Battery prices are getting really low, if you're willing to do some DIY. Just received a 15kWh battery from China. A 'Humsienk'. Combined it with a GroWatt SPA3000TL-BL inverter.
Total price, 1600 euros. So close to the magical 100 euros per kWh. Driving it with some interesting combinations of Raspberry PI's and serial interfaces and custom written Go code, but it works... :)
Did the same, got a solar installer to fit panels on garage and a solis hybrid inverter. They fitted a CT clamp on my meter and a lora device on both sides for it to communicate with the inverter.
Then bought a 16kwh battery for ~£1500, installation was plugging in a positive, negative and ethernet cable and configuring the inverter to use the battery. (if my home insnurer is reading this, I had an electrician friend double check while helping with some other work)
Definitely recommended for anyone who likes tinkering, thousands cheaper than installer pricing.
UK considerations: must be at least signed off by an approved electrician ("Part P" regulations), and for any situations involving subsidy needs to be MCS approved as well. https://mcscertified.com/
Find an electrician who will inspect and sign off on your work. It's not illegal as licensed master electricians have mechanics do all the grunt work who are unlicensed. The electrician vouches for his employees work which legitimizes it. No different than you doing the work and having the electrician inspect, call out issues to fix, and inspect again until no issues are found and sign off.
Surely it only needs to be signed off if you intend to sell the property with them or sell excess back to the grid. If youre just using the batteries how is anyone going to know?
If the DIY work wasn't the cause for the fire it shouldn't matter, but I half-expect someone to inform me that US insurance companies can (legally) deny coverage for reasons unrelated to the accident.
Not so fast. Have you very carefully read the full small print of the insurance policy? Did you review that with a lawyer? Is incredible how different "normal" people vs. lawyers can understand a contract.
I'm pretty sure there is a clause, which states that you have to inform if you have and/or are not allowed to have fire loads, or anything that could cause a fire, or make it worse, or something along the lines in legalese. These formulations are always there because of people hoarding fuel in the basement, for example, or O2 Tank, or whatever. They are formulated in the most generic way possible to catch anything you do "wrong". Failing to follow such clauses, also when not explicitly stated, is dropping your obligations in the contract. And then there will be a clause that of course says, that not following the contract from your side, also exempts the company of paying.
Note also there are clauses that are very softly specified, like "use rooms for the intended purpose" which may be a problem if you store idk, paint in the garage, which may be flammable, in which case a fire in the garage will not be (at least fully) covered.
If is something does happen, and Li Batteries catching fire is not something unheard of, you will be in a world of suffering. Probably having no home, and having to pay damages to the neighbors. All to save what? 2k$... 5k$?
Theoretically a good choice, but where I live, just doesn't work. Either they just say "no thanks" or they will be more expensive than letting them do the whole job.
I got the "trick" recommended to do the things yourself, then call a certified guy, and say "look, I contracted a guy, I had no idea, he came did everything, but I got a bad vibe, I would like you check the whole installation". But it also does not really work, they will come with a contract, where you are enforced to contract them to correct any findings. And boy they will find things then...
It "may" not be permitted, but if you live in a collection of shacks in rural Colorado that were themselves -already- completely un-permitted then you might decide that it's best to just do the work yourself.
I do wish I could have a good, in-depth tutorial on how to set this up myself. Along with (pipe dream) an explanation of how it would interact with my local utility. I worry that due to some silly technicality, I won't be able to export to my local utility, or else I won't be able to run off-grid when there's an outage.
I will do a write-up in a couple of days. It's all relatively simple, you just have to expect terrible documentation and do a bit of reverse engineering and serial sniffing. I expected the battery to be complicated, but it turned out that the inverter was.
