I think the point is that if a hobbyist paying retail prices for the parts can put one together for $5k
You can build an EVSE for well under $100. The problem is you need certified parts, materials, construction methods and quality controls to maintain certification; certs are not a one-time cost and it balloons the costs all the way up the supply chain.
Yeah, 640k will be enough for everyone... (never say never).
I'm pretty confident that a typical home will never have a 480V/3Ph electrical service at 400+ amps. Not only is that amount of power completely unnecessary and cost-prohibitive, but that type of power isn't even available in most suburban residential areas. Plus it's a safety hazard in its own right. =Smidge=
The only thing that might make more money is if having an EV charger would somehow decrease vacancy..
You're assuming that a house for rent - and remember these are explicitly houses, not just rooms - is always occupied with a renter. There is no reason to think that is the case. You generally don't rent a house for a single night so the concept of "vacancy" is a little different here.
You're also assuming that someone who has had an EVSE installed would not increase the asking price, since their offering is now more valuable to a certain demographic.
In short, there is absolutely no reason to think increasing the value and appeal of their offering will NOT increase their profits; that's what every business strives to do. =Smidge=
Extra revenue from renting to people with an EV: $0
What about extra revenue from renting to people with an EV whom rented your house instead of someone else's because you had an EVSE and the other options didn't?
While you certainly COULD build an EVSE for cheap, you will not be able to build one that is certified compliant with all codes and regulatory requirements. These devices are first and foremost safety devices designed to mitigate risk of electrocution and fire, and for that purpose a $30 piece of shit will not do. No credible manufacturer would risk that liability even if it were legal.
As for L3 chargers, there are exactly zero such units available for domestic installation - and there never will be - so that point is DOA. =Smidge=
I'd say they could probably recover the costs in a few months. Basically one month's worth of rental would cover it any anything beyond that is gravy. There is essentially no recurring cost but it's a capital asset and a selling point.
Fuck, they can probably write the whole thing off as a business expense, too. =Smidge=
On the other hand, a gun has a much higher intimidation value and can be used without getting too close. This is what makes them effective tools for armed robbery - you can't stab the guy behind the counter as easily as you can shoot them, so you use a gun to intimidate and force compliance.
On the one had, I agree that a bunch of idiots wandering around with stun guns is preferable to a bunch of idiots wandering around with real guns. Not only are they less lethal than firearms, but they have a limited range so that limits the collateral damage they can do if misused.
On the other hand, the notion that using the weapon won't kill the victim may make the owner more likely to use the weapon, resulting in more injuries.
California requires warnings about metal concentrations on virutally ALL FOOD
Good. I don't see why that makes the warning useless; the effects are cumulative and people need constant reminders that they are being exposed. It keeps manufacturers and third party groups on the ball for monitoring levels to catch cases where exposure is unreasonably high. =Smidge=
Except, unlike table salt which is water soluble and excess is quickly eliminated from your body, heavy metals tend to accumulate. Small, repeated doses over a long period of time can accumulate toxic levels in your body tissues.
You're right that exposure is unavoidable, but they set exposure limits for a reason. =Smidge=
Right, once you're designing a custom motor instead of using one made for electric cars, then you can avoid or refute all arguments that are based on practical situations using retail equipment.
Why the hell would any auto manufacturer NOT use a custom motor? To try and use an off-the-shelf part would be a serious compromise in your design.
If magnetic coupling is exotic, how the heck are you going to build the custom motor?
Why would you use a magnetic bearing on a motor? Energy storage flywheels need active magnetic bearings in order to maintain their stored energy as long as possible. Motors do not need anything that fancy.
Lots of gearheads have flywheels in their garages somewhere. Not all have fancy things like vacuum packing or magnetic bearings. You actually don't need that for many use cases.
What the fuck? You DO realize there's a distinction here between a flywheel as a general concept and a flywheel specifically designed to store energy specifically as an alternative to electrochemical cells, right? When you're trying to cram kilowatt-hours or energy into a flywheel you're dealing with some serious engineering hurdles.
