31–40 of 213 posts
You don’t really need two ground wires, CP has a diode with series resistance 2.74K to PE (ground) so it’s trivially possible for the EVSE to just send a push/pull waveform over CP and if it reads push but not pull (remember diode) then it knows it’s connected properly. The return path for the pilot current will be over the PE contact, so it can also be detect and doubly verify that PE is low resistance, although ide…
Earlier quoted context omitted.
The system proposed in this piece could probably be safely implemented, but it would much more challenging to do than the author seems to indicate. There are a variety of failure modes that they ignore. The author also glosses over a 20% power loss (to heating), which would cost money and bulk to dissipate.
I particularly dislike how this article tries to sweep the power loss issue under the rug: The first mention of loss says that the isolation link is "responsible for about 50 percent of the charger’s power loss". The second mention of loss says "the power loss would be less than 20 percent". They want you to think that those numbers are comparable, and that they've reduced loss from 50% to 20%.
Require a coin-operated 120V outlet with gfci and accessible way to reset the breaker for every two parking spots, everywhere. Many benefits: 1. Everywhere you go, you know there'll be somewhere to charge overnight. 2. It's the cheapest per installed spot, by far, allowing way more locations. 3. Renters can safely by an electric car and have home charging. 4. Coin-op 120V are far more robust than cables with valuable…
What's a 'coin'?
The argument sounds kind of persuasive to a layman (even one that did a little bit of EE a while back), but my gut says there would be no need to write this article if there weren't regulations or other engineering traditions that decided galvanic isolation is necessary for safety. I guess the difference is galvanic isolation is physically (i.e. passively) fail safe, while ground detection is an active safety measure…
We also require arc-fault breakers in the electrical code for new construction despite even their first-order effects being negative. We're drowning in over-regulation and the most prominent people pretending to care aren't going after the real problems.
Earlier quoted context omitted.
We passed legislation spending a few billion on charging stations and totally failed to get any built.
We passed legislation authorizing spending a few billion ($7.5B, 2021 Infrastructure and Jobs Act), and have deployed a portion of it. Most of the authorized $$$ has not yet been spent; it unlocks over the decade from 2021-2030. One fault of the bill is it depends on states actually doing the work to build these stations; the feds aren't doing it directly. If states drag their feet, stations don't get built.
https://www.federalregister.gov/documents/2023/02/28/2023-03...
Folks act so salty about this all, such snark. But in my view so much was smartly done. There's so many layers of problems that needed to be tackled for consumers to actually get success, and it felt like these were gone through slowly carefully over time to make something useful and helpful.
For example, the charging standards require a certain amount of availability. Otherwise, folks might build some crappy chargers, not maintain them, and still claim money.
Folks have had all kinds of issues with chargers being not in service. Or fully used! One of the big requirements that took a while to hammer out was that chargers neede to live report their status: how many chargers are there, at what power outputs, at this location, and which are in use & what capacity is remaining? So you can get to the charger you are aiming for and have some real hope of charging up!
It's been just under two years since the standards got made. They're good, important standards, that insure this money was going to be for public benefit, that it really would tackle the problem. It is unsurprising as hell to me that there's not a ton of deployments yet!
For a "hacker news" site, I would expect a more reasonable set of expectations about product development lifecycle. Simply manufacturing compatible chargers is gonna take at least a year, in all probability. Site planning can somewhat happen in parallel, but going through the state to get the fed money is going to be a bit complex, especially at first. This stuff just takes time! The pool of money was mostly unspent, and I expect over time, as roll outs ramped up, the difficulty & costs would have been going down.
The political appetite & cycle is so contrary to the actual pace of the world some time. Sometimes we have to be willing to let good things take time to happen. It all felt so with-cause to me.
Earlier quoted context omitted.
We passed legislation authorizing spending a few billion ($7.5B, 2021 Infrastructure and Jobs Act), and have deployed a portion of it. Most of the authorized $$$ has not yet been spent; it unlocks over the decade from 2021-2030. One fault of the bill is it depends on states actually doing the work to build these stations; the feds aren't doing it directly. If states drag their feet, stations don't get built.
The timeline is even longer (and with such good cause). It also took till March 2023 to specify federal requirements for a charger! That's not a bad thing, it's not unreasonable at all. We didn't have any open systems for charging until then! There were no federal standards for what to build or how to stay or fall out of compliance! Before you start paying people to build chargers, you have to have some direction for…
It would be nice if instead of the fast charging problem the focus would be shifted to standardized battery packs, that can be field replaced. I don't really want to own 50-100kwh battery. I just want to use the charge in it and happy to pay for that.
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Heck, no need to subsidize oil or ag, they are doing fine.
How would they do w/o the current subsidies?
But a society cannot afford those cycles to play out for their food supply. Prices need to be stable and we need a slight oversupply of staples to be robust rather than perfectly efficient.
I’m not saying the subsidies are perfectly dialed in and that there’s no waste or pork. But some are very very necessary.
tl;dr existing galvanic isolation in fast chargers is very costly (~60% of capital cost) and delaying deployment of unsubsidized EV charging infrastructure; the authors think it can be replaced safely and cost-effectively with a second ground wire and some logic to detect/verify grounding.
As far as I can tell there is no source provided for the number. Nor is there are source for the stall cost.
Tesla almost certainly has the lowest stall cost on the market, while consistently providing higher uptime and reliability. I want to see numbers based on them. It is no secret that the other charging stall manufacturers are incompetent (terribly reliability and uptime), so it wouldn't surprise me if their hardware was designed poorly AND terribly high in cost.
According to a bid in Texas, Tesla's cost per stall was about 20% of competing companies. So is the cost a problem when the charger is designed correctly, or only when not?