MASTER THREAD: Powering house or other things with Model 3

[miimura]

Is there anything stopping us from plugging a small 12v inverter into the cigarette lighter or directly to the 12v battery to power some small <1800 watt load? Would the HV battery keep the 12v charged automatically?

The lighter socket is the right place to take power as long as you keep it below 10A. So, more like 100W AC load max (120W DC).
If you need 1,800W, you need to take it from the PCS terminals under the back seat and make sure that you don't have any significant surge loads. Also, that's like 150A DC, so make sure you use some nice fat cables.

Taking power directly from the 12V on a 3 or Y can throw errors because the car is monitoring the 12V battery charging current. On Legacy S & X you can take power directly from the battery because the car can't tell where the power is going.

 

[FlatSix911]

The lighter socket is the right place to take power as long as you keep it below 10A. So, more like 100W AC load max (120W DC).
If you need 1,800W, you need to take it from the PCS terminals under the back seat and make sure that you don't have any significant surge loads. Also, that's like 150A DC, so make sure you use some nice fat cables.

Taking power directly from the 12V on a 3 or Y can throw errors because the car is monitoring the 12V battery charging current. On Legacy S & X you can take power directly from the battery because the car can't tell where the power is going.

Thanks for clarifying the difference in circuit design between the 3/Y and the S/X. I draw power directly from the 12V battery on my Model S.

 

[miimura]

Thanks for clarifying the difference in circuit design between the 3/Y and the S/X. I draw power directly from the 12V on my Model S.

Classic Model S (ones with the nosecone) also have the jump post that can support 50A. Those cars have the 12V battery buried way back by the bulkhead. The new refresh S & X with the lithium 12V are much harder to connect to because they don't have traditional battery posts and they also have the same limitations as the 3 & Y because they also did away with the traditional fuse box in favor of the software controlled Vehicle Control modules.

 

[Candleflame]

It’s pretty appalling that the cars are not designed to externally power anything of substance eg your house or sound system or caravan. I thought the fundamental ideology for EVs was to have the power going both ways when required.
I’m sure I’ve seen other EVs being demo’d to do this eg The Leaf in Japan a few years ago. Charge it up when grid rates are low then plug it in as a power source during peak times....

It endagers teslas own km based warranty. So why would they do that. Also battery cooling could be an issue without the radiator getting wind

 

[Dave EV]

It endagers teslas own km based warranty. So why would they do that. Also battery cooling could be an issue without the radiator getting wind

Battery cooling is not an issue - the batteries can handle Supercharging at rates far higher than any V2G application might handle. After all, a ~13 kWh Powerwall can handle 5 kW, and it's cooling system has far less capacity than a car.

If the onboard charger were designed to be bi-directional, they would probably design it to handle up to ~10 kW, same amount of power that it converts AC to DC and it would have similar efficiency in the other direction, so similar cooling loads. When AC charging up to ~10 kW, it's very rare to need to do anything by circulate coolant.

 

[Candleflame]

Battery cooling is not an issue - the batteries can handle Supercharging at rates far higher than any V2G application might handle. After all, a ~13 kWh Powerwall can handle 5 kW, and it's cooling system has far less capacity than a car.

If the onboard charger were designed to be bi-directional, they would probably design it to handle up to ~10 kW, same amount of power that it converts AC to DC and it would have similar efficiency in the other direction, so similar cooling loads. When AC charging up to ~10 kW, it's very rare to need to do anything by circulate coolant.

supercharging degradades the battery while they being "cooked" - but cars dont supercharge all day long and the process is energy intensive (not that it matters as you are hooked up to a high energy powersource) 10kw is probably not too bad but it does affect the battery and tesla wont have cars heavily used as storage batteries and then replace them due to failure.

 

[cali8484]

supercharging degradades the battery while they being "cooked" - but cars dont supercharge all day long and the process is energy intensive (not that it matters as you are hooked up to a high energy powersource) 10kw is probably not too bad but it does affect the battery and tesla wont have cars heavily used as storage batteries and then replace them due to failure.

So Ford, Hyundai, Nissan, etc. can do it under warranty but Tesla can't figure it out?

 

[Candleflame]

So Ford, Hyundai, Nissan, etc. can do it under warranty but Tesla can't figure it out?

they have likely already gimped batteries or dont realize the consequences of allowing their drivers to do this or figure that not many drivers will ACTUALLY do this so it doesnt matter too much.