You really do not seem to have this concept straight in your head. We're talking about flywheel storage specifically as it pertains to automotive use as a prime mover and/or bulk energy storage. In that respect, not a single vehicle manufacturer has developed one past the prototype stage because it's a shitty way to go about it. =Smidge=
Your metabolism doesn't extract 100% of available calories, that depends on the bacteria in your gut along with a slew of other chemical activities.
It doesn't have to. At any given moment your body requires a certain amount of energy to maintain its current level of functionality. If there is more than that available, it will store the surplus. A prolonged surplus will result in the creation of fat to store it for the long term.
So if you routinely eat more calories than your body needs, you'll get fat. It doesn't matter how much of what you eat gets absorbed or what your specific caloric needs are or any other factors that change what your body needs at any given instant - eat too much, too often, you get fat. =Smidge=
You can not gain body mass unless you eat (absorb) more calories than you burn (metabolize).
Yes, there are factors that modify how much energy you burn, which are related to physiology and genetics. And yes, there are factors which determine how much of the food you shove down your throat gets absorbed.
But that doesn't change the fact that in order to gain body mass, you must consume more calories than you need at your present body mass. Want to lose weight? Eat less, exercise more. It really is that simple. =Smidge=
OK, answer me this: How much does a Calorie (kilocalorie) weigh?
How is the energy stored? Table sugar (sucrose) contains 3.87 kcal per gram. Lard is about 9 kcal per gram. How the energy is stored will change the density.
As someone else mentioned, rule of thumb is ~3500 kcal per lbs which is ~9 kcal per gram. =Smidge=
How the hell else do you get fat? You consume more calories than you burn, your body mass will increase. It's really basic thermodynamics at work here...
You may only care about "total power," but you have to actually deliver the power at the motor voltage.
And you design the motor for whatever voltage you want.
Boosting the voltage that much is going to have large switching losses and require a lot of factory-grade power supply parts.
Are you at all familiar with how modern electric vehicles work? Because that's essentially how they work... that take DC from the battery and convert it into AC. That requires "a lot of power supply parts."
How many lithium cells can you fit into a box the size of a 12V battery, limiting yourself to the same total weight? 200V or so, with way more total power,
You missed the point of the mental exercise. It doesn't matter what kind of battery you use - you can configure it to favor voltage or current. What matters is the total energy stored because that's going to drive the weight and volume of the pack.
How many lithium cells can I fit in the volume of a 12V car battery? A hell of a lot more than 200V! For the same weight I can replace a 20KG lead acid battery with 5,000 4-gram CR2032 lithium cells and get either 18,000 volts at 15mA or 3.6 volts at 75 amps. (And yes, that will just about be the same physical size too, based on rough calculations)
Switch you prismatic lithium cells and I'm sure you can do even better!
A flywheel can provide direct mechanical force using any of a variety of standard coupling methods.
Wrong. At least wrong for any energy storage flywheel worth a damn. These things are spun at 60K+ RPM in vacuum flasks on magnetic bearings - that's the only way you'll get the energy density needed to not get laughed out of the design department. You're not going to extract energy from that using "standard coupling methods." You're going to use magnetic coupling.
You do know that on-board flywheel storage has actually been tried, right? Manufacturers abandon the idea at the prototype stage because it always ends up being more trouble than it's worth compared to batteries. =Smidge=
Voltage is only half the equation; the other half is current. What you really care about is POWER.
You can absolutely build an electric car on a 12-volt battery system using exactly the same number of cells as an electric car using a 400-volt battery system. The tradeoff is the 12-volt system will need to deliver just over 33 times as many amps. That's actually not a huge problem for modern batteries, but it makes your conductors and other components huge. So ultimately a balance is struck between voltage and current.
In the end a 12-volt, 400 Amp-Hour battery will have exactly the same energy storage as a 400-volt, 12 Amp-Hour battery. =Smidge=
The low point was in 2009-2010. Things were only just getting started in 2008, so I chose that year as right before things went to shit. Early 2008 was actually a high point.