You'll encounter stuff like: manual says use RS485 port on Battery for GroWatt inverter → need to use CAN port on Battery. Meter Port (RS485 [serial] over RJ45) wiring on GroWatt is unknown (A: white orange / B: white blue, cross them over). Dinky RS485 serial → USB converter needs a 120ohm resistor between pins for line termination. Growatt meter port expects a SDM630 meter, not a DTSU666 (hardcoded), so vibe code another emulator. DIP switches for RS232 connection need to be both on the ON position (undocumented). CH340 USB→serial converter for RS232 does not work, but one with a Prolific chip does. Etc. etc. etc :)
Oh, and the biggest one... I was expecting to be able to just send a command, 'charge at 500watts', now... 'discharge at 2000watts'. But no. You have to emulate a power meter and the inverter will try to bring the net power to 0. Fun! :)
> Driving it with some interesting combinations of Raspberry PI's and serial interfaces and custom written Go code, but it works... :)
What protocol is it speaking? I've seen some of the more mainstream models call out that they use Modbus but all the cheap import models either might use Modbus or some custom protocol you have to reverse engineer or hope someone else did.
Yup, Growatt is the Chinese OEM that Base Power white labels to pretend it does US manufacturing. In fact this stuff is low quality. You need to be careful. There are gradations of quality at cell, pack, inverter, control levels. You will be crushed if you realize you AliExpressed your way to a home power "solution" only to have it fail young.
Feel you have more unknowns on the safety front? vs. the expensive off-the-shelf. [in the USA, it’d also be “fewer names to sue” in that unlikely tragedy of combustion in home, but no euro/kWh targets there]
LFP batteries are as likely to burn down your house as a stack of wood is. I'd be worried about the inverter or botched DIY wiring (especially not to spec torque on terminal connections and botched crimps leading to hot spots), but not about the batteries themselves. For a person who wants to save some money, but doesn't know how to work with electricity, the best move is probably to get cheap LFP cells from China, but have a professional install a BMS and the remainder of the solar system.
> especially not to spec torque on terminal connections and botched crimps leading to hot spots
This was indeed my greatest concern. However the battery came with pre-crimped very solid DC wires, and nice push connectors for the battery itself. The battery also has an integrated DC breaker (great!).
The system runs 3KW max, so I just added an additional breaker (with RCD integrated) in the conduit box. In NL this is something a DIY-home owner easily can do themselves :) (just use the right solid/flex stranded cabling for the connectors, etc...)
And further, my position has been that learning the correct methods, paying a lot of attention to details, and not being cheap with tools is -still- cheaper and probably more reliable than paying contractors. I have only used my hydraulic crimper for a pair of cables, but it was the correct tool and did good work.
I'm not interfacing with a grid, and there are already code issues with my places- I'd probably feel different if I could get insurance on my place.
Cheap chinese tooling and youtube (plus pretty good general literacy) go a long way in this world.
And FWIW, I live in the US west and am way more worried about fire coming from outside than from the batteries.
> LFP batteries are as likely to burn down your house as a stack of wood is.
LFP batteries are much safer than past chemistries, but this statement is way too broad.
High power batteries are always more dangerous than something like a stack of wood, because batteries will gladly dump their entire energy capacity very rapidly into a short.
Even if the battery itself [mostly] won't self-immolate, the entire installation can be a fire hazard.
On a tangent, I’m amazed at how bad most random crimps I see on the internet are. Also, the number of people who debate the use of solder on crimps without discussing potential issues with said solder is too high.
As a EU-citizen, I'm not happy with this legislation and enforcement. I choose Apple versus Android, because I want the safe and user friendly ecosystem Apple offers. Otherwise, it makes much more sense to go with Android. Those phones are much cheaper and are very much the same quality-wise (performance, screen, form factor...).
The same goes with iOS on iPad. I'm very happy that my parents can use those devices versus a Windows machine (or even a MacBook) and know that they are pretty much safe from malware.
Even now, I noticed that with the mandatory browser selection screen both my parents independently have moved on from built-in Safari to Chrome (independently), since that was the only browser name they know. And now they are in a much worse position privacy-wise than before. Which is certainly not in the spirit of the GDPR and DMA.
You're upset that your parents were free to make some choice that you feel is wrong, and you believe Apple should be allowed to take that choice away from them?
Honestly, I feel that Apple has completely brainwashed some people. Comments like yours abound, complaining about the dangers and disadvantages of freedom and choice. You're only a few words away from "freedom is slavery".
