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V2H solution

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
14,270
18,027
Riverside Co. CA
Right on the website you linked, point 2:

===================

Vehicle to Home” is a system that allows you to supply your home with the energy stored in a Nissan LEAF’s battery.

===================

Teslas dont have a bi directional charge port so if the question is "work on a tesla" the answer is "no"
 
Right on the website you linked, point 2:

===================

Vehicle to Home” is a system that allows you to supply your home with the energy stored in a Nissan LEAF’s battery.

===================

Teslas dont have a bi directional charge port so if the question is "work on a tesla" the answer is "no"

The question is did Tesla actually make the charge port 1 way. There are a few ways that Tesla could do it one would be diodes but diodes that can handle those power levels are large an expensive. The other would be current sense if current is flowing the wrong direction it turns off the contactor disconnecting the charge port. I haven't looked at the schematics for the charge port I am just assuming they are using mechanical contactors, If they are using solid state devices then they may have single direction current flow. I am sure they have current sense built in so they could have it cut power if the current flows the wrong direction but I would be surprised if they actually did.

It would require you to spoof the signals to get it to close the contactor between the HV DC bus and the charge port but that is built into the linked device. My guess is it would work but neither Tesla or that company will support it for use with Tesla's.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
14,270
18,027
Riverside Co. CA
I am not technical at all. Sometime in the past 1.5 years, some engineer made a video stating that the model 3 chargeport was bi directional. Then another engineer did a teardown and said the first one was wrong, and the first one agreed that "yes" I was wrong"
=============================

Just as everyone was having such fun imagining the possibilities of a V2G-enabled Tesla (which are indeed intriguing), another electrical engineer, Phil Sadow (aka Ingineerix), challenged Gaxiola’s conclusions in a video. “I don’t believe that’s the case,” says Sadow. He has identified some components on the circuit board in question as diodes, which of course allow current to flow only in one direction. Electric Revs has spoken with Gaxiola, who now admits that he may have been mistaken.


============================

You sound like you have the knowledge to look through that info so figured I would post it for you.
 
I am not technical at all. Sometime in the past 1.5 years, some engineer made a video stating that the model 3 chargeport was bi directional. Then another engineer did a teardown and said the first one was wrong, and the first one agreed that "yes" I was wrong"
=============================

Just as everyone was having such fun imagining the possibilities of a V2G-enabled Tesla (which are indeed intriguing), another electrical engineer, Phil Sadow (aka Ingineerix), challenged Gaxiola’s conclusions in a video. “I don’t believe that’s the case,” says Sadow. He has identified some components on the circuit board in question as diodes, which of course allow current to flow only in one direction. Electric Revs has spoken with Gaxiola, who now admits that he may have been mistaken.


============================

You sound like you have the knowledge to look through that info so figured I would post it for you.
Thanks for posting that. If I had the schematic I could likely go through it and figure out what was going on, I don't have the skill to reverse engineer a board like that. The issue I see with trying to back-feed the charge port with AC is it would only allow for V2G operation, it would not be able to do V2H if the grid was down. There are safety requirements for an interlock to make sure the grid is disconnected before it can supply the house if the grid is down. This is why most solar systems can't power the house is the grid is down. To setup the wall connector to allow it would complicate the install of the wall connector.


The device the OP linked would not be using the PCS the video is talking about. DC fast charging bypasses it by connecting the HV DC bus to the charge port. I haven't found a schematic or wiring diagram for it but from what I can tell Tesla is using mechanical contactors to connect the charge port to the HV DC bus when using DC fast chargers. So while it is still possible for Tesla to turn them off if it senses current flowing the wrong way.

I should look into the communications standards used by the various charge standards. This wouldn't be too difficult to test, just need to spoof the data link commands to say I'm connected to a DC fast charger and see if I have HV DC at the charge port pins. Issue is I much prefer to work with low voltage systems normally under 12V. Although I would still need to test if you can actually pull power from them without it shutting off.
 

Navy93

New Member
Apr 26, 2021
2
0
Denver
Thanks for posting that. If I had the schematic I could likely go through it and figure out what was going on, I don't have the skill to reverse engineer a board like that. The issue I see with trying to back-feed the charge port with AC is it would only allow for V2G operation, it would not be able to do V2H if the grid was down. There are safety requirements for an interlock to make sure the grid is disconnected before it can supply the house if the grid is down. This is why most solar systems can't power the house is the grid is down. To setup the wall connector to allow it would complicate the install of the wall connector.


The device the OP linked would not be using the PCS the video is talking about. DC fast charging bypasses it by connecting the HV DC bus to the charge port. I haven't found a schematic or wiring diagram for it but from what I can tell Tesla is using mechanical contactors to connect the charge port to the HV DC bus when using DC fast chargers. So while it is still possible for Tesla to turn them off if it senses current flowing the wrong way.

I should look into the communications standards used by the various charge standards. This wouldn't be too difficult to test, just need to spoof the data link commands to say I'm connected to a DC fast charger and see if I have HV DC at the charge port pins. Issue is I much prefer to work with low voltage systems normally under 12V. Although I would still need to test if you can actually pull power from them without it shutting off.
A couple of points above that pare presented as facts are incorrect.

I received bids from multiple companies when considering solar panels. Every one provided options to power the house if the grid went down. Grid sensing auto-disconnects have been around for over a decade. V2H is simple and easier than V2G as there are a variety of requirements for V2G that differ by utility company (I.e., there are hundred if not thousands of different standards around the world)

Not to mention for homes that have battery storage in addition to solar generation (or other generation techniques).

Another issue making V2G more complex is that I am effectively giving control of my vehicle battery to the utility company as part of their plans for distribution. The only way that works is if they have direct 2-way communication with the vehicle and the charging (or in this case DIScharging) apparatus. Otherwise, they wouldn’t know if or how much power they could take.

So, to the original discussion, using a Tesla as V2H (especially when Powerwall(s) with a Tesla Gateway are in place would be fantastically simple from a design and logic standpoint, if the vehicle’s charging port allows.
 
Wonder if this, combined with the CHADEMO adapter, would work...

 
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