The pedaling aspect is also not really what matters, because you can in principle reduce the load factor so much that the pedals also just become a fancy throttle, no?
The penalties for having such a hack detected on your bike - assuming you would get away with it - is confiscation. I would strongly advise against such tricks.
You can see how much work just changing out the battery was. There are plenty of parties selling limiter removers or speed boxes but they're all illegal and you are uninsured when using such a device. My bike is perfectly legal to ride.
This does not match reality at all. E-bikes are some of the most modify-able and hackable devices out there. Most of the parts are interchangeable, and a decent portion of these bikes are assembled piece by piece. I can change the acceleration profile of mine at will, via bluetooth. Amperage limits, battery codes, everything. I have used many devices and parts and kits, and have never even once seen DRM present.
Hint: you won't be able to, the key is embedded in an NXP processor that has it's fuses blown (both sides, controller and battery) and any kind of hacking you want to do will have to be at the sensor level and even there I would advise you to use an older version of the firmware because the newer ones are very good at detecting such hacks.
Every s-pedelec that I'm aware of is legal to buy and drive on the roads here is locked down. The Bosch system is the one that I now have extensive experience with and the handshake between the controller, the motor and then battery is of a complexity level that I have not managed to crack it despite a serious effort in that direction. Time will tell if I will eventually manage to run my own firmware but right now I'm not hopeful that that will ever happen (I'd love to update the range computation algorithm).
Regular e-bikes (the 25 kph version) are hacked with abandon but even then you are no longer legal (here, in NL and many other european countries). The Bosch system (which has substantial market share in that domain) can be hacked but only at the sensor level, and it's clever enough that it tries to detect such trickery and if it does it will brick itself. The factory diagnostic software contains a field for 'cheat detected' and it's pretty sensitive (to the point that sometimes bikes that have not been modified get flagged).
If you get a supermarket Bafang or other bike, especially older models then you are likely going to be able to hack it, but there too you won't find any s-pedelecs.
The few brands that sell them are all pretty good at locking down their stuff. Build a bike from parts and it's a different story, but then you won't get a license plate, type approval or insurance and your bike won't be legal to drive on the roads.
"These bikes" as in pedelecs in general. Not just ones with Bosch parts, and not just the ones that are available legally as regular "pedelecs" rather than "s-pedelecs" in NL or the EU. In most cases you wouldn't even need to hack them; this is how they work from the store.
I've never seen a thumb throttle burn down someones house. Alibaba batteries though? https://endless-sphere.com/forums/viewtopic.php?t=87975
Note how the theme of safety has been paramount during this build, during the use and even in case of a crash or other accident, this wasn't a 'oh let's build a pack' project done in 48 hours, you're looking at a couple of months of research and work.
As for Alibaba batteries: you get what you pay for, and I would never use a pack for a project like this with cells that I haven't tested myself, each and every one to a very high standard.
It just seems like bureacracy gone totally out of control. You take bicycles, possibly the pinnacle of appropriate technology, a set of tools can fit in a shoebox and nearly anyone can take apart and fix every last piece, and its super useful. Now incredibly there comes along additional components capable of augmenting and improving the bicycle. Add a multimeter and wirestrippers to your bike toolkit, attach a battery to your frame, replace a wheel or bottom bracket with a motor and any bike becomes an ebike, incredible. But then the law decides to ruin incredible by saying only select pre-approved models can be ridden. And making certain modifications is completely illegal, but dramatically internally modifying is allowed and even insurable.
I hope your pack is safe. Some aspects of the design seem inherently safe like using that many batteries in parallel for a 350 watt load, the peak usage will always be below the continuous rating of the cells. I'm no electrical safety professional but I have taken some workplace safety 101 online website multiple choice certification things and theres some issues i wonder about. Hopefully you've addressed and mitigated all of these concerns already, or plan to as you finalize the build, or get lucky, or are at least aware and prepared if a failure does occur. Here comes more internet stranger critique:I saw nothing about shock and vibration design, no drop tests, no mention of short circuit tests, no thermal measurements taken during a controlled charge/discharge, no mention of arc flash considerations during your assembly, first time use of a new tool that was uncontrollabe/inconsistent during assembly, possibly wasn't connected to a suitable electrical source, an ad-hoc decision to do 3x the number of welds w/no mention of ensuring that didn't overheat the cell.. And that's simple stuff any hobbyist is capable of, nothing compared to controlled third party testing that would be done to certify a commercial pack.
