I assumed the post title meant nanometers. Why? Floating-point rounding bugs. A nanometer is about 9e-15 degrees of latitude, which is right about where a double-precision floating point number runs out of digits. So, if a piece of software uses exact `==` equality, it could easily have a bug where two positions 3600 nanometers apart are seen as being different, even though they should be treated as the same.
Thank you. People can be very bad about judging which scenarios are truly implausible.
Here’s a previous thread where someone thought it was absurd that there could exist native English speakers who don’t regularly go shopping, and treated that supposed impossibility as a huge “checkmate”!
React Native added auto-linking years ago, which solved the native dependency problems. Just `yarn add` whatever you need, and if it has native code, the the Android side will incorporate it on the next build. On the iOS side, you do have to run `pod install` to lock in the changes, but everything after that is automatic.
Use Expo because you like the extra features it ships with, but not because you have problems with native dependencies. The React Native built-in experience is pretty much perfect to start with.
Each OS process has its own virtual address space, which is why one process cannot read another's memory. The CPU implements these address spaces in hardware, since literally every memory read or write needs to have its address translated from virtual to physical.
The CPU's address translation process relies on tables that the OS sets up. For instance, one table entry might say that the 4K memory chunk with virtual address 0x21000-0x21fff maps to physical address 0xf56e3000, and is both executable and read-only. So yes, the OS sets up the tables, but the hardware implements the protection.
Since memory protection is a hardware feature, the hardware needs to decide how fine-grained the pages are. It's possible to build a CPU with byte-level protection, but this would be crazy-inefficient. Bigger pages mean less translation work, but they can also create more wasted space. Sizes in the 4K-64K range seem to offer good tradeoffs for everyday workloads.
Just because some people do bad things does not mean you get to paint the whole group with those crimes. Imagine if you had said, "Black people are criminals, because a black person robbed the liquor store down the street last week." We all (hopefully) recognize the deep racism in this statement!
Unfortunately, there are parts of the country where this type of racism is acceptable and even common. There as similar attitudes towards Catholics, due to America's history as a predominately protestant country. The formula is the same both way - pick a heinous crime from a few members, blame it on the group as a whole, and feel smug about yourself.
Nah. When I am taking a road trip, the last thing I want to do register an account for some random charging network I'm never going to use again (because I'm in a different part of the world). I just want to pay for my power and move on, just like I can pay for food or anything else on the trip.
When I am at home, I plug my car in and it goes on my monthly power bill. This is where the convenience matters.
If it's an international network, you'll probably use it again and it's probably not "some random" charging network. Agree about home convenience though.
I recently build my own a level 2 EV charger from an OpenEVSE kit. The heart of the charger is a big mechanical relay, which connects and disconnects the charging cable based on whether a car is connected. To control the relay, there is a small circuit board that communicates with the car, and also provides over-current, over-temperature, and GFCI monitoring. If any of these things go wrong, the relay will not close and the car will not charge.
The DC fast chargers include similar safety features, in addition to a big AC-DC converter. The DC power supply puts out several hundred amps at whatever voltage the car requests (usually 300V, but sometimes much higher). Normally, currents this high would require super thick & heavy cables, but DC fast chargers often avoid this using water cooling and active temperature monitoring in the cable. As the cable heats up from the excessive current, the charging equipment actively throttles the charging session to keep things from melting.
So yeah, there are a few mechanical things that can go wrong.
To deal with the high current on such relatively high (keyword here: relatively) gauge wire there's also massive active cooling involve. This adds even more to the complexity.
Please explain. I keep hearing this meme, but the arguments don't make sense. For instance, people will say things like, "New World Order wants us all to use electric vehicles so they can limit our movement!" This is backwards, though, because electric cars can plug in anywhere, but gasoline stations are much more centralized and easy to regulate. If I were the Global Elite, I wouldn't want people producing power on their own rooftops, storing it in batteries, and driving around with it. Green technologies seem to lower costs and increase resilience for the average person. What am I missing?
