[Rant] locals clogging the Highland Park, IL supercharger

[AZ Desert Driver]

As I fumble through the electrical problem....The car battery wiring would need to have a bypass installed to allow the DC in the battery to be taped for feeding into the inverter mounted on the wall beside a Powerwall. If one just plugged into the recharge socket - it would be on the wrong side of the charger/inverter that fuels the car battery. So, the car would have to be modified to tap into its DC source. Would Tesla design/build this bypass? Would an aftermarket shop dink with the car and install the bypass (without Tesla getting twitchy about warrantee). My imagination has one 14-50 wire to charge, then unplug the charge and flip a DC switch on the car to feed a wall mounted inverter that feeds the household. Fill the car once/week when Time-of-use is low, feed the household off the car when the car is not being tasked for driving and TOU rates are high. Investment is Inverter and bypass plumbing.
Anyone care to reinforce this rough plan?

 

[stopcrazypp]

As I fumble through the electrical problem....The car battery wiring would need to have a bypass installed to allow the DC in the battery to be taped for feeding into the inverter mounted on the wall beside a Powerwall. If one just plugged into the recharge socket - it would be on the wrong side of the charger/inverter that fuels the car battery. So, the car would have to be modified to tap into its DC source. Would Tesla design/build this bypass? Would an aftermarket shop dink with the car and install the bypass (without Tesla getting twitchy about warrantee). My imagination has one 14-50 wire to charge, then unplug the charge and flip a DC switch on the car to feed a wall mounted inverter that feeds the household. Fill the car once/week when Time-of-use is low, feed the household off the car when the car is not being tasked for driving and TOU rates are high. Investment is Inverter and bypass plumbing.
Anyone care to reinforce this rough plan?

Any DC charging standard already has a built in DC bypass for charging the car, so V2G support is almost trivial. CHAdeMO has V2G support (although it requires an external box), as does the CCS standard (built into the standard). Tesla can certainly add it to their standard (or more likely they will get it after they adopt the next version of the CCS standard, which they seem poised to do with their recent membership in the CCS Charin group as a core member).

 

[AZ Desert Driver]

Any DC charging standard already has a built in DC bypass for charging the car, so V2G support is almost trivial. CHAdeMO has V2G support (although it requires an external box), as does the CCS standard (built into the standard). Tesla can certainly add it to their standard (or more likely they will get it after they adopt the next version of the CCS standard, which they seem poised to do with their recent membership in the CCS Charin group as a core member).

OK - I think you said that Model S(and probably a Model 3) have already some form of V2G support/bypass where battery power can be tapped to supply home power via an inverter. I'm getting optimistic that I can use my Model 3 as a power wall and I only need to buy an inverter. I really did not want to poke holes in my car. Can you suggest an inverter that might serve this purpose? Can you enlighten me as to how to activate the V2G circuit?

 

[stopcrazypp]

OK - I think you said that Model S(and probably a Model 3) have already some form of V2G support/bypass where battery power can be tapped to supply home power via an inverter. I'm getting optimistic that I can use my Model 3 as a power wall and I only need to buy an inverter. I really did not want to poke holes in my car. Can you suggest an inverter that might serve this purpose? Can you enlighten me as to how to activate the V2G circuit?

Not exactly. There is no V2G support in the Model S, nor do I expect there to be in the Model 3. It explicitly voids your warranty in the Model S and I expect the same in the Model 3.

What I am saying is that DC charging (whether, CHAdeMO, CCS, or superchargers) already use a DC bypass. The way a DC charger charges the battery is by directly connecting to the battery, bypassing the onboard charger (which takes AC). It would be relatively trivial for Tesla to add V2G support, but not necessarily for you to do so.

The way for someone at home to do it would be to fool the car into thinking it is charging at a DC charger, and then rather than charging the battery, you drain power from it (since you now have a direct connection to the battery). However, depending on how the safety mechanisms are designed, it might cut you off. Once again, however, this voids your warranty. You also need know how the supercharger protocol works (which no one outside Tesla really does, except perhaps wk057).

 

[AZ Desert Driver]

Not exactly. There is no V2G support in the Model S, nor do I expect there to be in the Model 3. It explicitly voids your warranty in the Model S and I expect the same in the Model 3.

What I am saying is that DC charging (whether, CHAdeMO, CCS, or superchargers) already use a DC bypass. The way a DC charger charges the battery is by directly connecting to the battery, bypassing the onboard charger (which takes AC). It would be relatively trivial for Tesla to add V2G support, but not necessarily for you to do so.

The way for someone at home to do it would be to fool the car into thinking it is charging at a DC charger, and then rather than charging the battery, you drain power from it (since you now have a direct connection to the battery). However, depending on how the safety mechanisms are designed, it might cut you off. Once again, however, this voids your warranty. You also need know how the supercharger protocol works (which no one outside Tesla really does, except perhaps wk057).

I just did some quick calculations - the difference between peak and off peak (in my market) ranges from $0.02 to $0.03 /kwh. So if I spent $3,000 for a powerwall system that shifts 10 kwh - I save 30 cents. If this happens daily, it takes 10,000 days to breakeven. Wow, a 27 year payout. And I risk blowing a $42,000 car to save $0.30.

I just watched a video of a Tesla VP in Norway discussing V2G (among other topics) and I came away with - some day it will be there, but that day is not today.