You're assuming the OPs parents made an informed choice. Chrome might be the only name they recognized so they picked it. Is Chrome really the best choice for them? Hard to know. A bunch of choices up front is also generally bad UX. Reasonable defaults that can be changed later are likely better for the average user.
No, I'm not assuming that. The freedom to make a choice is not contingent on your being informed. Imagine being kept in jail with the pretext "you are not yet fully informed of what is out there, so we're not letting you go out for your own good".
Anyway, OP can just inform their parents and fix this thing, if that was really the problem.
> Is Chrome really the best choice for them? Hard to know.
If you imagine this is a good argument for taking choice away from people, you are damaged. There is no freedom if you get to restrict people until they will make the choice you feel is perfect for them. Freedom means freedom to make mistakes. It's not like Chrome is explosive, and if handled incorrectly it may kill its user and some innocent bystanders to boot.
I also said that it should be changeable later - so I'm not taking away anyones choice. Sticking a bunch of questions in front of a user, when all they really want to do is use their new phone almost feels like a dark pattern. They just pick whatever and move on. Is that really any better than default that can be changed later? IDK, other than randomly getting people using something different.
> Imagine being kept in jail with the pretext "you are not yet fully informed of what is out there, so we're not letting you go out for your own good".
Isn't this basically what school is for children?
I don't think it's crazy that people might have a range of preferences for how "locked down" a device or ecosystem is. One end of the spectrum might be Linux phones and the other might be those Jitterbug (?) phones for old people that can only dial a few preset numbers. Android would be more towards Linux and Apple more towards Jitterbug.
But I do think Apple should be more transparent with their users, and has generally been "maliciously complying" with these regulations.
considering all this ai gen improvements, you should talk to them not just about browsers... scams that do imit ppl's voices are on the rise, you should also talk to them about being virgilent about some websites that do try to trick ppl, maybe even give some examples. The web is not safe and soon it'll be even less safe if there are photos of you/videos with your voice registered & available online
I have to explain on average once a month to family why some websites break on "the Apple internet app" (safari) and they should use Firefox or Chrome for critical stuff instead.
Had to explain again yesterday because Safari crashed to a white screen error on my wife's macbook while she was trying to buy plane tickets.
Very much. I am the 'tech person' whithin family and friends. I used to just do everything for them which was a chore. Since then I have discovered if I educate them on what a browser is, the choices they have, and how you can try multiple ones if you are having issues, then they very often start solving problems and looking further into things themselves.
People very often dont have a clue what things like app permissions are and just blindly accept them all. Aftrer educating and showing them, they are much more careful in checking what they are accepting.
Teach a person to fish is my motto, you should try it sometime!
I dont see why that opinion deserves downvotes but there you go.
No, of course, everyone should be free to have the choice to install whichever software they want on devices that they own. E.g. put the phone in developer/hobbyist mode by connecting it with a USB cable to a PC, show some big fat warnings, and then allow all forms of sideloading. But it needs to be like a safety switch.
Then the matter of an informed browser choice. This is simply not a thing most regular people make or care about. Remember the Internet Explorer era? In this case, simply the most recognisable picture gets chosen (e.g. the only company that advertised their browser).
The general argument is that the changes end up being annoying.
Simplest example would be 1st party apps only vs including 3rd party apps. Clearly there are implications around including 3rd party apps that would affect the operating system and thus user experience
iPhones can still come with Safari installed and used by default, no changes to anyones experience at all. But if I want to go to the app store, install a different browser engine, and set it as default, how does that affect any users that are just using the default device as supplied to them?
There is no reason at all to hinder this choice. It does not affect 1st party apps, or how the device works by default. It just allows choice for those who want to explore it.
> iPhones can still come with Safari installed and used by default, no changes to anyones experience at all.
No, this is not allowed and currently also not the case. When you're setting up a new iPhone, one of the questions during setup is which browser do you want to use.
I agree, except Windows had a massive PC monopoly back then. Apple doesnt have nearly that same monopoly today. It shares it with Google and in some markets it lags behind Googles user numbers.
Suppose there were a rule that there could be no defaults ever, and all of the apps are randomly arranged in the App Store for the sake of fairness.