Also, "in living memory" ? Have you graduated high school yet? =Smidge=
Unemployment is down ~2% across the board since 2008.
Average hourly wage is up ~4% (Although the MEDIAN seasonally adjusted wage is down slightly, perhaps indicating a widening gap in wages?)
Perhaps the reason tech related jobs are doing relatively poorly is because they are too easily outsourced. If it doesn't matter where you are physically when you do your job, then you are literally competing with the entire planet for that job. =Smidge=
Even if space is unlimited and free, transmission will still take time. Data compression isn't going to go away unless someone solves the bandwidth problem too.
DC is harder to turn off safely. A high current contactor will arc under both AC and DC - but an AC arc tends to be self extinguishing. Solid state switching is less efficient and requires power to activate. They also tend to go up in flames when they fail.
HVDC is used only for long distance transmission, where the capacitive load for AC systems becomes a major source of loss. The only other time it makes sense is when the current required is so high, the skin effect at AC frequencies results in cables that need to be substantially larger. In cases like that, though, it's often easier to go with multiple smaller cables anyway.
AC is demonstrably easier to engineer around, and safer as a whole. There are some good arguments to be made that DC might be safer under some circumstances should you become part of the circuit - but the whole idea is that people should not become part of the circuit in the first place, so that's a non-issue.
Also, regulating DC to various voltages just means it converts it to AC first then back to DC... unless you're using linear regulators in which case the unneeded power is dumped as heat! =Smidge=
You seem to be suggesting that containers are unpacked at the dockyards. That's absolutely absurd for legal and liability reasons. The only people who are going to open up a container at the port are going to be the customs agents.
Intermodal containers are placed directly onto road trailers and train cars for transport. Repacking of goods into branded freight happens once the goods arrive at that distributor's warehouse facilities. From there the items will be unpacked and repacked as necessary to get the items where they're going.
If a shipping container has items for more than one destination, then they will only be unpacked at the logistics company's facilities. If you don't fill a container you're paying for a full container anyway because nobody but you or an authorized handler (consolidator) will mix your cargo with someone else's. That means a shipping container as a whole always has exactly one destination. =Smidge=
How well maintained is the rail network in the USA? Can it actually handle this kind of traffic?
It already does. What do you think happens to the vast majority of cargo containers that arrive in maritime ports? A short journey by truck to the rail yard and off into the heartland.
It's not high speed rail, of course - mostly for safety. But by the time you're into the intra-continental rail network you've already gotten your benefit out of the project. =Smidge=
Having a top speed of 25 knots is not the same as actually traveling at 25 knots. The trend over the past few years, especially, has been to slow down to reduce fuel consumption and save money.
And all that assumes ideal sailing conditions. =Smidge=
I had the same question, honestly. But it might have some benefits...
A cargo ship has a top speed of under 25MPH (20 knots). A Class 5 freight train can hit 80 MPH and there's no *technical* reason why they couldn't go even faster. Even with the increase in distance by taking the long way around, you can maybe reduce transit time. Such trains could also load and unload deep inland, closer to where the cargo is needed, eliminating multiple handling steps.
I still don't think it's a *good* idea, but it's slightly less crazy than it might initially sound. =Smidge=
Offer void where constant-speed is not the most efficient. Pumps and fans that can match the actual demand by varying speed will be more efficient than running a full out and bypassing or artificially increasing head pressure to get the desired flow.
You're also not going to put an across-the-line starter on a motor larger than about 50HP unless you like replacing equipment. You'll always have a soft starter to get things going - this is doubly important if you're starting the motor under load. =Smidge=
Slashdot Mirror
I think the point is that if a hobbyist paying retail prices for the parts can put one together for $5k
You can build an EVSE for well under $100. The problem is you need certified parts, materials, construction methods and quality controls to maintain certification; certs are not a one-time cost and it balloons the costs all the way up the supply chain.