Or their battery warranty is very low - most manufacturers offer less lenght and less kms than tesla. and tesla naturally allows larger access to the battery exposing the battery to more degradation. I.e. audi etron only allows you to access 90% of the battery.

 

[stopcrazypp]

So Ford, Hyundai, Nissan, etc. can do it under warranty but Tesla can't figure it out?

Nissan used to have a pretty poor capacity warranty (70% in 5 year / 60k miles), although they were the first out of necessity due to rapid battery degradation in early Leafs, although they have since improved to match the industry standard 8 year / 100k miles / 70%. However, I don't believe they have a working V2G or V2H solution in the US yet. They did do some demos in other countries (which may not even have capacity warranties or have the older ones), but I haven't seen a plug and play solution in the US yet.

Ford is offering it in the Lightnings which have a huge battery pack, so can take more abuse. They are not offering it in cars like the Mach E however, which is closer to the packs Tesla is using.

Hyundai's offering is the closest to what Tesla is offering, but Hyundai has always been very aggressive in their warranty offerings (to make up for other previous deficiencies in the brand).

 

[golfcart]

I get the whole powerwall argument for why Tesla wouldn't do it, but do any of y'all think that Tesla competitors offering vehicle to home battery backup with their EVs will finally push Elon to offer the same for Teslas? I'm not trying to live off the grid, I would just use it for emergencies like if a hurricane or nor'easter knocked out power for a few days. It just makes me mad to have solar panels plus an 80kWh battery pack sitting in my driveway and not being able to use it on those rare occasions.

 

[Gauss Guzzler]

No. V2G is one of those buzzword concepts only intended to impress politicians and investors. Like hydrogen, it appears to be the perfect and most obvious solution at first glance, only to become absurdly impractical upon closer inspection.

The charging cable you use at home can only handle 48A so you’d likely want to split your main breaker panel into two separate panels, with only critical items on the panel connected to the car.

You need to install an expensive switching system *between* your utility service and your main breaker panel(s). The car charger then has to be wired directly into that switching system - not to either main breaker panel.

The car needs additional hardware to be able to send synthesized AC power to the charge port. It already has an inverter easily capable of this, but that inverter is connected directly to the motor on a 1000A circuit. Switching that over to the charge port isn’t trivial.

Then the whole system has to be synchronized so that the AC phases are all aligned whenever power is switched.

And after all that, you’re still left with the conundrum of draining your car to save your house. So it ends up being a very expensive way to get a very small benefit for a tiny portion of the population in a very rare corner-case. Like hydrogen.

Also, no “competitors” are offering V2G. The few companies advertising it as an upcoming offering are only doing so to appeal to investors and politicians.

 

[golfcart]

No. V2G is one of those buzzword concepts only intended to impress politicians and investors. Like hydrogen, it appears to be the perfect and most obvious solution at first glance, only to become absurdly impractical upon closer inspection.

The charging cable you use at home can only handle 48A so you’d likely want to split your main breaker panel into two separate panels, with only critical items on the panel connected to the car.

You need to install an expensive switching system *between* your utility service and your main breaker panel(s). The car charger then has to be wired directly into that switching system - not to either main breaker panel.

The car needs additional hardware to be able to send synthesized AC power to the charge port. It already has an inverter easily capable of this, but that inverter is connected directly to the motor on a 1000A circuit. Switching that over to the charge port isn’t trivial.

Then the whole system has to be synchronized so that the AC phases are all aligned whenever power is switched.

And after all that, you’re still left with the conundrum of draining your car to save your house. So it ends up being a very expensive way to get a very small benefit for a tiny portion of the population in a very rare corner-case. Like hydrogen.

Also, no “competitors” are offering V2G. The few companies advertising it as an upcoming offering are only doing so to appeal to investors and politicians.

Interesting take. I already have some of what you said from my solar install and would only expect to keep the lights on and the fridge running but you make good points.

I priced out battery backup systems and thought they were way too expensive for a lot of the reasons you stated but assumed some sort of interface could be built by Tesla and hooked up to my breaker to make the car battery play nice with the house like a power wall does. Why is such an interface not possible in your opinion? Why would I be limited by a 48a cable couldn’t the interface have a beefier one? Or is the 48a limitation on the car side of things?

