V2X / V2L patents by Rivian

[MoreTrout]

Right now I am charging my R1T and the clothes dryer is running. And it is very hot, so the downstairs and upstairs air conditioners are running. I am pulling 23.3 kW from the power company. I can never run my house on solar. I don't even have an electric range or electric water heater - both are NG. Yet 23.3 kW.

I am planning to get solar to power a few circuits, but whole house solar will never happen in this house.

I would wager it is safe to assume you have a 48A 11.5 kW charger. One of the nice things about the current smart unidirectional chargers that will also be true of the bidirectional chargers in a system like Enphase is that they can be set to only deliver the excess solar to the vehicle. Two AC units should only be between 4-5 kW. So a moderately sized array should handle that, all lights, and other low power baseload with extra to send to the truck. When other high loads like dryers/ovens, etc are on, they are not drawing their peak the entire time. So an 8-10 kW solar array and a bidirectional charger can handle high peak loads. The DC one RJ said they are working on will provide as much as 20-24 kW. It then becomes a matter of time. A family of 8 probably can run a dryer nearly all day on laundry day(s). A retired couple like us, the dryer is only used 1 or 2 days a week. I also have the luxury of charging at peak daylight.

If you approach it from a net energy use, than the solar can and will produce as much as the vehicle and the whole house uses. I have averaged about 17,000 mi/yr since I got the truck. My 8kW array generated 11.2 MWh last year. My total consumption for the year was 13.7 MWh. Even though the net from the grid was only 2.6 (some rounding in one or more of those), I imported 8.8 MWh from the grid and exported 6.3 MWh. Where I live we still have 1:1 net metering, and have a single 24 hour rate, so the TOU doesn't mean anything to me financially. But the excess in both directions will drop radically with a bidirectional charger.

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[MoreTrout]

It seems to me you are on the right track and certainly the truck can act as the generator. The problem I see is the Enphase won't be able to monitor the charge on your truck's battery, so it could run it down to dead. You definitely don't want a dead HVB. That is bad news.

True. But I would think the software in the truck could set a lower limit to where it won't send power. Then the controller may look for it, but it just wouldn't be available and would then just turn to the grid.

The more likely issue I thought of is that a direct connection from the car to the controller would only be capable of sending power into the controller. The controller itself, or rather the AC input spot being used I don't think is designed to be a power output. That's somewhere in the brains and output side of the controller, and would therefore require a separate output back to the vehicle. Therefore, the middle man, i.e. bidirectional charger is still going to be necessary.

Once my installer gets the permit approval for my solar expansion sometime in the next couple of months, I'll see what they think when they are here. They are Enphase certified installers and do EVSE installations too. I'll try to remember to post an update.

 

[mkhuffman]

I would wager it is safe to assume you have a 48A 11.5 kW charger. One of the nice things about the current smart unidirectional chargers that will also be true of the bidirectional chargers in a system like Enphase is that they can be set to only deliver the excess solar to the vehicle. Two AC units should only be between 4-5 kW. So a moderately sized array should handle that, all lights, and other low power baseload with extra to send to the truck. When other high loads like dryers/ovens, etc are on, they are not drawing their peak the entire time. So an 8-10 kW solar array and a bidirectional charger can handle high peak loads. The DC one RJ said they are working on will provide as much as 20-24 kW. It then becomes a matter of time. A family of 8 probably can run a dryer nearly all day on laundry day(s). A retired couple like us, the dryer is only used 1 or 2 days a week. I also have the luxury of charging at peak daylight.

If you approach it from a net energy use, than the solar can and will produce as much as the vehicle and the whole house uses. I have averaged about 17,000 mi/yr since I got the truck. My 8kW array generated 11.2 MWh last year. My total consumption for the year was 13.7 MWh. Even though the net from the grid was only 2.6 (some rounding in one or more of those), I imported 8.8 MWh from the grid and exported 6.3 MWh. Where I live we still have 1:1 net metering, and have a single 24 hour rate, so the TOU doesn't mean anything to me financially. But the excess in both directions will drop radically with a bidirectional charger.

The additional challenge for my house is our HOA. I cannot put panels on the front, so there is only the rear, which faces east. It gets good sun for a much shorter period of time than if I had a roof facing south, or if I could put panels on both sides of the roof.

I had Dominion Energy do a estimate for my house and if I covered every allowed surface, I could get 8772 kWh of production with 25 panels. It would offset 34% of my electric bill.

I could replace the electric clothes dryer with NG and put in a higher efficiency HVAC system. I doubt it would be able to get the bill offset to 50% with those changes.

So my approach is just to get a system that can run my security system, home network, NG range, the kitchen light circuit (with is all LED) and all the refrigerators (x3). Ideally it would be off grid except for when the battery runs out and then pull from the grid.

Those circuits are the most critical in a power failure, so they would be the ones I want to always be working. For long outages I would fire up the NG generator anyway, but at least part of the house would always be on without any generator intervention.

Power failures are rare here. Sometimes it goes out during a bad thunderstorm, but it comes back on fairly quickly. Years ago we had a hurricane hit and we were without power for five days. That was horrible. I never want to experience that again. Of course if I had panels on the roof they might have been damaged during the hurricane anyway. LOL.

 

[SANZC02]

If anyone is already familiar with Enphase based solar systems or is willing to look at a document I'll attach, I was hoping someone might be able to tell me if I'm thinking about this right.

I currently have an Enphase based 8kW solar array. The permit application for the expansion was recently submitted, and in a couple of months will be upgraded to 12.1 kw. My R1T is approaching it's 3rd birthday, and we're on the list to add an R2. So all options RJ described in that video will be on the table for me.

When I did the initial solar installation in 2022, I did the sunlight backup option without a battery. I knew there wasn't much practical use to the solar only backup which is limited to 4 circuits and ~30% of the array output during a grid outage. But I knew then my R1T was about to arrive and bidirectional charging would be in the future. Since you need an Enphase controller for either sunlight backup or a backup battery or generator, my thinking was that the controller wasn't going to get cheaper for when I actually did need it, so included it in the initial installation. (inflation has since validated that decision)

Here is the link to the full guide for those that like to look at diagrams and specs, but the key wording I see is that the controller accepts "third party AC-standby generators to be connected to your home". https://enphase.com/download/understanding-sunlight-backup-system-homeowners
I recall my installer showing me the slot where a generator would get connected, and I'm almost positive he said it would accept any AC power source.

So if I am hearing what RJ said in that interview correctly, with the R2 having onboard AC-AC, in theory I could connect the vehicle to the Enphase controller with no additional interface/equipment required. I already knew the R1T would need the external inverter. The big question would be if the Enphase controller can preferentially draw from the vehicle instead of the grid when demand exceeds my solar output. It obviously draws from both when the grid is down, but I want it to look to the vehicle first to minimize or eliminate any use of the grid.

Of course Enphase has promised and delayed their own bidirectional charger for 3 years now. It's due in 2026. I would be 99.99% sure they make it to work with any EV from any manufacturer. I'm far, far less confident they would make Rivian's or any other 3rd party bidirectional charger compatible with their architecture. But it would be best if the R2 made any external device unnecessary.

Am I thinking about this correctly or am I way off?

I think the reason everyone has been dragging their feet on providing solutions is they were waiting on the standards to be published.

NEMA published them this past February so I’m probably being optimistic but hope that all of the solutions we should see coming out will be standards based capable of playing well with each other.

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