Anyone else catch the 800v comment in the earnings call Q1 2022?

[GnarlyDudeLive]

A question about switching from 400v to 800v was posed to team Tesla. Elon and team mentioned it was not worth it to convert the existing vehicles over to 800v for a $100 per car savings. They went on to say 800v would be more useful for heavy load vehicles such as the Semi and CT.

So gleam what you can from that.

Sponsored

 

[Throwcomputer]

Didn't sound like it was a sure thing.. just that it might make more sense for heavy torque uses. But they also did say that it makes no sense because it would require a huge capital investment to completely revamp their supercharger network as well as replacing a whole ton of universal parts across all their product offerings. From that, I took even though theoretically it might make more sense for the CT, it won't happen unless they decide to change everything over in the distant future. They did say it might make more sense in the distant future when the economics of it might justify completely revamping their supercharger network along with all the associated electronics within all of their vehicles.

 

[Ogre]

They are already deploying Megachargers for the Semi and I think they are 400v.

Lots of people seem to think 800v is inevitable, but Musk did not sound convinced.

Maybe because Tesla has so much sunk cost in 400v?

 

[SparkChaser]

It might be better to just have the semi pull up to 2 super chargers and get the 800 juice that way. No change in equipment. Just space the chargers in a way that cars can use them too. Pull thru like a Costco gas station. Multiple connections in pairs and cords long enough to meet in the middle for dual 400v charging the semi. Give it two ports and zoom goes the electrons.
Put it all under a nice solar roof and you are good to go.

 

[GnarlyDudeLive]

They are already deploying Megachargers for the Semi and I think they are 400v.

Lots of people seem to think 800v is inevitable, but Musk did not sound convinced.

Maybe because Tesla has so much sunk cost in 400v?

In reality 800v does make sense just like retiring 12v for the other components in a vehicle. I would day for the future 800v makes sense. When does Tesla want to join the future, then or now is the question?

 

[JBee]

I'm not quite sure what to make of the statement in that its unclear which parts will be effected by it.

Is it 800V for just the charger? If so splitting the 400V pack to allow 2x400V so 800V can come over the charging cable is probably not that hard. Also means they can still charge from 400V too.

But if it means changing the whole vehicle architecture to 800V, being motors, inverter, wiring and charging setup, then yes much more expensive to change the gear and manufacturing lines etc. It could still charge from a split 800V pack at 400V too though.

The main advantage is the cable sizes required, but the inverter electronics are unlikely to be cheaper at a higher voltage either. The more pressing issue, at least here in Australia is that most power distribution lines run 415V and we will need a transformer for a 800V Supercharger.

 

[Crissa]

They are already deploying Megachargers for the Semi and I think they are 400v.

Lots of people seem to think 800v is inevitable, but Musk did not sound convinced.

Maybe because Tesla has so much sunk cost in 400v?

800v requires special hardware that's just more expensive and rare. Most cabling maxes at 600v. You can get 1000v cables, but they cost much more. You end up saving copper but doing a bunch of retooling.

-Crissa

 

[TruckElectric]

They are already deploying Megachargers for the Semi and I think they are 400v.

What makes you think that?

 

[No-ICE]

My understanding is that higher voltage allows the engineers to design systems with thinner copper wire. Perhaps this is where some of the cost reduction comes from.

I have always thought EVs should convert the traditional 12 volt systems to 24 or 48 volts to allow for less copper wire by weight. I believe aircraft engineers do this to reduce weight.

N.ICE

 

[Crissa]

My understanding is that higher voltage allows the engineers to design systems with thinner copper wire. Perhaps this is where some of the cost reduction comes from.

I have always thought EVs should convert the traditional 12 volt systems to 24 or 48 volts to allow for less copper wire by weight. I believe aircraft engineers do this to reduce weight.

N.ICE

Yes.

But if you raise the voltage, you have to deal with more insulation. That's not an issue under 100v, but over 600v you start having some weird effects.

-Crissa

 

[SwampNut]

Yes.

But if you raise the voltage, you have to deal with more insulation. That's not an issue under 100v, but over 600v you start having some weird effects.

-Crissa

+1, over 500-600 gets really weird. Reducing amps is great, up to a point where other issues start.

 

[GnarlyDudeLive]

Would the biggest advantage though be in the charging speed using 800v over 400v? Not a big of a concern if you have a 100KW pack or less but when you get into larger packs, I could see the benefits. Note: even though as mentioned in the earnings call that a $100 per vehicle savings is possible, that would be a cool 150 million $ alone in just CT reservations.

 

[Bill906]

Would the biggest advantage though be in the charging speed using 800v over 400v? Not a big of a concern if you have a 100KW pack or less but when you get into larger packs, I could see the benefits. Note: even though as mentioned in the earnings call that a $100 per vehicle savings is possible, that would be a cool 150 million $ alone in just CT reservations.

I believe it affects charging speeds indirectly. As superchargers get bigger, (150kW, 250kW, 350kW) if the voltage remains constant (≈400V) the current has to go up. I think we are getting to a point that if the current gets much higher the charging cable will become so thick it will be difficult for us weaker people to manage. Plus as current increases loss due to heat increases lowering charging efficiency.

 

[GnarlyDudeLive]

I believe it affects charging speeds indirectly. As superchargers get bigger, (150kW, 250kW, 350kW) if the voltage remains constant (≈400V) the current has to go up. I think we are getting to a point that if the current gets much higher the charging cable will become so thick it will be difficult for us weaker people to manage. Plus as current increases loss due to heat increases lowering charging efficiency.

As I see it that is exactly why 800v has some value, lower heat, and thinner cable required. Unless there is going to be an Optimus at every stall to take care of it and blow on cables to keep them cool, LOL.

 

[SwampNut]

Batteries, charging, and driving range are all about watts expended or gained. Watts is equivalent to horsepower, another measure of work done. Volts is pressure. Most houses run about 60 psi water pressure. We live near a mountain tank get get 100. When our regulator failed, hoses blew up. High voltage is like this. Amps are current, or flow. High amperage creates heat, which increases wire resistance, which creates even more heat, until the wire burns.

volts X amps = watts

You can reduce amps by increasing volts, until that becomes the new problem. As Crissa said, around 600v things get suddenly more challenging. Also, each individual battery cell is about 4 volts (varies by battery chemistry, but close), so no matter what, reductions take place, each of which introduces more heat.

its all a balancing act, and just making one change doesn’t necessarily fix a challenge.

Sponsored