Exporting or importing DC directly to a car with V2X DC, let's connect all the things together

[Seattle]

Powerwall 3 can connect to additional batteries with "DC Expansion" using DC, but nothing else afaict. Wouldn't it be cool if you could connect your EV and use it as DC too?

• Today Rivian announced their original vehicles (aka R1T, R1S first revision, and the new revisions too) have 24kw 2-way DC, yet to be enabled, also haven't clarified standards support. The recently announced revision 2 vehicles have an onboard 10.5 kw ac inverter, so probably could do v2x with that on AC. But both rev 1 and rev 2 and hopefully later vehicles have 24kw 2-way DC. Currently there doesn't appear to be a DC charger to connect it to. Rivian talks about running your house off your vehicle, v2h, and there must be a planned DC to AC "charger" outside of the car with all the needed equipment, getting closer to the f150ev home power system. Maybe one day the dcbel.energy DC charger could do this.

I want to try to figure out when/if this forthcoming DC charging could work with powerwalls. Many of the pieces are there, but what's the standards support, what will Tesla or Rivian support. The short answer is probably no one knows, it's not announced.

It would be nice if powerwalls could start supporting V2X DC connected to vehicles that support it too. This is an additional step requiring there is a way to directly access your EVs battery getting DC out. This seems to be one of those things that has potential but the pieces are never quite finished. Presumably Rivian will sell separate DC chargers or an inverter/charger.

Any thoughts? Imagine a home system where you have powerwalls, you have DC Expansion. You have solar. Then you get a (not yet available?) charger that supports AC and DC. You can now add the battery from your vehicle to your "DC network", similar to the DC expansion strategy. Now you can have a kind of "temporary battery" from cars plugged in at home. Or imagine another use case, no Powerwall or solar, but when your car is plugged in it can run your house power in an outage (with basically similar equipment to the f150ev needed to backup your home power - DC though in this case?).

 

[miimura]

The main problem with a DC micro-grid is that there are no standards to follow. Any company that wants to introduce an ecosystem of products like that has to invent a scheme to regulate power flows among nodes in the system. DC-DC converters also have to be developed to be deployed at each node to execute the power flow regulation. AC micro-grids are well established. Until there are mature cost optimized products on the market, it will be hard to rationalize the cost of the DC system based on the slightly higher efficiency that it delivers.