litchralee @ litchralee @sh.itjust.works

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120

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2 yr. ago

I don't think there's a good way to adapt this circuit to provide current limiting on the 18v rail. Supposing that it was possible, what behavior do you want to happen when reaching the current limit? Should the motor reduce its output torque when at the limit? Should the 18v rail completely shut down? Should the microcontroller be notified of the current limit so that software can deal with it? Would a simple fuse be sufficient?

All of these are possible options, but with various tradeoffs. But depending on your application, I would think the easiest design is to build sufficient capacity on the 18v rail so that the motor and 5v converter inherently never draw more current than can be provided.

Only a hub motor before, and that was just to replace the feeder wires. This was a step up in complexity.

If you do place an order, I'd also recommend getting the replacement gaskets for both sides of the motor housing. The existing gasket might stick or may not come off in one piece, and gaskets are so cheap that you might as well have a spare. Really, anything consumable that's less than $10, ought to be thrown into the order.

The catch? Hmm, I'd say it's the confusing ordering process, such as knowing which shipping option to select. Fortunately, Anna from that shop emailed me when I chose the wrong shipping option for the USA and made the correction. It took 8 calendar days to arrive, with very minimal tracking updates in the interim.

Time will tell if I chose correctly with using white lithium grease, but my research showed that: 1) the grease need to be sufficiently heavy to not fling off of the gears when spinning fast, but also 2) needs to be heat resistant, because the motor and housing can get fairly warm at full output, which would break down low-temperture grease. So I hope I chose correctly, and I'll find out in about 1500 km.

As the other commenters said, it'll be a difficult project to retrofit a replacement motor into a 15 year old frame. Not unless you or a friend can machine an adapter to fit.

From your post history, it looks like you're based in Europe. My brief understanding of Europe ebikes are that 250 W is the max continuous power, so if that's what this bike is still producing, I'm not sure if a replacement motor or even whole ebike would change that.

As for the battery, that might be worth replacing if possible, since the battery chemistry has definitely advanced. I'm a proponent of right-to-repair and making things last longer in general, so that's the route I'd take.

This is... a weird thing to design for. It's like an XY Problem on two wheels, where BMW motorbike engineers -- skilled as they are -- were fixated on "relieving" riders of the need to wear a helmet, but without asking the root question of "why do riders usually need to wear a helmet?".

The answer, of course, is that PPE is useful for mitigating the consequences of hitting the ground, a stationary object, or another vehicle. Because the laws of physics are deeply unkind to fleshy human bodies in a collision. Even crumple zones in automobiles don't mitigate the physics of a crash, hence supplementation with seat belts.

IMO, a roll cage in this application is wholly inappropriate, because it will likely just result in occupant ejection rather than any cognizable amount of protection. We need only look to trucks. No, not lifted F-150s but forklift trucks, which also have roll cages. Despite moving fairly slowly, terrain or poor driving can sometimes topple a forklift, resulting in it falling on its side. And despite the roll cage, people do still get injured. Indeed, I'm unreliably informed that in the event that a forklift is tipping over, the advice is to grab the wheel and hold on, precisely to avoid ejection and getting trapped under the roll cage itself.

2011 is quite a while ago, and a lot of ebike technology has changed since then. Is there a particular aspect of this ebike which no longer meets your needs?

I intend to do a full run from 100% battery to near zero, once the weather is a bit fairer. I would hope that there's a noticeable improvement.

Fair enough. Though I'm somewhat reluctant to reinvent the wheel -- pun intended -- when gear reduction and fast-spinning electric motors have been honed for nearly a century.

I suppose the other metric is how much power a direct drive motor can produce, but that's primarily a consideration if high acceleration or heavy hauling is needed.

I had an... oddball use-case where gears -- whether internal or through a derailleur -- were necessary for speed. That said, I once tried my hand at servicing a geared hub motor, and while that was to replace the motor wires that got snagged, I did apply some more grease when putting it back together. And I didn't think it was terribly onerous.

The main complexity was doing motor work while having to take care of the whole wheel, with spokes and tires still mounted. I much prefer the modular simplicity of a mid-drive motor, since it doesn't complicate tire changes at all. But it's certainly a tradeoff, yes.

Direct product link: https://ride1up.com/product/trailrush/

The price is good, mid-drive is good, I'm a tad confused about 250 W though, and 36 V is odd considering that other bikes in their lineup use 48 V.

Specifically, I think mid-drive really shines in mountain biking because it's substantially less fussy when changing a tire. No hub motor means no wires sticking offboard and liable to get pinched when striking a rock.

I think you'll have to provide some examples -- ideally as photos -- of streetwear fashion. Without any prior research, I only know the term to mean "comfy clothes" that would fall below the typical bar for "casual" dress code.

A quick web search shows examples ranging from perfectly reasonable outfits consisting of normally-proportioned shorts, jackets, pants, and shoes. To some outlandish outfits that are prominently displaying designer brands.

And perhaps that's the crux of the matter: what shows up on the fashion runway or "haute couture" magazines is never descriptive but prescriptive: a designer brand has a vested interest in getting the masses to believe that something is fashion so that they can move product.

Taken to the logical extreme, there is an idea that designer clothes are intentionally outlandish, precisely so that said clothes would never be worn by "normies" in day-to-day activities, and thus can always (and persistently) be projected as high-end.

Commercialized fashion is not a democratic experiment to see what most people want to wear. It is to move product every "fashion season". "Designer streetwear" is a poor approximation for what normal people wear when they just want to grab a sandwich from the bodega and then return to watch another episode from Season 2 of The Rehearsal. Maybe this should be called "real streetwear" to distinguish it from so-called designer goods.

