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I think this "electric grid can't handle it" is another piece of anti-EV FUD that is not representative of the situation in reality. Right now, peak electricit

by jblow 14y ago

I think this "electric grid can't handle it" is another piece of anti-EV FUD that is not representative of the situation in reality. Right now, peak electricity usage times are during the day. This is why in most urban areas electricity is cheaper at night: they want to encourage you to distribute your usage more evenly throughout the day. The NEMA 14-50 (a.k.a. standard appliance outlet that most people plug their dryers into) is a totally fine plug for an EV. It will charge the car up fully overnight. This plug is going to deliver you, at maximum, 40 amps at 220 volts. Electric dryers often use something like 25 amps at 220 volts (of course it varies by machine). This is not far from the 40 amps we are talking about. So this whole "grid can't handle it" pseudo-panic is sort of like worrying that everyone is going to run their dryer at the same time, times 1.5, at off-peak hours. It is just not a big deal. FUD.

danielweber 14y ago
The grid is not a big bucket. The local conditions matter. Your local neighborhood transformer might be serving only 5 houses. If one or two of them decide to charge an EV every night, the transformer may not get a chance to ever cool down, like it is designed to do.
CamperBob2 14y ago
Oh, hey, this is JM from RAD. Didn't see your user name at first. :) Re: 220V outlets, it's surprisingly hard to find the true average power consumption by a dryer, now that I just tried. I do know that the heating element in a dryer is usually rated for 5000 watts+, but you have to keep in mind that it doesn't run at a 100% duty cycle, even on high heat. (I can't find anything that talks about what the typical duty cycle on high heat is, so maybe I'll measure mine the next time I dry something.) I'm pretty sure it would more or less nuke your clothes if the dryer dissipated over 5000 watts all the time. Point being, if an EV charger really does draw 40 amps at 220 volts, that is about twice the real power consumption of a clothes dryer. This is a non-trivial amount of juice. It would be a massive problem if half the automobile-owning households in the US started charging their cars all night long at those rates. It's not just a matter of you not personally having any use for swappable batteries. It's a matter of electricity not being quite as trivial to generate and distribute as you suggest. Nobody that I'm aware of, including me, is trying to spread FUD. I would gay-marry Elon Musk, if I were gay. I wish him all the success in the world. But the numbers behind his prediction simply do not work... unless he has something up his sleeve along the lines of the Better Place concept.
- jblow 14y ago
  Oh, hey dude. 40 amps at 200v will completely charge a Roadster in something like 7 hours. I don't know how long for a Model S, but it is probably longer. I am only familiar with the day-in, day-out of the Roadster so I will stick to that mostly. So the "charge the car all night (7-8 hours) scenario" only makes sense if you need to charge up the battery 100%, i.e. you were on fumes before you plugged it in, which means you drove 200-240 miles the day before. This may be true for some people but it is not going to be true for most people most of the time. I drive from SF to Berkeley and back most work days, a 25-minute commute each way, and I like to drive it like a sports car, so I use relatively a lot of power for that length of trip. Generally I use about 20% of the Roadster's battery on such a day, so that's probably about 1.5 hours to charge in a 220V outlet. If everyone did that, you would probably want to stagger the charging times, but it is totally doable even with current setups. I do think that there would be some increased power draw and that we would want to beef up our electricity infrastructure a little. But that is pretty different than what I see as a Republican talking point, which is something like "there is no way that the USA can support everyone plugging in their EV, it's impossible." That is not my experience as an EV driver. When I was coming up with the dryer analogy I was just using numbers I pulled off the Internet about what people were measuring their dryer's pull at. It's possible dryers just are not very efficient, I don't know! (Though I thought the whole Energy Star thing was supposed to put pressure on that).
- aidenn0 14y ago
  And this would be a problem if half the ICE car owning public went out and bought electric cars all in the same month. There will be time to upgrade the distribution grid.
  - CamperBob2 14y ago
    Before 2025? Will never happen.

by jblow 14y ago

danielweber 14y ago

The grid is not a big bucket. The local conditions matter. Your local neighborhood transformer might be serving only 5 houses. If one or two of them decide to charge an EV every night, the transformer may not get a chance to ever cool down, like it is designed to do.

CamperBob2 14y ago

Oh, hey, this is JM from RAD. Didn't see your user name at first. :) Re: 220V outlets, it's surprisingly hard to find the true average power consumption by a dryer, now that I just tried. I do know that the heating element in a dryer is usually rated for 5000 watts+, but you have to keep in mind that it doesn't run at a 100% duty cycle, even on high heat. (I can't find anything that talks about what the typical duty cycle on high heat is, so maybe I'll measure mine the next time I dry something.) I'm pretty sure it would more or less nuke your clothes if the dryer dissipated over 5000 watts all the time. Point being, if an EV charger really does draw 40 amps at 220 volts, that is about twice the real power consumption of a clothes dryer. This is a non-trivial amount of juice. It would be a massive problem if half the automobile-owning households in the US started charging their cars all night long at those rates. It's not just a matter of you not personally having any use for swappable batteries. It's a matter of electricity not being quite as trivial to generate and distribute as you suggest. Nobody that I'm aware of, including me, is trying to spread FUD. I would gay-marry Elon Musk, if I were gay. I wish him all the success in the world. But the numbers behind his prediction simply do not work... unless he has something up his sleeve along the lines of the Better Place concept.

jblow 14y ago
Oh, hey dude. 40 amps at 200v will completely charge a Roadster in something like 7 hours. I don't know how long for a Model S, but it is probably longer. I am only familiar with the day-in, day-out of the Roadster so I will stick to that mostly. So the "charge the car all night (7-8 hours) scenario" only makes sense if you need to charge up the battery 100%, i.e. you were on fumes before you plugged it in, which means you drove 200-240 miles the day before. This may be true for some people but it is not going to be true for most people most of the time. I drive from SF to Berkeley and back most work days, a 25-minute commute each way, and I like to drive it like a sports car, so I use relatively a lot of power for that length of trip. Generally I use about 20% of the Roadster's battery on such a day, so that's probably about 1.5 hours to charge in a 220V outlet. If everyone did that, you would probably want to stagger the charging times, but it is totally doable even with current setups. I do think that there would be some increased power draw and that we would want to beef up our electricity infrastructure a little. But that is pretty different than what I see as a Republican talking point, which is something like "there is no way that the USA can support everyone plugging in their EV, it's impossible." That is not my experience as an EV driver. When I was coming up with the dryer analogy I was just using numbers I pulled off the Internet about what people were measuring their dryer's pull at. It's possible dryers just are not very efficient, I don't know! (Though I thought the whole Energy Star thing was supposed to put pressure on that).
aidenn0 14y ago
And this would be a problem if half the ICE car owning public went out and bought electric cars all in the same month. There will be time to upgrade the distribution grid.
- CamperBob2 14y ago
  Before 2025? Will never happen.