And how many man hours of development and testing do you think go into that commercial battery pack you can buy? Probably more than 2 months. And they're equipped with mutual nda's and proprietary data from manufacturers, vs youtube, online distributors, and some guts of a bosch bms. This was a first time pack build, manufacturers probably destructively tested more packs of each of their models than you have built, and at some point economies of scale and upfront investment give them access to superior manufacturing processes and materials. And because laws get applied equally to every person, consider this project built by another version of you, equally confident and less skilled or lucky, do they too get the official thumbs up to ride it in public?
In the USA if you wanted a 2 kwh pack you can buy them premade, although thats the largest they sell currently, and replace any ebikes battery with it, convert any bike into an ebike, or buy a third party assembled bike with it, or buy from a custom manufacturer that integrates the battery and motor into the frame itself. And needless to say you can put any motor or drive on it. But the idea of licensing, registering, and insuring a bicycle is an unheard of, and its especially word to have anyone inspect your bike or care what parts are on it. Entirely different worlds but it just feels like the European regulations introduce big limitations on the potential.
So, this is why this project took a couple of months instead of a few days. I don't just slap stuff together.
The pack is 9 layers, has two inner layers of foam to cushion shocks, is shrink wrapped twice, uses high density ABS spacers instead of glue the way other people build their packs (at the expense of some space), has the wiring very carefully routed so that shorts are not just unlikely but pretty much impossible. The 'inconsistent' welds problem was solved by the overkill method: where a manufacturer would use two welds I used six, trial welds on bad cells proved that I could not tear the cells from the welds without major damage to the cell structure, in other words: those welds are pretty solid. I also measured their internal resistance across all cell groups, and monitored each group during a pretty stressful charge/discharge cycle to see what would happen to the interconnects. On the electrical front there is thermal monitoring, voltage and current monitoring, short circuit protection, overcharge and undercharge protection.
That pack is safe, short of getting crushed.
Also, and in case you're not a aware of it, I built a one-off windmill, 5 meters in diameter, rated for 2.5 KW, had a couple of Canadian winter storms attempt to take it down but it survived everything, built an overhead crane, a computer controlled plasma cutter and owned a fair sized machine shop. I'm not your average DIY person, and spent probably more time on safety on this particular design than I did on anything else.
I would trust this pack over a manufactured one, including the ones that Bosch puts out. I didn't do a drop test but that's mostly because this is a one-off and a after a drop test I would simply discard the pack, there is no way to do that non-destructively with a battery this heavy. That said, I'm very sure that the pack inside the foam core would be fine (it's dimensioned for that) but the housing would crack for sure.
As for why the bike is still legal: type approval is mostly related to the drive train, the maximum power the motor can put out, the degree to which it amplifies the pedal input power and various cut-outs, the batteries are not subject to the type approval, you can buy and fit aftermarket batteries for many bikes.
That said, your concern is appreciated.
In what jurisdiction?
Edit: just realized it’s your article and you’re in NL. Confiscation might be an issue there but it’s not universal by any stretch.
Plenty of people 'technically' break the law in small ways every day. If your bike looks like a normal bike, and you're not doing outlandish speeds, I'm not sure it matters whether or not your bike is 'technically legal'.
My 'legalistic outlook' is mostly informed by the local news.
But don't take my word for it, have a read:
https://www.google.com/search?channel=fs&q=opgevoerde+e-bike...
Alternatively if you software configure a motor controller so that it sends motor current from a throttle instead of a torque sensor in the pedals, you'll be busted?
There is no significant difference between "pedal assist" and a hand-operated throttle. It would be really nice if the politicians would recognize this and remove the meaningless class 1 / class 2 distinction based purely on the location of the throttle. (Though to be fair there are many more sensible places which already treat them the same.)