Technology

Rad City support could not or would not explain how my battery might have stopped working, but would only say it was "not covered by warranty". They could also not explain what sort of causes of battery failure were covered by their warranty. It was pretty clear they just didn't want to cover the expense of honoring their warranty (the battery is probably one of the single most expensive parts on their bikes).

Obviously sabotage.

He weaseled his way into the company and changed an engineers documents without them noticing, causing them to over rate the motor controller......

Or just an over current, which could be as simple as surge when connecting due to a discharged capacitor.

On my RadCity 5 Plus, it was a 10 amp red mini-blade fuse. I had a "variety pack" in my car that I'd gotten at a local auto part store, but looked it up any way, just in case. This may be different on other models/batteries. Ironically, it did require a warranty voiding opening on the battery casing. :-)

There might be a reason. But if the reason really is a safety issue, then it would also blow the second fuse.

That is what fuses are made for.

It's a Hitway bk11. One of the most popular on Amazon (well I think the bk6 is).

The display for example is an S866, which are cheap and all over ebay/amazon. Heck, I could even interface an esp32 in there if I can find some documentation for the ubuiquitous 'communication protocol no.2'...

I mean sure, but at the low end of the market you can get a decent ebike with Shimano Altus shifters, disc brakes, etc for like ~$1000 which is basically getting a $700 regular bike + $300 for the ebike components.

Even a cheap car in my country. The car might actually cost less

I bought and sold my kawasaki ZR7 for around ~3k, half of what even some of the cheapest road legal E-Bike costs, more like a third of the price if you look at average.

Lifted and corrupted from Chinese, broadly: commodity made-in-China parts, gadgets, or other tat that's all largely interchangeable and cheap. Brandless or with a functionally meaningless non-brand label. The type of stuff you used to get from Chinatown, but these days you're more likely to get from Amazon, eBay, or Aliexpress.

("Yum cha" could be less idiomatically translated from Cantonese as "drink tea," more broadly to "go to the dim sum place," or later even more broadly than that, "straight from Chinatown.")

See also.

What I did was get a full rear wheel conversion kit, which comes with the motor speed controller, throttle control, most of them come with some kind of pedal assist sensors, and obviously the hub motor and rear wheel assembly. I already had a bicycle lying around. These are almost always bring-your-own battery affairs. Everything else in the kit just plugs together, and you get to decide where to route the wires down your bike frame. Maybe bring some zip ties. E-bike battery kits are readily available on Amazon or eBay, or you can have a go at making your own battery pack out of bare cells. I was lazy, so I got a premade battery pack. The only real DIY aspects I had to deal with was mating the battery pack connector to the power input on the motor speed controller box, which required some soldering (or you could use crimp connectors, I guess) and also figuring out where to mount the battery pack and motor controller to the frame of the bike.

I also decided to make my life difficult by wiring alongside this an entire secondary 12 volt system to run brake and tail lights, turn signals, a headlight, and a horn from a car (!) because if anyone runs me over they'll have no excuses. But you could easily omit all of that nonsense and deal with a lot fewer wires in your life.

I bought all of my conversion parts from Amazon. My buying strategy was just to look for stuff that had non-shill looking reviews.

Let's counter that with Prius. Featuring built-in virginity protector.

Sure, if they want the wraith of the EU on them.

The EU has a tendency to intervene when a market is unable to regulate itself.