Yeah, 640k will be enough for everyone... (never say never).
I'm pretty confident that a typical home will never have a 480V/3Ph electrical service at 400+ amps. Not only is that amount of power completely unnecessary and cost-prohibitive, but that type of power isn't even available in most suburban residential areas. Plus it's a safety hazard in its own right.
=Smidge=
The only thing that might make more money is if having an EV charger would somehow decrease vacancy..
You're assuming that a house for rent - and remember these are explicitly houses, not just rooms - is always occupied with a renter. There is no reason to think that is the case. You generally don't rent a house for a single night so the concept of "vacancy" is a little different here.
You're also assuming that someone who has had an EVSE installed would not increase the asking price, since their offering is now more valuable to a certain demographic.
In short, there is absolutely no reason to think increasing the value and appeal of their offering will NOT increase their profits; that's what every business strives to do.
=Smidge=
Extra revenue from renting to people with an EV: $0
What about extra revenue from renting to people with an EV whom rented your house instead of someone else's because you had an EVSE and the other options didn't?
That's +$2-3K per month easily.
=Smidge=
While you certainly COULD build an EVSE for cheap, you will not be able to build one that is certified compliant with all codes and regulatory requirements. These devices are first and foremost safety devices designed to mitigate risk of electrocution and fire, and for that purpose a $30 piece of shit will not do. No credible manufacturer would risk that liability even if it were legal.
As for L3 chargers, there are exactly zero such units available for domestic installation - and there never will be - so that point is DOA.
=Smidge=
Considering the deal is available only to AirBnB locations where they rent out the entire house, and considering the installation cost is under $1000... ...and considering renting out a house can pull in north of $20K per year...
I'd say they could probably recover the costs in a few months. Basically one month's worth of rental would cover it any anything beyond that is gravy. There is essentially no recurring cost but it's a capital asset and a selling point.
Fuck, they can probably write the whole thing off as a business expense, too.
=Smidge=
On the other hand, a gun has a much higher intimidation value and can be used without getting too close. This is what makes them effective tools for armed robbery - you can't stab the guy behind the counter as easily as you can shoot them, so you use a gun to intimidate and force compliance.
=Smidge=
On the one had, I agree that a bunch of idiots wandering around with stun guns is preferable to a bunch of idiots wandering around with real guns. Not only are they less lethal than firearms, but they have a limited range so that limits the collateral damage they can do if misused.
On the other hand, the notion that using the weapon won't kill the victim may make the owner more likely to use the weapon, resulting in more injuries.
Hmm...
=Smidge=
California requires warnings about metal concentrations on virutally ALL FOOD
Good. I don't see why that makes the warning useless; the effects are cumulative and people need constant reminders that they are being exposed. It keeps manufacturers and third party groups on the ball for monitoring levels to catch cases where exposure is unreasonably high.
=Smidge=
Except, unlike table salt which is water soluble and excess is quickly eliminated from your body, heavy metals tend to accumulate. Small, repeated doses over a long period of time can accumulate toxic levels in your body tissues.
You're right that exposure is unavoidable, but they set exposure limits for a reason.
=Smidge=
Right, once you're designing a custom motor instead of using one made for electric cars, then you can avoid or refute all arguments that are based on practical situations using retail equipment.
Why the hell would any auto manufacturer NOT use a custom motor? To try and use an off-the-shelf part would be a serious compromise in your design.
If magnetic coupling is exotic, how the heck are you going to build the custom motor?
Why would you use a magnetic bearing on a motor? Energy storage flywheels need active magnetic bearings in order to maintain their stored energy as long as possible. Motors do not need anything that fancy.
Lots of gearheads have flywheels in their garages somewhere. Not all have fancy things like vacuum packing or magnetic bearings. You actually don't need that for many use cases.
What the fuck? You DO realize there's a distinction here between a flywheel as a general concept and a flywheel specifically designed to store energy specifically as an alternative to electrochemical cells, right? When you're trying to cram kilowatt-hours or energy into a flywheel you're dealing with some serious engineering hurdles.
