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Discussion Starter #1
Does anyone know what limits the maximum charging power being offered by the various UK Supercharge networks ?

Tesla V2 - up to 150kW
Tesla V3 - up to 250kW
Gridserve Type 1 - up to 175kW
Gridserve Type 2 - up to 350kW
Ionity - up to 350kW

I am looking for any obvious reason why these are stated as the upper thresholds. Technical ? Regulation ? Safety ? Market ?

Thank you.
 

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They are different systems and have different Amp limits.

I believe the maximum you can charge a Model 3 on Ionity is 200 kW.
 

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Thanks @cah197. Yes, I get that and am aware that this may exceed many on-car DC charging limits, but I was intrigued why 150kW, 250kW and 350kW came up. Is there some natural GRID, distribution, cable or equipment limit that applies ?
 

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Thanks @cah197. Yes, I get that and am aware that this may exceed many on-car DC charging limits, but I was intrigued why 150kW, 250kW and 350kW came up. Is there some natural GRID, distribution, cable or equipment limit that applies ?
Those figures should be considered the theoretical max power or rated power of the chargers. This would be max volts at max amps.

In the real world battery pack voltages vary depending on SOC and are lower than 500 volts.

CCS 2 requires liquid cooled cables to deliver higher powers, which may be a limitation on some units.

In practice most EVs can only charge up to 150 kW in any case - many are much less.

Only the Model 3 and Porsche Taycan can do 250 kW in the real world. Not sure how realistic 350 kW is for the Taycan in normal use.
 

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It is limited by current battery tech. 250-350kw is the max any current cars can take and is also the sweet spot for getting a grid connection at a reasonable price and having 3-4 stalls at each location.

I'd imagine 350kw is probably going to become a standard which I think most people will be happy with.

Lorries obviously will get 1000+kw but they will have their own networks I'd imagine.
 

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The grid is obviously one limiting factor but if you're asking why those specific values it's because of the equipment design.

The higher the energy the more expensive your hardware becomes for reliability and safety reasons. The software then likely caps it at a convenient marketing value (much like many engines are marketed at stepped power points).

The only regulation is based on the grid ability to deliver the power, and the safety aspects are mitigated in design.
 

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Discussion Starter #8
I'd imagine 350kw is probably going to become a standard which I think most people will be happy with.
Yes, I agree. Although I have read serious US government studies talking about 400kW+ charging in line with a 10 minute fill-up requirement. (Clearly planning for a possible future...)
 

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Discussion Starter #9
Thank you for your feedback everyone. It sounds like there is no obvious limit other than that cars have not got to such high charge rates yet.
 

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Yes, in general. But Taycan is 800V and I think other cars offering similar range will follow at 800V+.
Which cars are you thinking about?

Interestingly the Taycan stats a maximum charging rate of 270 kW, but you need the 350 kW charger to achieve this. Go figure.

The Taycan battery is 800 volts, but charges at 400 volts and then converts to 800 volts via the onboard DC-DC charger.
 

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Which cars are you thinking about?

Interestingly the Taycan stats a maximum charging rate of 270 kW, but you need the 350 kW charger to achieve this. Go figure.

The Taycan battery is 800 volts, but charges at 400 volts and then converts to 800 volts via the onboard DC-DC charger.
Yep agreed. But the fact remains that a 800V battery halves the charge current to the cells (however you get to it) which means you can charge twice as quick.
 

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I think I found my answer in the Porsche diagram below. 100kW is the limit of 400V charging with conventional Li-Ion battery cell architectures. Apply smart battery charging (SOC, level of charge and temperature dependent ?) and you can get to 150kW before exceeding a 350A plug. (So that is the Tesla V2 charger.) Move to 800V and you can get to 220kW with conventional battery cells. (So that explains the the Tesla V3 charger thinking I think.) Apply smart battery charging at 800V (SOC, level of charge, temperature dependent and cooling dependent ?) and you can exceed 220kW. In a second diagram in the same report Porsche appear to indicate how 350kW came about: it is the charge power required to get a BEV from Berlin to Lindau (i.e. across Germany) with only a 10% increase in travelling time compared to an ICE. Interestingly a US report I read came up with 400kW for a 10 minute charge over a typical long distance route - so the two sides of the pond are not too far apart in terms of the ideal target.

(The full Porsche article is here: https://www.porscheengineering.com/filestore/download/peg/en/pemagazin-01-2016-artikel-e-power/default/09d75d4f-3e8d-11e6-8697-0019999cd470/e-power-–-New-Possibilities-with-800-Volt-Charging-Porsche-Engineering-Magazine-01-2016.pdf)

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I think I found my answer in the Porsche diagram below. 100kW is the limit of 400V charging with conventional Li-Ion battery cell architectures. Apply smart battery charging (SOC, level of charge and temperature dependent ?) and you can get to 150kW before exceeding a 350A plug. (So that is the Tesla V2 charger.) Move to 800V and you can get to 220kW with conventional battery cells. (So that explains the the Tesla V3 charger thinking I think.) Apply smart battery charging at 800V (SOC, level of charge, temperature dependent and cooling dependent ?) and you can exceed 220kW. In a second diagram in the same report Porsche appear to indicate how 350kW came about: it is the charge power required to get a BEV from Berlin to Lindau (i.e. across Germany) with only a 10% increase in travelling time compared to an ICE. Interestingly a US report I read came up with 400kW for a 10 minute charge over a typical long distance route - so the two sides of the pond are not too far apart in terms of the ideal target.

(The full Porsche article is here: https://www.porscheengineering.com/filestore/download/peg/en/pemagazin-01-2016-artikel-e-power/default/09d75d4f-3e8d-11e6-8697-0019999cd470/e-power-–-New-Possibilities-with-800-Volt-Charging-Porsche-Engineering-Magazine-01-2016.pdf)

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Pure Porsche propaganda, I fear.

The Model 3 can charge at 250 kW and has a 350 volt nominal battery pack. So something like 700 amps on a V3 Supercharger.

The Tesla adjusts charge rate based on SOC (like most EVs) and employs active cooling of the battery and cable. So nothing new there.

Porsche seem to have sacrificed efficiency, so likely slower on a road trip than a Model 3, even if they could achieve 350 kW charging.
 
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