Cybertruck SuperCharing @ 400V?

[ituner-HF]

I believe that most US Superchargers support only 400V charging, which will cause compatibility issues for the Cybertruck with older Tesla SuperCharging stations.
Is there a workaround to enable 400V DC charging on an 800V system, such as dividing/splitting the battery? Is this feasible or not?

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[Lekrow]

They will need an onboard DC DC converter to step up the voltage.
They will also need a converter to step down from 1000v -> 48v for the non drivetrain electronics.

 

[Roy2001]

I believe that most US Superchargers support only 400V charging, which will cause compatibility issues for the Cybertruck with older Tesla SuperCharging stations.
Is there a workaround to enable 400V DC charging on an 800V system, such as dividing/splitting the battery? Is this feasible or not?

Don't worry, it must be backward compatible.

 

[CyberGus]

They will need an onboard DC DC converter to step up the voltage.
They will also need a converter to step down from 1000v -> 48v for the non drivetrain electronics.

Ummm lol no. A DC/DC converter for 500A would be large, expensive, and inefficient. It would make more sense to split up the pack so as to match in the input voltage. Even better would be to let the SC provide the higher voltage, which would result in less transfer heat and higher overall efficiency.

Of course there will be a step-down to 48v, just like there is now to get 12v.

Or, they could add an alternator...?

 

[ituner-HF]

They will need an onboard DC DC converter to step up the voltage.
They will also need a converter to step down from 1000v -> 48v for the non drivetrain electronics.

a 100-200Kw DC-DC? Way too heavy.

 

[ituner-HF]

Ummm lol no. A DC/DC converter for 500A would be large, expensive, and inefficient. It would make more sense to split up the pack so as to match in the input voltage. Even better would be to let the SC provide the higher voltage, which would result in less transfer heat and higher overall efficiency.

Of course there will be a step-down to 48v, just like there is now to get 12v.

Or, they could add an alternator...?

The alternator seems promising. I think splitting the battery could work as the chassis is 100% isolated from the HV battery terminals. However, balancing a split battery might be difficult. GM has some interesting patents. https://insideevs.com/news/587807/gm-dual-charging-port-patent/

 

[Bill906]

They will need an onboard DC DC converter to step up the voltage.
They will also need a converter to step down from 1000v -> 48v for the non drivetrain electronics.

Although it's technically possible to have a DC to DC converter go from ≈400VDC to 1000VDC, it is unlikely. The size of the device needed to do that at the 350kW level would be, in my opinion, to large.

Do we know for sure the current superchargers cannot handle 1000VDC charging?

I've been wondering about this myself and these are the possibilities I can think of:

1. The superchargers all already can handle 1000VDC charging.
2. The BMS can reconfigure the battery connections putting two halves in parallel instead of in series.
3. On-board DC to DC converter to bring 400VDC to 1000VDC
4. Telsa plans on retrofitting superchargers to be able to handle 1000VDC charging.

I'm hoping for #1 to be true. (I don't know)
One of the main advantages of having 1000VDC is faster charging. So #2 would defeat one of the main reasons for 1000VDC.
I believe number 3 is unlikely do to the converter size needed for fast charging.
I'm hoping not #4 because the SC's I'll be using will not be ones Tesla is likely to convert first.

It might be a combination of #4 and #2. CT battery can reconfigure for 400VDC when needed while the network upgrades.

 

[RandyS]

By the way, according to the TMC forum, there is still an issue with recent Teslas being delivered with a low voltage lithium ion battery that is operated near 16v. Some people have had 12v accessories stop working when plugging into the accessory outlet, and the trailer hitch socket pins on those "16v" cars don't have 12v on that pin (no voltage is present).

So it will be interesting to see what Tesla does with their 48v system and how/if they make 12v available for accessories, etc.

 

[ituner-HF]

By the way, according to the TMC forum, there is still an issue with recent Teslas being delivered with a low voltage lithium ion battery that is operated near 16v. Some people have had 12v accessories stop working when plugging into the accessory outlet, and the trailer hitch socket pins on those "16v" cars don't have 12v on that pin (no voltage is present).

So it will be interesting to see what Tesla does with their 48v system and how/if they make 12v available for accessories, etc.

48V->13.5V@20A. "Legacy support". Maybe. Another option is USB-PD with 48V support (240watt) will practically make the Cigarette Lighter socket absolete. For comparison, Model 3 and Y have USB-PD at 9V, 3A (27WATTS).

 

[CyberGus]

The Megacharger will support 1000A and 1000V.

 

[Ogre]

Do we know for sure the current superchargers cannot handle 1000VDC charging?

I don’t think so.

I think it was in the first of the Semi videos from The Limiting Factor where he broke down the 1000v Supercharger changes and one of the things he showed was the change in the shape of the adaptor to prevent arcing.

It’s been a while since I’ve watched the video so I’d have to review it, but I got the distinct impression that Jordan at least thought the newer design for the plug was required for 1000v to prevent arcing.

4. Telsa plans on retrofitting superchargers to be able to handle 1000VDC charging.

I don’t have a ton to add here, but I wanted to comment on this detail.

About 7-8 months ago I was heading up to Portland to meet someone to purchase some bike stuff. I stopped at the Supercharger in Woodburn there and they had it all torn apart. I talked to the contractor who was doing the work and he said they were adding stalls to the setup.

It was right around the time when the hype around v4 chargers was first bubbling up, so of course I asked him if they were installing v4 chargers. He said they were v3 chargers, but they were “convertible” to v4. I didn’t quite know how to respond to that so I didn’t have a great follow up. I’m not even 100% sure he said “to v4”, but that was the context.

Also…

The BMS can reconfigure the battery connections putting two halves in parallel instead of in series

What effect would this have on the charge rate? Would it just mean it would charge at 250 kW? Or 125 kW? I’ve heard some of the 800v vehicles have absolute crap charging on Tesla chargers because the cars can’t handle 400v well so very curious what the impact would be.

I’m pretty confident charge rates will be tolerable on v3 chargers, but not sure about the details.

 

[Crissa]

Each of the 800v CCS vehicles has a different 'compatibility' mode for charging at 400v CCS stations.

Some actually do have DC-DC boards - and hence, very limited charge rates. Others have ways to split their battery pack so they can handle a higher amount of charge rate.

And some just don't work. I have a friend who tried it on his car, and its software said no, altogether. (Tho his car should work with it with the right firmware, he said.) I know Energica don't work with the Tesla ver 3 CCS stations in Europe (but did with ver 2).

And alas, that's how it is with all stations, since different stations themselves will have different ways of getting to the standard, and different parts working at any one time. It's not Tesla-specific.

-Crissa

 

[JBee]

Just use the motors as a transformer and use a split phase speed controller. There was a thread around here someone posted where they done that. Point is that you don't drive when you charge, so might as well use the motor and speed controller for something.

 

[S.H.Peterson]

All Teslas have onboard DC-DC converters for charging
The CT will be backwards compatible with all superchargers
Tesla will make accessories for the new 48v systems. It should no big thing to get 48v to 12v stepdown converters and install it as the head of a 12v Subsystem but may require dedicated ground leads for anything attached to it

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