legal limit... And doesn't feel all that relevant, given that you report riding at such a ridiculously much higher speed.

2) "Moving with the speed of traffic for my safety" is a... "Nice" (that was sarcasm, I mean egocentric) attitude.

3) "The speed of traffic" may be higher for you now that you live in the countryside, but A) sounds like you rode / ride about as fast in the city, too?; and B) the typical use case relevant to the discussion is not yours but the city/suburban one.

It's bad enough that you can go so fast indefinitely; please don't.

Re: Show HN: Long Range E-Bike

#522

Post by CRConrad »

nybble41 wrote: post #308
bjourne wrote: post #302

Earlier quoted context omitted.

22 mph = 35 kmh. The average speed of Tour de France is 40 kmh: https://www.procyclingstats.com/race/tour-de-france/2016/gc/...

I wasn't talking about a long-distance race like the Tour de France. This is average speeds over a one-hour period. If an ordinary cyclist can reach those speeds, even for just a few minutes at a time, then cars need to be equipped to deal with it. The fact that an e-bike can sustain such speeds over a longer interval doesn't fundamentally change anything.

> If an ordinary cyclist can reach those speeds, even for just a few minutes at a time, then cars need to be equipped to deal with it.

Cars per se have the technical equipment to deal with that; it's the drivers' brains -- experience / expectations, basically -- that need to catch up.

Re: Show HN: Long Range E-Bike

#523

Post by sokoloff »

newaccount74 wrote: post #503
antisthenes wrote: post #498

Earlier quoted context omitted.

Nitpick to nitpick: cubically is a subset of exponentially.

You are both wrong. Air resistance increases quadratically with speed, not cubically. And you mixed up polynomial with exponential. Quadratic: x^2 Cubic: x^3 Polynomial (eg. 3rd degree): a + b x + c x^2 + d x^3 Exponential: e^x

Drag force rises quadratically with speed. Power is force dot velocity; in this case force and velocity are in the same direction, so dot product becomes simple mulitiplication making drag power (exertion, formally: work per unit time) cubic with speed.

Re: Show HN: Long Range E-Bike

#524

Post by CRConrad »

jacquesm wrote: post #423
wiether wrote: post #422

Earlier quoted context omitted.

> You're not really a regular bicycle anymore due to your speed I don't understand, ebikes are regulated and the assistance will top at 25kmh in most EU countries, which is a very average speed for a bike without assistance. Unless you're talking about speed bikes, that can ride faster but are regulated like a motorcycle with license plate and can't ride on cycle paths. So it's just an electric motorcycle that looks…

Electric moped that works like a bicycle.

Still, the "mo" in "moped" comes from "motor". It's a vehicle with a non-human power source, just like a car.

So I find it kind of weird that they're often allowed in bike lanes, especially where those are separated from pedestrians by just a painted line on a sidewalk (or sometimes even worse, explicitly mixed in with them!).

Re: Show HN: Long Range E-Bike

#525

Post by CRConrad »

moralestapia wrote: post #176
temp_praneshp wrote: post #158

Earlier quoted context omitted.

And then there are people like you and me who do neither and spend time talking shit on HN.

Well, kind of, ..., my 2021 has been one of my most productive years ever.

OK, people like him and me, then.

Re: Show HN: Long Range E-Bike

#526

Post by labawi »

awakeasleep wrote: post #460
jacquesm wrote: post #91

Earlier quoted context omitted.

Yes, that's at 5% state-of-charge, which is a bit low. If you charge up to 100% and discharge to that cut-off point you will get 300 to 400 cycles out of your battery. If you go from 80% state-of-charge down to 20% then you can get thousands of cycles out of your batteries. That's one of the reasons I designed that pack as large as it is: to stay within the 80-to-20 range on a 100 km trip.

The “charge to 80%” advice isnt generally useful to PEV riders in 2021 It is true that a lithium _cell_ lasts longer when charged to 80%, but a _battery of cells_ must be “balanced” and PEV BMSes only do that balancing in the constant voltage stage of charging in the hours after the charger indicates the battery has been fully recharged. For anyone just learning about this, an unbalanced cell is usually the cause of…

By charging and balancing individual cells, you mean group of cells that are connected in parallel (the 4P in 12S4P)? I don't see how or why would you balance individual parallel connected cells, unless you had a different battery configuration.

