Tesla Superchargers - Gas Station/Convenience Store

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tortuga said:
I would imagine its easier to step down the AC voltage to the DC.
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OK, so that's why the supercharger is designed around a 480VAC supply, rather than a higher voltage, to better back the DC voltages it has to generate (nominally up to 500 VDC).

Cheers, Wayne
 
wwhitney said:
OK, so that's why the supercharger is designed around a 480VAC supply, rather than a higher voltage, to better back the DC voltages it has to generate (nominally up to 500 VDC).

Cheers, Wayne
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Most current EV platforms are 400V nominal. Porsche and Kia/Hyundai have 800V platforms.
 
wwhitney said:
OK, so that's why the supercharger is designed around a 480VAC supply, rather than a higher voltage, to better back the DC voltages it has to generate (nominally up to 500 VDC).

Cheers, Wayne
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retirede said:
Most current EV platforms are 400V nominal. Porsche and Kia/Hyundai have 800V platforms.
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ITs an interesting question if you think about large scale EV charging infrastructure, what AC input voltage is ideal for the efficiency and cost of the charging equipment? FWIW, a three phase bridge results in a DC bus voltage of about 1.35 the AC voltage, which would be 648 volts DC from 480 AC. Not sure if that is relevant to the actual power electronics topology of these things.
 
electrofelon said:
ITs an interesting question if you think about large scale EV charging infrastructure, what AC input voltage is ideal for the efficiency and cost of the charging equipment? FWIW, a three phase bridge results in a DC bus voltage of about 1.35 the AC voltage, which would be 648 volts DC from 480 AC. Not sure if that is relevant to the actual power electronics topology of these things.
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Very interesting. I see 350 KW charging stations out there. But a 400V vehicle won’t charge any faster on them that it will on a 150 KW. Because current is the limiting factor. 400A is the max.
But you can plug either a 400V car or an 800V car into a 350 station and it works. The 800V car and the 400V car can each get 400A at the correct voltage. I haven’t researched how this is accomplished. Something on my list.
 
retirede said:
Most current EV platforms are 400V nominal. Porsche and Kia/Hyundai have 800V platforms.
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OK, but my understanding is that the DC Fast Chargers are generally 500V nominal (or 1000V nominal). So if a station advertises itself as 100kW, that means it can do up to 200A at up to 500V. If you plug in and your battery is at 350V, then the most you'll get from it is 70 kW, if your EV's battery management firmware has been programmed to allow that high a charge rate (based on the EV's capacity and state of charge).

Cheers, Wayne
 
Fred B said:
and so how is one to bid such requirement, unknown number of rods to get down to 25 Ohms. And what are the soils conditions and weather conditions at time of installation or GR testing as it will impact the test results as well.
(It's been raining for a week straight when we did the rods and initial testing, now it's been dry for a month and the AHJ now says its over the 25 ohm mark.)
I saw a M.H. video that demonstrated this and one test got quite a few rods to get to below 25 ohm
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"Base bid includes up to 4 additional rods, each rod thereafter to be supplied and installed at a cost of $XXXX."
 
Fred B said:
and so how is one to bid such requirement, unknown number of rods to get down to 25 Ohms. And what are the soils conditions and weather conditions at time of installation or GR testing as it will impact the test results as well.
(It's been raining for a week straight when we did the rods and initial testing, now it's been dry for a month and the AHJ now says its over the 25 ohm mark.)
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It was lazy engineering to specify the resistance rather than the design of the GE system, but the time to get clarification and correction to the design is/was before the beginning of construction.
 
wwhitney said:
OK, but my understanding is that the DC Fast Chargers are generally 500V nominal (or 1000V nominal). So if a station advertises itself as 100kW, that means it can do up to 200A at up to 500V. If you plug in and your battery is at 350V, then the most you'll get from it is 70 kW, if your EV's battery management firmware has been programmed to allow that high a charge rate (based on the EV's capacity and state of charge).

Cheers, Wayne
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Agree. The charge station has be capable of a higher voltage than the battery in order to charge.
 
ggunn said:
It was lazy engineering to specify the resistance rather than the design of the GE system, but the time to get clarification and correction to the design is/was before the beginning of construction.
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To engineer it, there would need to be a soil resistivity study. I've never priced it up, but I would imagine it would cost more to do that than to drive a couple more ground rods.
 
I wonder how they are going to meter the home chargers for the fuel tax. Might be easier to tax the vehicle by miles driven
 
Joethemechanic said:
I wonder how they are going to meter the home chargers for the fuel tax. Might be easier to tax the vehicle by miles driven
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Various states are implementing things. Some just tack on additional yearly registration fees. Others are considering or implementing a per-mile charge (Utah). One state (can’t remember which) will give you a dongle to record and charge by the mile with an option to pay a fixed yearly amount if you don’t want the monitor on your car.

The last time Illinois raised the gas tax, they considered a per-mile charge for all vehicles.

The pros and cons of all these schemes could be debated endlessly.
 
They could just turn every road into a toll road installing EZ-Pass scanners everywhere.
Get rid of tax on gas, then the gas companies can just jack their prices to match the taxed price and make even more profit. They did that here when the state had a gas tax holiday during the covid and the price never did drop, it only went up when the holiday ended.
 
Joethemechanic said:
Here is one to think about. Plug in hybrid. Did the energy come from already taxed liquid fuel, or from untaxed electricity, or a mix of both?
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Here’s another view. Everyone benefits from highway infrastructure even if you don’t drive, so just charge everyone a flat rate. Eliminate all the jockeying and red tape.
 
retirede said:
Here’s another view. Everyone benefits from highway infrastructure even if you don’t drive, so just charge everyone a flat rate. Eliminate all the jockeying and red tape.
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That sounds reasonable. We don't have a separate tax for every line item in the budget; why should highway infrastructure be separate?
 
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