This seems like a good idea. We have used gas taxes for a long time, but electric cars don't pay this tax. If we want to pay for roads based on how much people use them, we will need to switch to something other than gas taxes. Odometer readings could work, but it's not clear how to get honest readings. Weight isn't perfect, but it seems like a less-bad options than the others.
Many states are now adding fixed registration taxes for EVs, usually in the ballpark of $200/year. I pay this, and it costs significantly more than if I had paid gas tax on an ICE car of a similar weight for the miles I drive.
Also fun was that this remained full price during the year that my state suspended its gas tax for economic relief due to high gas prices.
Weight and mileage based taxation absolutely makes sense, since road damage increases with the 4th power of axle load. But matching those taxes to damage caused means heavy trucks will pay the vast majority of tax, since they do the vast majority of damage. This may be unpopular with Amazon.
To add to this, the Missouri yearly tax is already higher than gas taxes for most vehicles, and it's legislated to go up 20% a year every year until 2026. Taxes high enough that the economic gains for electric are basically zero.
I hadn't heard this, but I'm not surprised. The right wing has essentially declared culture war on EVs. They will tax them out of existence, if they can.
My fairly outdated small but somewhat sporty car with high consumption (9l/100km rounded up) would go 5600 kms from that. Here EVs have to pay no excise and no parking fees and no yearly engine-power based taxes for their cars, while ICEs must, based on age, environmental category and engine power...
Compared to that you still pay some taxes, still that amount is negligible to the taxes some pay for ordinary ICE cars.
Get honest readings by having them read at the annual vehicle test in states that do it, and self reported in other states. Then have police report it whenever they pull you over for any reason.
You don't need to get perfect readings from everyone. If you tax 99% of people, that's fine.
Many jurisdictions require annual inspections. Those jurisdictions could require the inspection include reporting the odometer to the state.
Adding an odometer only inspection requirement to jurisdictions that don’t currently have an inspection wouldn’t be terribly onerous. You could make a device that plugs into ODBII and reads the odometer and VIN and reports it to the state, it would take less than a minute of labor per reading. Combine that with some policies that encourage oil and lube shops to get the device and provide the reading at no extra cost when you’re doing an oil change, and most people wouldn’t see any increased costs or inconvenience.
In most countries, cars are required to get an annual inspection which includes the odometer readings. It would be quite easy to also tax based on that, but it would have to be retrospective.
Odometer reading might be tricky in places like Europe where you have lots of countries next to each other, and cross borders often.
If someone has a car registered in Luxembourg and drives mainly around France, Germany, Belgium, it would be difficult to define where the tax should go
I recently installed an Enphase home backup system as a DIY project (crazy, I know). The biggest problem with any home-backup system is moving the loads onto their own sub-panel. When the utility goes down, power needs to flow into the home, but not to the rest of the neighborhood. To do this, a switch needs to physically disconnect the utility meter from the main loads panel. If this isn't possible (such as when the meter is integrated into the panel), all the loads need to move to a sub-panel. This is the hard part.
Once the meter and main panel are separate, the various backup solutions become pretty similar. The disconnect switch installs between the two, with the solar and battery attached. Sometimes the disconnect switch + solar + battery are all in one unit (like the Bluetti EP900), while sometimes the solar inverter, battery, and switch are all separate units (like Tesla or Enphase). The Tesla switch and battery are sleek & glossy, but the inverters are ugly. The Enphase stuff isn't quite as shiny, but at least the boxes look consistent.
Performance-wise, the systems seem pretty similar as well. Most systems are around $10K for 10KWh of capacity, with somewhere around 6-9 KW of peak discharge rate. I imagine these prices will drop a lot over the next decades. If the battery becomes obsolete, just install a different system. Once the home is correctly wired, swapping the storage system should be pretty straightforward.
Is it currently possible to do this with a battery setup, for which its normal state is to feed power to the grid with anti-islanding?