You really do not seem to have this concept straight in your head. We're talking about flywheel storage specifically as it pertains to automotive use as a prime mover and/or bulk energy storage. In that respect, not a single vehicle manufacturer has developed one past the prototype stage because it's a shitty way to go about it.
=Smidge=
Your metabolism doesn't extract 100% of available calories, that depends on the bacteria in your gut along with a slew of other chemical activities.
It doesn't have to. At any given moment your body requires a certain amount of energy to maintain its current level of functionality. If there is more than that available, it will store the surplus. A prolonged surplus will result in the creation of fat to store it for the long term.
So if you routinely eat more calories than your body needs, you'll get fat. It doesn't matter how much of what you eat gets absorbed or what your specific caloric needs are or any other factors that change what your body needs at any given instant - eat too much, too often, you get fat.
=Smidge=
You can not gain body mass unless you eat (absorb) more calories than you burn (metabolize).
Yes, there are factors that modify how much energy you burn, which are related to physiology and genetics. And yes, there are factors which determine how much of the food you shove down your throat gets absorbed.
But that doesn't change the fact that in order to gain body mass, you must consume more calories than you need at your present body mass. Want to lose weight? Eat less, exercise more. It really is that simple.
=Smidge=
OK, answer me this: How much does a Calorie (kilocalorie) weigh?
How is the energy stored? Table sugar (sucrose) contains 3.87 kcal per gram. Lard is about 9 kcal per gram. How the energy is stored will change the density.
As someone else mentioned, rule of thumb is ~3500 kcal per lbs which is ~9 kcal per gram.
=Smidge=
How the hell else do you get fat? You consume more calories than you burn, your body mass will increase. It's really basic thermodynamics at work here...
=Smidge=
You may only care about "total power," but you have to actually deliver the power at the motor voltage.
And you design the motor for whatever voltage you want.
Boosting the voltage that much is going to have large switching losses and require a lot of factory-grade power supply parts.
Are you at all familiar with how modern electric vehicles work? Because that's essentially how they work... that take DC from the battery and convert it into AC. That requires "a lot of power supply parts."
How many lithium cells can you fit into a box the size of a 12V battery, limiting yourself to the same total weight? 200V or so, with way more total power,
You missed the point of the mental exercise. It doesn't matter what kind of battery you use - you can configure it to favor voltage or current. What matters is the total energy stored because that's going to drive the weight and volume of the pack.
How many lithium cells can I fit in the volume of a 12V car battery? A hell of a lot more than 200V! For the same weight I can replace a 20KG lead acid battery with 5,000 4-gram CR2032 lithium cells and get either 18,000 volts at 15mA or 3.6 volts at 75 amps. (And yes, that will just about be the same physical size too, based on rough calculations)
Switch you prismatic lithium cells and I'm sure you can do even better!
A flywheel can provide direct mechanical force using any of a variety of standard coupling methods.
Wrong. At least wrong for any energy storage flywheel worth a damn. These things are spun at 60K+ RPM in vacuum flasks on magnetic bearings - that's the only way you'll get the energy density needed to not get laughed out of the design department. You're not going to extract energy from that using "standard coupling methods." You're going to use magnetic coupling.
You do know that on-board flywheel storage has actually been tried, right? Manufacturers abandon the idea at the prototype stage because it always ends up being more trouble than it's worth compared to batteries.
=Smidge=
Voltage is only half the equation; the other half is current. What you really care about is POWER.
You can absolutely build an electric car on a 12-volt battery system using exactly the same number of cells as an electric car using a 400-volt battery system. The tradeoff is the 12-volt system will need to deliver just over 33 times as many amps. That's actually not a huge problem for modern batteries, but it makes your conductors and other components huge. So ultimately a balance is struck between voltage and current.
In the end a 12-volt, 400 Amp-Hour battery will have exactly the same energy storage as a 400-volt, 12 Amp-Hour battery.