Your argument would be equally true, you could just scroll and scroll until you find the app you’re looking for, but surely you’d agree the experience would be worse?
Because web sites will start using Chrome only features and stick a big box over the page insisting the user switch. Unless, of course, you want to pass complete control over web standards to Google.
See GDPR side effect of annoying banners everywhere even if I don't give a damn about my website visits information being processed, for how unintended consequences played out and made the web worse for everyone.
For DMA specifically, see Apple withholding Screen Mirroring (a feature I would enjoy tremendously) from EU for fear (IMHO quite reasonable) that the vaguely written DMA could be interpreted as requiring them to open mirroring to 3rd parties.
It's been just a few months and already DMA impacted my enjoyment of my devices, no?
the only problem with gdpr is that it didn't push far enough. If your browser provides a header with accept/reject all, a banner should not be shown. Also, GDPR does have many other interesting things, including being able to download/delete your data
Just for your info, the banners are absolutely not required and they are the band aid solution of websites who don't give a crap about their users.
If you also don't care about yourself, it's worse for you but many others now have the chance to deny providers of their scummy way to make money off unwitting users.
Parent is right, banners are not required by GDPR. These websites do not reflect the people in the organisations they represent, they are made by developers like the rest of us who are following the crowd like sheep.
3. Analytics cookies
We use these purely for internal research on how we can improve the service we provide for all our users.
The cookies simply assess how you interact with our website – as an anonymous user (they data gathered does not identify you personally).
Also, this data is not shared with any third parties or used for any other purpose. The anonymised statistics could be shared with contractors working on communication projects under contractual agreement with the European Commission.
However, you are free to refuse these types of cookies – either via the cookie banner you will see on the first page you visit or at Europa Analytics.
That appears to be things covered by the GDPR and that they need some way to inform you that you can reject them ... and that's done with a banner that allows you to reject those cookies.
Given that analytics is used, and that has cookies that track information, they're required to have that notification somehow. That page doesn't appear to be a "developers following the crowd like sheep" but rather "the requirements of the law are followed to the spirit and letter and the easiest and most accessible way to provide that functionality is with a banner."
The banner works for its requirements with GDPR and meets the requirements for accessibility.
Surely, one cannot expect that companies trying to save costs will go through great lengths to implement something that they don't know if it will work or not or if they'll get sued in the EU if they implement a different solution when the EU themselves implement it this way.
If there is a better way of doing it that doesn't lead to lawsuits, the EU's website should be the first ones to implement and demonstrate an easier and more accessible way to comply with the GPDR.
As it is, the websites of europa.eu are setting the standard for companies to follow when they want to make sure that they don't get sued for failure to comply with the GPDR for website notifications and accessibility within the EU.
This is an issue I regulary face, people not being educated on what the damn thing actually is. A general catchall banner on intial website load is the laziest and most intrusive way to get compliance, but its the easiest for developers so they generally take that way out.
As a company, if I were to implement something that is unknown to be in compliance with the spirit or letter of the GDPR, it is possible that the company would get sued within the EU.
The way to ensure that you don't get sued is to copy the structure of the one website that you know is in compliance with the GPDR and follow their lead.
When reading the GPDR text from https://eur-lex.europa.eu/homepage.html I see a cookie banner. If it works there and that is the example of how to be in compliance with the obligations of a website for cookies? Would some other implementation that isn't done that way be risky in that the courts in Europe could decide that it wasn't done correctly?
Until the websites of europa.eu change to show an alternative way to be in compliance with cookie notification for the GDPR, banners remain the least risky (and yes, easiest and laziest) way to try to remain in compliance.
Nothing in the GPDR says "thou shalt have a banner" - but that's not the issue at hand. What is the least risky way for a company to implement the requirements of GDPR given that's the way europa.eu does it?
