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Backup power - replacing a gas generator for now, V2H in future?

Is backup power important to you?


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DucRider

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No reason to question it. The implication, and there is no doubt about it, is that this EVSE must incorporate the disconnecting means. The much more challenging problem (IMO) is how load shedding is going to be handled.
Not so much of an issue with V2H as it is a backup power source like a generator. When the grid goes down, the backup method for a household - generator or batteries - will be transparent to the utility company.

Utilities are taking baby steps towards V2G which incorporates direct ties to the grid. I am in a pilot V1G program with my utility and they are learning how and when their customers charge and how to interface with them (and their EVSEs) when manipulating charging times/speeds.
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ajdelange

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Is that a typo or is this something distinct from V2G?
 

ajdelange

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Doh! I'm so used to seeing "r2pol" (convert rectangular to polar), "num2char" (convert ASCII code to the character) "sec2date" (Smithsonian time to the date)... that I simply assumed V2H meant vehicle to house.
 

DucRider

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Doh! I'm so used to seeing "r2pol" (convert rectangular to polar), "num2char" (convert ASCII code to the character) "sec2date" (Smithsonian time to the date)... that I simply assumed V2H meant vehicle to house.
Most people asking for V2H (or often even V2G) essentially want to power all or part of their house during an outage. This capability is indeed part of the proposed standards, but not the only feature.
 

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Zoidz

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No reason to question it. The implication, and there is no doubt about it, is that this EVSE must incorporate the disconnecting means. The much more challenging problem (IMO) is how load shedding is going to be handled.
Like all other final details regarding Rivian products, there's alot we don't know and implications are not specs.

Without the specs for the "Modified EVSE", there can certainly be doubt about whether it contains the NEC required mains transfer switch. Basic EVSEs do not contain a DC/AC inverter needed for V2H. "Modified" could imply nothing more than the additional inverter necessary for V2H.

An EVSE integrated mains transfer switch may not be practical for many installations. My service is 80 feet from my garage. This would require 3x160 feet of #2/0 wire ($2000) to use an integrated mains transfer switch. From an installation viewpoint, it makes more sense for the "Modified EVSE" to not contain a mains transfer switch, and use an application appropriate transfer switch.
 

ajdelange

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If it can energize the mains it must be capable of isolating itself from the mains. That doesn't necessarily mean a whole house transfer swtich. The EVSE could connect to a sub panel with the subpanel wired to the main panel through a contactor. Problem there is that you would only be able to serve loads on that subpanel. That's why I wrote that the much more interesting problem is load shedding. Isolating from the utility is pretty easy. All the box needs to do is be able to sense that the grid is missing by any of several algorithms and de-energize a contactor which ties to the service entrance for whole house or a sub panel for partial.

It would have been better if I had said "must incorporate the means to insure disconnection".

Think a bit about how Powerwalls or solar panels with microinverters handle this problem.
 

mike813

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I'm in north florida and live with the occasional power outage. I'd be thrilled to hook up my Rivian and Tesla to some sort of smart box that could use the batteries in the cars to help power the house when the grid goes down. I'm sure we'll see more and more development and solutions in these areas in the coming years, and from what RJ said it sounds like Rivian will be ready.
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