=Smidge=
The low point was in 2009-2010. Things were only just getting started in 2008, so I chose that year as right before things went to shit. Early 2008 was actually a high point.
Also, "in living memory" ? Have you graduated high school yet?
=Smidge=
Well, how do you want to measure economic health?
GDP is up ~8.5% since 2008.
DJIA is up ~18.5% since 2008.
Unemployment is down ~2% across the board since 2008.
Average hourly wage is up ~4% (Although the MEDIAN seasonally adjusted wage is down slightly, perhaps indicating a widening gap in wages?)
Perhaps the reason tech related jobs are doing relatively poorly is because they are too easily outsourced. If it doesn't matter where you are physically when you do your job, then you are literally competing with the entire planet for that job.
=Smidge=
Even if space is unlimited and free, transmission will still take time. Data compression isn't going to go away unless someone solves the bandwidth problem too.
=Smidge=
DC is harder to turn off safely. A high current contactor will arc under both AC and DC - but an AC arc tends to be self extinguishing. Solid state switching is less efficient and requires power to activate. They also tend to go up in flames when they fail.
HVDC is used only for long distance transmission, where the capacitive load for AC systems becomes a major source of loss. The only other time it makes sense is when the current required is so high, the skin effect at AC frequencies results in cables that need to be substantially larger. In cases like that, though, it's often easier to go with multiple smaller cables anyway.
AC is demonstrably easier to engineer around, and safer as a whole. There are some good arguments to be made that DC might be safer under some circumstances should you become part of the circuit - but the whole idea is that people should not become part of the circuit in the first place, so that's a non-issue.
Also, regulating DC to various voltages just means it converts it to AC first then back to DC... unless you're using linear regulators in which case the unneeded power is dumped as heat!
=Smidge=
Citation needed.
You seem to be suggesting that containers are unpacked at the dockyards. That's absolutely absurd for legal and liability reasons. The only people who are going to open up a container at the port are going to be the customs agents.
Intermodal containers are placed directly onto road trailers and train cars for transport. Repacking of goods into branded freight happens once the goods arrive at that distributor's warehouse facilities. From there the items will be unpacked and repacked as necessary to get the items where they're going.
If a shipping container has items for more than one destination, then they will only be unpacked at the logistics company's facilities. If you don't fill a container you're paying for a full container anyway because nobody but you or an authorized handler (consolidator) will mix your cargo with someone else's. That means a shipping container as a whole always has exactly one destination.
=Smidge=
How well maintained is the rail network in the USA? Can it actually handle this kind of traffic?
It already does. What do you think happens to the vast majority of cargo containers that arrive in maritime ports? A short journey by truck to the rail yard and off into the heartland.
It's not high speed rail, of course - mostly for safety. But by the time you're into the intra-continental rail network you've already gotten your benefit out of the project.
=Smidge=
My car can do 100MPH but rarely does.
Having a top speed of 25 knots is not the same as actually traveling at 25 knots. The trend over the past few years, especially, has been to slow down to reduce fuel consumption and save money.
And all that assumes ideal sailing conditions.
=Smidge=
I had the same question, honestly. But it might have some benefits...
A cargo ship has a top speed of under 25MPH (20 knots). A Class 5 freight train can hit 80 MPH and there's no *technical* reason why they couldn't go even faster. Even with the increase in distance by taking the long way around, you can maybe reduce transit time. Such trains could also load and unload deep inland, closer to where the cargo is needed, eliminating multiple handling steps.
I still don't think it's a *good* idea, but it's slightly less crazy than it might initially sound.
=Smidge=
Offer void where constant-speed is not the most efficient. Pumps and fans that can match the actual demand by varying speed will be more efficient than running a full out and bypassing or artificially increasing head pressure to get the desired flow.
You're also not going to put an across-the-line starter on a motor larger than about 50HP unless you like replacing equipment. You'll always have a soft starter to get things going - this is doubly important if you're starting the motor under load.
=Smidge=