It's interesting the views in the threads of "screw your parents if they can't figure out how to protect themselves w/o iOS/AppStore" to "we must think of the children and protect them from cookies"
as eu citizen i'm happy with it. I have both a pixel and an iphone and imo you can continue using app store apps if you are afraid of security (let's not dive into this argument, bc the statements about security in some cases are false), while others will use other app stores when/where they want, that's kinda the point, you as a user can decide what to do. If you are afraid about your grandma/kids installing something, I'm fairly sure there's(or will be) an option in settings to limit such actions.
It's true that ppl do need more education related to digital privacy, on the other hand, who knows if chrome is much worse than safari, and if they use chrome on their laptops... chances are the data is already collected, if they use google - data is already collected.
> I choose Apple versus Android, because I want the safe and user friendly ecosystem Apple offers.
Me too.
> The same goes with iOS on iPad. I'm very happy that my parents can use those devices versus a Windows machine (or even a MacBook) and know that they are pretty much safe from malware.
iOS (and Android) are very different position, security-wise, than desktop operating systems (Windows, Linux, macOS) because of the strong application isolation and permissions system. On a desktop OS ~any software you run has access to ~all your files (https://xkcd.com/1200/). Even as a die-hard desktop Linux user, we have to recognize that Apple leads in platform security, both in mobile and on the desktop. Take a look at Hector Martin’s (from Asahi Linux) thoughts on this.
> both my parents independently have moved on from built-in Safari to Chrome (independently), since that was the only browser name they know. And now they are in a much worse position privacy-wise than before. Which is certainly not in the spirit of the GDPR and DMA.
Two thoughts here: 1) the point of the GDPR and DMA is to give people the choice. In my opinion, choice is good. 2) people choosing things that hinder their privacy because they “don’t know better” is, well, an education problem.
Of course the GDPR/ePrivacy directive is notorious for lax enforcement (it’s ramping up, though) of illegal techniques and dark patterns like making it more difficult to reject unnecessary spyware cookies than to accept them. I predict the same will happen with the DMA.
It's not an alternative viewpoint, it's just plain missing the point.
The strength of Apple products and their ecosystem does not require apple forcing a monopoly on payments in their ecosystem.
If they stop abusing their position, their products will be just as good and as secure. I don't see the correlation between the article linked and that comment
a lot of people actually clueless on why apple charge a fee so they are like, why are you charging? the web didn't charge me either. when in fact apple provides all the infrastructure, distribution, security, payment system.
You seem to be saying 'Look at all this infrastructure Apple gives you for free, of course you should pay them their cut'.
You could look at it the other way and say 'They made all this infrastructure in order to lock in vendors and monopolise the app market, thereby forcing you to pay them their cut'.
If posts on HN are anything to go by, it seems this perspective is decided simply by whether you like Apple or not!
Is that sarcastic? If not I feel you have missed the point of this whole thread/argument.
People would rather the freedom to choose what they buy, who they buy it from, and where they buy it. This freedom of choice is much more important to a great many people than being locked in to a service 'because its good'.
This is indeed the main problem. If you have two screens of the same model, the OS is unable to see which is which. This also goes for many USB devices (such as webcams that randomly swap).
Ok but then it could at least say "there is a screen plugged into port 1, and the same serial in port 2, so I'll draw the things that were on port 1 there again"?
That way it would be up to the user to plug the same screen into the same port, which I think I could handle.
Plus I can see the serials are actually different, so just going by serials should work.
Or it should just tell you "hey buddy, you've got two screens with the same serial and that's why I don't know what to do"
>Ok but then it could at least say "there is a screen plugged into port 1, and the same serial in port 2, so I'll draw the things that were on port 1 there again"?
Yes, this is the strange thing. It's not like it's guessing which monitor is which, it's always swapped.
Agreed. In my case with a 15" MBP M1 Max and two LG UltraFine 5K's, which I always plug in the same ports, 99% of the time it remembers which display is which correctly. On my 2018 Intel, this was hit and miss. It's obviously not a trivial problem to solve...
Nice article. Wondering though why trading is not done in discrete batches, e.g. 5 second intervals? Trades in the same interval get filled equally or stochastically? Info about trades with that same 5 second batch delay? Is there some (theoretical) market efficiency thing at play? All this HFT feels wasteful and bad for 'regular' human investors.