Either you'd need two power connections to the panel - one for the every day anti-islanded backfeed, and then a second with the physical lockout to a different inverter output that operates without the grid.
Or the lockout on the main breaker would need to control a logic-level switch that told the inverter to disable anti-islanding, for power flowing through a separate non-locked-out breaker. This would seem like a better solution, but the inverter/battery manufacturer would have to design for it and get NRTL approval.
You don't move the loads to the sub panel. You make a new main panel, move the feed to that, and turn the old main panel into a sub panel. Much easier.
The National Electrical Code contains the rules for this sort of thing, plus whatever extra rules your local jurisdiction adds. I bought a copy of the code itself plus an "Illustrated Guide to the National Electrical Code" to learn this stuff. There are lots of YouTube videos for electricians, by electricians. DIY channels can also be helpful, but they don't always follow code.
In my case, the local utility requires the electrical meter to be accessible (obviously) and to be a certain distance from the gas meter (obviously). Because of the way my house is shaped, there simply isn't room to move the electrical meter, so a sub-panel was the simplest option. Anything else would involve tearing open the driveway, which would be worse. It really depends on the situation.
It'll give you a really good introduction to house electrical systems, things like "any panel that is connected directly to the utility is the main panel, any panel that is connected to a panel with a shutoff is a sub panel".
You don’t need an isolation switch if you use a sol ark 15k or EG4 18k, you can just tie the grid straight in and they have isolation built in if the grid goes down.
I like the distributed architecture. Each solar panel has its own inverter, as well as each battery. If I want more panels or batteries, I just add them in parallel with the existing panels or batteries. If a panel or battery goes down, the remaining ones keep working. Avoiding high-voltage DC also makes the project more DIY-friendly. The downside is that Enphase requires users to take online classes before they grant access to the installer app (easy but time-consuming).
Right now I have 3.8KW of solar and a single 3.3KWh battery. We are producing more than we use most months, so the solar is good but the battery is undersized. If we have an extended grid-down scenario like what happened in Texas, the system will mainly provide daytime backup plus a few evening hours. This is still better than nothing, and we can easily add more batteries as we have the budget.
Thanks for the info. Do you know how much you saved by doing the install yourself? Did you also do the solar install? I was considering using a battery to time shift power as my power provider has free nights.
I installed the solar first, which cost about $10k for parts, plans, and permits. I got quotes between $18k - $26k for the same-sized system professionally installed, so this was a great savings for 3-4 weekends of physical effort.
I don't know how much I saved on the battery, since I didn't get any quotes. The battery was vastly more time and effort, since I had to move my house onto that backup loads panel.
If you just want to shift usage, the backup panel may not be necessary. The Enphase batteries do support a fully grid-tied mode, where they simply connect to your main panel as a branch circuit. I'm sure other brands do too. This would be an easy DIY weekend project, as opposed to a months-long home re-wiring project. The Enphase mandatory training would be the biggest downside for using them here.
Not the person you asked, but Enphase has a reputation of being much more reliable then the Tesla stuff. You can have up to 40kWh of batteries. I think the peak wattage is also higher per kWh than powerwalls.
Also, we tried to get Tesla to install solar on our roof, and will never do business with them (especially that half of the company) again. There's a reason their solar market share is plummeting. Many news stories have been written on this subject. I won't repeat them here.
LG and Generac also make home batteries. From what I can tell, their offerings are also fine.
The main limitation of all the existing systems (vs. the recently-announced Anker) is that they scale amperage linearly with capacity. This is a pain because the batteries produce way more current than you need, but you have to pay for an electrical bus that can handle peak output. This is why the enphase is limited to 40kWh.
I'd strongly recommend against trying to do the installation of the Enphase yourself. It's extremely hands on.
I didn't see much in the way of details on the Anker site regarding their system. It seems none of the companies selling their systems make it as easy as tesla to order one.
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