Whoops, you're right. I misread the first sentence as though OP's brother was hired by the company. In OP's brother's case, yes, this act would appear to void any clause that would restrict writing a review, whether good or bad.

Especially for the statistician interns that are having to hide in closets to count and observe people having sex. They really didn't think they "Institute for Family Studies" would be so literal in their work.

/jk

Sadly, this act only covers "form contracts" for the sale of services or products, and doesn't look like it would extend to contracts of employment. That is, a consumer cannot be bound by a clause that prohibits writing reviews. And if a consumer of the company's products is also an employee, then this act doesn't prohibit a "no reviews" clause in the employment contract.

EDIT: I goofed at reading comprehension of OP's post. What I wrote is a correct but irrelevant analysis. This act appears to void the clause of the contract.

I often cannot find the best way to distill my own writing into a TL;DR, so I'm glad you've done it for me. I don't think I could have done it better. Thanks!

Sadly, the dataset released only counted motor vehicles collisions, with a section for motor vehicle collisions that also involved a bicycle.

This release of data sheds no light about the number of bicycle collisions that don't involve a motor vehicle. For example, a bicycle crash with a mail box, with a pedestrian, or with wildlife, we don't have those particular numbers.

[speculation begins now]

And that's a shame, because unlike motor vehicles collisions which are reported on standardized forms issued by each state's highway patrol -- because auto insurance companies and FHWA want well-organized data -- there's little inspiration to collect data for all other forms of collisions. Some states and local police departments might not even take such reports, meaning chronic underreporting of collisions due to badly-designed bike trails, due to sidewalk conflicts because no bike lanes, or with parked cars in private parking lots.

A lack of good data means no good conclusions can be drawn. We must demand better data to have any hope of finding and fixing actual problems. All the same, there's one conclusion we've known yet fail to acknowledge: cars kill bicyclists. And the exact scenario doesn't even matter, since if the car wasn't there, those bicyclists likely wouldn't have died. See my other comment.

Dobbs stressed that road safety requires cooperation from both drivers and cyclists.

They always say this, but let's have a look at the data and see if this is the right conclusion.

That linked PDF shows the number of motor vehicle collisions, broken down by scenario and counterparty type (eg none, another car, a bus, train, a pedestrian, a bicyclist). Of this data, the "bicycle involved" section is most germane, and I've copied the relevant section here.

These four lines warrant explanation as to what they're measuring. The first line counts the number of motor vehicle collisions where a bicycle was somehow part of the collision. The second line is the total number of people riding on bicycles and were in a collision counted by the first line.

The third line counts the number of motor vehicle collisions that involved a bicycle and which also killed at least one person (not necessary a motorist or bicyclist or passenger). The fourth line is the total number of bicycle riders killed in collisions that the third line counted.

Lines one and two will different because some bicycle collisions may involve a tandem bicycle (eg adult and child riding together).

But let's focus on that fourth line: out of 29 fatal motor-vehicle collisions involving bikes, it was always the bicyclist (all 29 of them) that dies. It's never the motorist that dies and the bicyclists lives. We know this because if it did happen, line four would be smaller than line three.

So when it's always the bicyclist that dies in a fatal collision, it beggars the question: does this asymmetry mean that it's fair to request equal "cooperation" from both motorists and bicyclists?

Heck no!

the dullness of it

[Press X to doubt] 😁

A phone with battle scars!

The other comments correctly explain why an index fund is probably better suited, and will preserve more value by having lower fees. But I will propound on why "universal life insurance" (whether indexed or not) might not be a good fit for you.

To explain, I have to start with what the point of life insurance even is. At its core, life insurance is supposed to provide some benefit to replace your life. That is, if when you die, you would no longer be generating income to support your family or to honor your debts (only those which continue after you're dead). Without the benefit of life insurance, the consequences might include destitution for anyone that depends on you, as well as possibly a forced sale of the family home if the mortgage goes into default. In a nutshell, if correctly set up, life insurance should approximate the value of your life, the same way that car insurance should make you whole if something happens to the car.

(I recognize that this sounds extremely morbid, to put a price on your life. But with the current socio-economic system, this is a necessary exercise)

A reasonable approximation for how much life insurance to buy is to consider how much monthly income would it take so that your family could continue as-is financially in the event that you disappeared from their lives. If the amount will cover everything from inflation, to future college funds, plus retirement savings that you would have made, then that's probably the upper-limit for the correct amount of benefit to purchase.

If you have no debts, and have no family to support, there's little point in buying life insurance. Indeed, it's not terribly profitable for insurance companies to offer just life insurance, which is why they market other types which are partially life insurance, and partially an investment. Every form of life insurance -- except fixed term life policies -- have this mix.

So the question is, do you need life insurance right now? If no, then a dedicated investment vehicle -- like an index fund -- would make more sense. And if yes, then fixed term life insurance makes more sense because it's cheap and doesn't muddle your investment portfolio. If your answer is "no, but I might need life insurance later", then with very few exceptions, you would just wait until you do need that insurance and then buy a fixed term life policy. You save money by not buying a policy earlier than you need it, but pay for it by a higher premium later in life, precisely because you're closer to death's door than you were earlier. So it's mostly a wash.

I'm of the opinion that mixing one's insurance objectives with one's investment objectives is a recipe for disaster, with the extremely narrow situation where the quirks of USA tax law means that wealthy, savvy people that plan ahead could save some tax dollars. Maybe.