> All this HFT feels wasteful and bad for 'regular' human investors.
Quite the opposite, thanks to the tough competition the market makers are setting the bid/asks spreads as minimal as possible. Which leads to less costs for human investors, pension funds, insurance companies etc.
I used to be a market maker in the 90's before HFT took off. The margins we kept sometimes felt like a rip off but customers had no other choice but to accept them.
People who ask for transaction fees, forced delays in executing or whatever, tend to forget that these force market makers to increase their spreads, which means customers eventually pay the price.
>Quite the opposite, thanks to the tough competition the market makers are setting the bid/asks spreads as minimal as possible. Which leads to less costs for human investors, pension funds, insurance companies etc.
It's not automatically the case that the disappeared margins & thinning of bid/asks have been shared equitably between the trading firms and customers.
Take two exaggerated markets for example:
1) No HFTs: The customer wants 100 shares in Company A. The shares are available on two exchanges, one at $100, and another at $105. A market maker charges the customer $5 to access the 100 shares at $1 each. The customer pays $105. The market maker earns $5.
2) With HFTs: The customer wants 100 shares in Company A. The shares are available on two exchanges, one at $100, and another at $105. The customer clicks "buy" on their trading platform, the HFT races to the $100 shares, and purchases them, then fulfills the order at $105. The customer pays $105. The HFT firm earns $5.
For the end-customer, all that's happened is the margin goes to another firm. The consumer still has no other choice but to accept these transaction fees. There was arguably a need for HFTs to reduce the market-makers exorbitant fees in the 2000's, but that requirement has been served, and the technology now exists to remove both from the market entirely.
HFTs are a rent-seeking entity interjecting in a market which, at least in theory, exists to most efficiently allocate capital to the productive benefit of all.
In the United States at least both scenarios you mentioned are illegal. Market makers are not just sitting in the middle of orders. They buy without a seller lined up and then fill orders from their own inventory (or route orders to an exchange in the case where they can't fill a buy order from their own inventory). In cases where they route to an exchange they are required by law to fill the order at the lowest price available. Typically they fill orders at better prices than what you can get on an exchange. So you, as a retail investor, are actually getting better prices than you would if your broker just filled orders on an exchange.
How the price improvement gets allocated is complicated. Some of the price improvement goes to the broker (in the form a payment-for-order-flow) and some goes to the actual investor (you). But in either case the retail investors are strictly better off.
Latency Arbitrage still exists in a world with NBBO regulations. Research consistently finds that not only does the strategy work in theory, but that it is consistently put into practice by HFT firms to the detriment of other market participants. If a firm can calculate the NBBO ahead of other market participants and the market regulator, it can still legally front-run the market, and risklessly extract rents from end-customers. The NBBO formula is not computationally expensive, and its underlying data is necessarily publicly available to all trading firms. This occurs in the real world, in the order of $billions annually.
The UK's Financial Conduct Authority:
>We use stock exchange message data to quantify the negative aspect of high-frequency trading, known as “latency arbitrage.” The key difference between message data and widely-familiar limit order book data is that message data contain attempts to trade or cancel that fail. This allows the researcher to observe both winners and losers in a race, whereas in limit order book data you cannot see the losers, so you cannot directly see the races. We find that latency-arbitrage races are very frequent (one per minute for FTSE 100 stocks), extremely fast (the modal race lasts 5-10 millionths of a second), and account for a large portion of overall trading volume (about 20%). Race participation is concentrated, with the top-3 firms accounting for over half of all race wins and losses. Our main estimates suggest that eliminating latency arbitrage would reduce the cost of trading by 17% and that the total sums at stake are on the order of $5 billion annually in global equity markets
The University of Michigan's Economics department:
>We illustrate this process and the potential for latency arbitrage in Figure 1. Given order information from exchanges, the SIP takes some finite time, say δ milliseconds, to compute and disseminate the NBBO. A computationally advantaged trader who can process the order stream in less than δ milliseconds can simply out-compute the SIP to derive NBBO,a projection of the future NBBO that will be seen by the public. By anticipating future NBBO, an HFT algorithm can capitalize on cross-market disparities before they are reflected in the public price quote, in effect jumping ahead of incoming orders to pocket a small but sure profit. Naturally this precipitates an arms race, as an even faster trader can calculate an NBBO* to see the future of NBBO, and so on.