From here, I think I have asked the question about powerwall and concluded that it is well understood and not a thing to be pursued now. Thanks for you help stopcrazypp.

 

[ohmman]

I just did some quick calculations - the difference between peak and off peak (in my market) ranges from $0.02 to $0.03 /kwh.

Wow.

In my market, it's $0.11466/kWh off-peak, $0.44402/kWh on-peak (summer rates). So you can see that the upside is much larger - which is why Powerwall rollouts may be a lot more attractive here.

 

[tomas]

Wow.

In my market, it's $0.11466/kWh off-peak, $0.44402/kWh on-peak (summer rates). So you can see that the upside is much larger - which is why Powerwall rollouts may be a lot more attractive here.

Yes, very market and rate plan dependent. Also makes sense if you have solar so you can lessen or eliminate grid dependence.

 

[AZ Desert Driver]

Yes, very market and rate plan dependent. Also makes sense if you have solar so you can lessen or eliminate grid dependence.

I have room on my roof for solar, but the local Utility is so anti-solar that there is no margin to make it economical. Basically, I pay my current rates, plus 1 to 5 cents per kWh for electing to have my juice delivered by solar. How I know the extra fee bought special power - gee, I guess my water boils differently, perhaps Light Water? Perhaps someday the forces won't be fighting each other and the decision won't be political. But that day is not today.

 

[jgs]

Not exactly. There is no V2G support in the Model S, nor do I expect there to be in the Model 3. It explicitly voids your warranty in the Model S and I expect the same in the Model 3.

By the way, one reason it's rational for Tesla to do it this way is their very generous battery warranty. It's well-known that frequent and deep cycling of batteries wears them out. It's one thing for Tesla to accept the warranty risk of covering batteries used exclusively for driving, quite another if the car battery is being used to power a home.

When I realized this I became quite a bit less grumpy about the lack of V2G.

 

[tomas]

I have room on my roof for solar, but the local Utility is so anti-solar that there is no margin to make it economical. Basically, I pay my current rates, plus 1 to 5 cents per kWh for electing to have my juice delivered by solar. How I know the extra fee bought special power - gee, I guess my water boils differently, perhaps Light Water? Perhaps someday the forces won't be fighting each other and the decision won't be political. But that day is not today.

I do not understand this. If you have solar panels, you will consume your generated power first. If you have powerwall, excess generation up to capacity of powerwall is stored. Your meter doesn't know any of this, so how can utility charge you for what you use/store that never hits the meter?

 

[ohmman]

I do not understand this. If you have solar panels, you will consume your generated power first. If you have powerwall, excess generation up to capacity of powerwall is stored. Your meter doesn't know any of this, so how can utility charge you for what you use/store that never hits the meter?

I think @Desert Driver is talking about a solar opt-in plan offered by the utility, not rooftop PV.

 

[Ryanhdd]

I read about the first 4 pages of this thread and I have one question and a statement.. first I do not own a tesla... yet. second i thought it only took 20mins to charge to 80% which is what is needed. So why are there people even at the charger for hours? Thanks

 

[jgs]

So why are there people even at the charger for hours? Thanks

They're jerks.

 

[ohmman]

They're jerks.

Or, they're just the same people who push their grocery carts down the middle of the lane for the entire length of it, while you crawl behind them in your car. That is, they're unaware of their surroundings.

 

[AZ Desert Driver]

So - I have two choices. #1 - buy $25,000 of panels or buy from grid...99 year payout. #2 - buy off someone else panels that feed the grid and the power I use is priced at a few pennies above grid price. How do I know my power came from that source - or do I just get fuzzy feelings?
Either way - solar and powerwall seem uneconomic to me at this juncture.

 

[tomas]

So - I have two choices. #1 - buy $25,000 of panels or buy from grid...99 year payout. #2 - buy off someone else panels that feed the grid and the power I use is priced at a few pennies above grid price. How do I know my power came from that source - or do I just get fuzzy feelings?
Either way - solar and powerwall seem uneconomic to me at this juncture.

Have you done the real math on solar panels? I've never seen payback longer than 12 years. Especially in area where you have copious sun and probably flog the ac.

 

[ThosEM]

By the way, one reason it's rational for Tesla to do it this way is their very generous battery warranty. It's well-known that frequent and deep cycling of batteries wears them out. It's one thing for Tesla to accept the warranty risk of covering batteries used exclusively for driving, quite another if the car battery is being used to power a home.

When I realized this I became quite a bit less grumpy about the lack of V2G.

I take you your point but don't you think this might be relevant to Powerwalls too?

 

[dgpcolorado]

I take you your point but don't you think this might be relevant to Powerwalls too?

My understanding was that Powerwalls used a different chemistry than the car batteries and that one reason was improved cycling life. Perhaps someone here knows more about it.

 

[kort677]

could the mods change the title of this thread? it is no longer relevant to the original topic

 

[ohmman]

could the mods change the title of this thread? it is no longer relevant to the original topic

This conversation is going on in multiple subforums. I'd love to see all of them merged into the Charging Standards and Infrastructure subforum so we could have a single discussion about Supercharger use/misuse. There's a vibrant conversation about the potential for Supercharger congestion going on in Model 3, and it addresses a lot of the same issues.