Simplest "balancers" drain cells that have too high a voltage as you are approaching full charge. You do need to occasionally top the battery off, to keep it balanced. Seeing they already have sense wires and discharge resistors, they could fully monitor state and balance even without top off, but that's additional code complexity.

There are nice BMSs that can shuffle charge between cell groups - they increase range by helping the weakest link, and should help longevity, by again, decreasing strain on the already worst cells. I don't know how common they are, just that they are not typical. There you can also have good and sub-optimal algorithms.

I have heard of individual cell monitoring and maybe balancing, but I have no idea what, how or why it does it.

Re: Show HN: Long Range E-Bike

#527

Post by CRConrad »

femto wrote: post #446
jacquesm wrote: post #427

Earlier quoted context omitted.

Yes, this is definitely a good point. There is an arms race like effect at work here, if you could de-escalate that lighter vehicles would be much better.

One wonders whether there is a place for "Active Crumple Zones"? Instead of a car having to weigh more that the opposition, it carries an explosive charge in it's nose, which is used to provide a burst of forward momentum to the leading edge of the car during a crash, preventing it from being forced back into the passenger compartment. One can imagine refinements, such as inertial sensing and a feedback loop to contr…

> Instead of a car having to weigh more that the opposition, it carries an explosive charge in it's nose, which is used to provide a burst of forward momentum to the leading edge of the car during a crash, preventing it from being forced back into the passenger compartment.

> Edit: I guess I'm really describing Reactive Armour for everyday vehicles.

Or basically an external airbag.

Re: Show HN: Long Range E-Bike

#528

Post by CRConrad »

yesimahuman wrote: post #215

Interesting reading this as a US resident that modded an existing bike with some parts from Grin and other places. The battery I bought has 17Ah which supposedly has ~50 miles of range which is more than enough for my needs. I'm also able to throttle control and pedal cadence control and hit top speeds of 30+ mph. It's unfortunate that modern e-bikes are so locked down and restricted because the DIY route is a lot of…

> clearly mainstream e-bikes are arbitrarily limited

I don't know that I'd call laws ensuring that high-speed motorcycles aren't allowed on mixed bicycle/pedestrian lanes just because they happen to be powered by electricity "arbitrary"; seems utterly reasonable to me. YMOV.

Re: Show HN: Long Range E-Bike

#529

Post by newaccount74 »

sokoloff wrote: post #523
newaccount74 wrote: post #503

Earlier quoted context omitted.

You are both wrong. Air resistance increases quadratically with speed, not cubically. And you mixed up polynomial with exponential. Quadratic: x^2 Cubic: x^3 Polynomial (eg. 3rd degree): a + b x + c x^2 + d x^3 Exponential: e^x

Drag force rises quadratically with speed. Power is force dot velocity; in this case force and velocity are in the same direction, so dot product becomes simple mulitiplication making drag power (exertion, formally: work per unit time) cubic with speed.

Oh, you are right! Sorry.

Re: Show HN: Long Range E-Bike

#530

Post by mellavora »

NikolaNovak wrote: post #366
rjbwork wrote: post #145

Earlier quoted context omitted.

I have an e-bike and I disagree with your assertions. I'm a fat asthmatic and I have absolutely no problem maintaining 40kph for long stretches of time on my bike. The fastest I've done on it (on a large hill but still) is 42.7MPH (~68Kph). Average cruising speed on flat land can easily be 30-33mph(48-53kph). Not all e-bikes are capable of this, but they are certainly not some kind of rare expensive impossibility - m…

If something has that average speed capability, why is not licensed, registered, insured and held accountable as any vehicle would be? My 50cc scooter appears to have comparable speeds (maybe 10kph higher), and I wear proper armour & helmet, took the classes passed the test, am registered, licenses & insured. That's my massive pet peeve & safety concern: I WANT to love e-Bikes, and all those sorts of things; and like…

In the EU, they are. Ebikes are hard-limited to 25 km/hr. If you have one which is capable of more than that (manufactured or modded), it is regarded as a motor vehicle and you need a license.
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