>Conservative estimates suggest that at least 4% of dark trading occurs at stale reference prices. High-frequency trading firms (HFTs) almost always benefit from such stale prices, being on the profitable side of the trades between 96 and 99% of the time. Furthermore, stale trading does not happen at random but is driven by the behaviour of HFTs. HFTs as a group almost never provide marketable liquidity in the dark and rather behave strategically to exploit their speed advantage by submitting marketable orders to execute against stale quotes.
I described the canonical front-running example in my first comment, as it gives most non-finance readers a quick overview of how HFTs work, without needing to describe regulations, strategies, NBBO, SIP, etc.
The specific strategy currently employed by HFTs is somewhat immaterial in the broader context of a discussion about front-running. For as long as a firm can legally front-run the market with any strategy, it can undermine the market and risklessly extract profits.
This is entirely false and ignores Reg NMS. Everyone must execute at the NBBO. As well customer orders are often given better and tighter prices than other market participants. HFT firms will often offer them better than NBBO prices. As well, none of these prices you quote would not exist without market makers, its just now the fact that to be a market maker you must be an HFT firm as well due to the scale that is now required.
This is how the Taiwan exchange used to do matching, and I still think it's the best system I've seen.
I don't think the reason has anything to do with price discovery, it's just because exchanges want to maximise their trading fees. Continuous order book trading leads to more trades and hence more profit for the exchange.
They also charge differently (extortionately, some might say) for different speeds of data feed, although I'm not sure if they have tiers just for HFTs.
The HFT is wasteful but isn't bad for human traders, they tend to get better prices. It's bad (sometimes) for huge investors (VHNW individuals, hedge funds, pension funds which I guess represent regular people) that want to make large trades without moving the market but there are also winners here - e.g. if Johnny the day trader buys a stock that Texas Teachers Fund is selling huge batches of, he's better off if HFTs are causing price changes to propagate more quickly.
Those batched trades are called “auctions” and they are a part of many exchanges.
I think it’s pretty uncommon to do them every N seconds.
A common pattern is to collect quotes before the market open, do an “opening auction” to set the opening price, and then switch to continuous trading for the rest of the day. If trading in a stock ever pauses (which can happen for a variety of reasons) then another auction occurs when trading is restarted.
IIRC they have done trials of this on some exchanges. It didn't make a big difference either way. The opening and closing auctions are already sort of done the way you describe.
If you think about it you can never eliminate the advantage of being faster. If you do 5 seconds batches it just means the edges of the batches become the time-sensitive points.
If you want to kill HFT you can do it directly via very very small transaction fees. But guess how popular that is...
> If you think about it you can never eliminate the advantage of being faster. If you do 5 seconds batches it just means the edges of the batches become the time-sensitive points.
You mean you can never completely eliminate the advantage? But mostly eliminating it might still be useful?
Suppose the rule is that if you get your request in by 01:23:45 then it gets handled in the following 5-second period and the response is sent out at 01:23:50. Does someone (A) who finalises their request at 01:23:44.9999 and gets the result back at 01:23:50.0001 have an advantage over someone else (B) who has to finalise their request by 01:23:44.8 and gets their result back at 01:23:50.2? Yes, certainly, but it doesn't seem to be much of an advantage ... So person A can take account of exciting news that arrives at 01:23:44.9, while person B can't, true, but when it comes to reacting to other trades, person A has 4.9998 seconds to think about the news, while person B has 4.6 seconds to think about it, which doesn't seem like a huge difference. Compared to how things work today.
It's funny that you say that, with the crypto transaction fees still a big problem. Feels like HFT and crypto are on a convergence towards that concern.
Exchanges already extract per order commissions. You do not pay per message (so add, cancels and amends are free, you only pay when you get traded [1]).
A per-message would probably significantly affect existing strategies and greatly increase spreads, but I don't think it would prevent all forms of ULL trading.
[1] But even there exchanges offer rebates, if not outright incentives, for market makers to provide liquidity.
You could match what you can distributed equally and leave the rest unsettled.
You could let people decide whether to roll-over the partial bid into a new bid on the next clock or to cancel unsettled.
You could clock to something both very fast on a human scale (50ms), quick enough it'd still feel instant but slow enough that it could reduce HFT silliness and need for extreme low latencies.
> You could match what you can distributed equally and leave the rest unsettled.
Equally per market participant? Do large participant like banks trade same amount as retail investor one trade at a time?
Per quantity? HFT will time the end of the interval and decide to place a large order or not.
It would be weighted by bid size. If there's $10m of bids one side and $5m of offers on the other, you match up the $5m on that side and every bid gets 50% settled.
I'm not sure I understand the problem with "waiting" for the end of the clock. The pool wouldn't be public so you couldn't get knowledge inspecting the pool. All bids and offers would be published on the clock and settled by weighing all the bids and offers against each other and matching by volume.
The trickier issue is what happens in this scenario (assuming limit orders):
Person A bids for 500 units @62
Person B offers 100 units @61
Person C offers 400 units @60
Clearly there needs to be full settlement, we have a bidder who wants to buy 500 units at a price which sellers are happy to sell at.
Correct me if I'm wrong, but in a traditional market it would depend on the order they came in.
Here we would need a formula to work out the correct settlement price. Intuitively this ought to be somewhere just above 61. ( If it were just two people, a bid at 62 and an offer at 60, you could intuit a fair settlement would be 61. )
The general rule is HFT will have the elite level mathematicians to figure out what is the most optimal strategy is, and the most exotic hardware to implement it to the extreme. Other party will fall further behind given the more complex and unconventional exchange rule.
You trade latency arbitrage with statistical arbitrage were participants try to estimate the market and overbid to try to capture as much of the market as possible. That seems dangerous and unstable.
This is all gameable. Like he said, you just time it with an over-large order and let the remainder expire. Everyone gets 10% of their order but my order is 10x what I actually want so I actually get 100%.
Per rata matching is already a thing in some financial markets. They tend to be _more_ latency sensitive as size gets inflated to game the matching algo, thus risk being inflated and thus the value of timely cancels.
They already do this for the opening and closing auctions. You can have a market-on-close order or limit-on-close order for example. The market on close orders are guaranteed to fill. The limit orders are filled using price-time priority, so best prices submitted earliest fill first, after the market price orders.
I guess it is possible that there are remaining marketable orders that never fill because of an imbalance one way or the other, but I doubt that ever happens in practice.
I really enjoy my second hand 2020 Model 3 LR. Amazing car, never had any issues. If I compare it to my father's 2022 Kia EV6, it's still leagues ahead.
Serious answer: it entirely depends on the variety of tomatoes being grown. There are some varieties that have been selected for taste. Typically, they will also have a very efficient supply chain with a super short duration between harvest to packaging to supermarket (packaging at the greenhouse, straight to distribution, to retail). They are typically about three times the price of the cheapest 'bulk' tomatoes (and also have a higher margin, in the end).
The main challenge with fruits, and especially tomatoes, is ripening versus shelf life. A tomato tastes best when it's as ripe as possible. Sweet, fragrant and full of flavor. However, at that very special time, it will burst on the vine or fall apart in your fruit basket within a day. Which is why you'll never find this quality in a supermarket. And why I grow tomatoes in my garden every summer :)
Great answer. I honestly love a great tomato, it can make 5th place burger #1, and I can eat it like an apple no problem, but it's tricky to get in the city.
When I renovated my house, I installed such a heat exchanging pipe. It reduces hot water usage (=fossil gas) by about 40% and with my usage payed itself back in about two years. It's not a drop-in replacement, since you should use it only for the shower drain.
No, it preheats the cold water connected to your shower. Warmer cold water means you need less hot water to achieve the same temperature in the shower.
Total price, 1600 euros. So close to the magical 100 euros per kWh. Driving it with some interesting combinations of Raspberry PI's and serial interfaces and custom written Go code, but it works... :)