Ford claims to offer home backup power, are you claiming it is a lie?

https://www.ford.com/trucks/f150/f150-lightning/features/intelligent-backup-power/?intcmp=vhp-cta-backup-f-150-lightning

 

[jdcollins5]

No. V2G is one of those buzzword concepts only intended to impress politicians and investors. Like hydrogen, it appears to be the perfect and most obvious solution at first glance, only to become absurdly impractical upon closer inspection.

The charging cable you use at home can only handle 48A so you’d likely want to split your main breaker panel into two separate panels, with only critical items on the panel connected to the car.

You need to install an expensive switching system *between* your utility service and your main breaker panel(s). The car charger then has to be wired directly into that switching system - not to either main breaker panel.

The car needs additional hardware to be able to send synthesized AC power to the charge port. It already has an inverter easily capable of this, but that inverter is connected directly to the motor on a 1000A circuit. Switching that over to the charge port isn’t trivial.

Then the whole system has to be synchronized so that the AC phases are all aligned whenever power is switched.

And after all that, you’re still left with the conundrum of draining your car to save your house. So it ends up being a very expensive way to get a very small benefit for a tiny portion of the population in a very rare corner-case. Like hydrogen.

Also, no “competitors” are offering V2G. The few companies advertising it as an upcoming offering are only doing so to appeal to investors and politicians.

I understand what you are saying with the potential problem of the 48A limitation in the cable and charger.

There are plenty of us on here that understand the limitation and just want to run lights, refrigerators, etc. during power outages and know how to turn off all breakers in the panel except what we need. You can easily monitor the amp output at the car to make sure you keep it below the threshold.

 

[jjrandorin]

I get the whole powerwall argument for why Tesla wouldn't do it, but do any of y'all think that Tesla competitors offering vehicle to home battery backup with their EVs will finally push Elon to offer the same for Teslas?

Since you are asking for opinions, mine is still the same as it has been, in that IF tesla ever offers this at all, it would only be in context of an additional feature for people who already have their powerwalls, which means they already have the backup gateway, permits and all hardware except the car.

its my belief that tesla will never (ever ever ever) Offer vehicle to home or vehicle to grid as a stand alone feature, unless they go bankrupt and get bought by another company. You can hope for whatever, as long as you want to, but there is no reason at all for tesla to offer V2G when they are also the leading home battery supplier.

It wont happen, regardless of what other companies do. In fact, people who buy those other products will likely be shocked at what "official connection" will look like, from a cost perspective, because everyone is thinking they are going to roll up and plug their car in and be able to power their home without spending thousands and thousands on getting it setup.

They are in for a rude awakening when they see what it costs from other manufacturers to do that. Its less than a powerwall, but its still a lot more than people think. There is no reason for tesla to offer this to those that dont have powerwalls, and they wont ever do it, imo.

 

[golfcart]

Since you are asking for opinions, mine is still the same as it has been, in that IF tesla ever offers this at all, it would only be in context of an additional feature for people who already have their powerwalls, which means they already have the backup gateway, permits and all hardware except the car.

its my belief that tesla will never (ever ever ever) Offer vehicle to home or vehicle to grid as a stand alone feature, unless they go bankrupt and get bought by another company. You can hope for whatever, as long as you want to, but there is no reason at all for tesla to offer V2G when they are also the leading home battery supplier.

It wont happen, regardless of what other companies do. In fact, people who buy those other products will likely be shocked at what "official connection" will look like, from a cost perspective, because everyone is thinking they are going to roll up and plug their car in and be able to power their home without spending thousands and thousands on getting it setup.

They are in for a rude awakening when they see what it costs from other manufacturers to do that. Its less than a powerwall, but its still a lot more than people think. There is no reason for tesla to offer this to those that dont have powerwalls, and they wont ever do it, imo.

Fair points and yes I agree that the costs will be a surprise to many. When I priced out a powerwall or LG battery backup with my solar company it was not cheap even with the tax incentives. Honestly, a Generac home backup generator would do a better job for a lot less $$. I really just want to keep my fridge, internet, and lights on after a hurricane... it is too bad there isn't a cheaper solution for that given I have a huge battery in my car and panels on my roof. But like you said, maybe the incentives just aren't there for Tesla and the cost would make it prohibitive even if it was available.

 

[jjrandorin]

Interesting take. I already have some of what you said from my solar install and would only expect to keep the lights on and the fridge running but you make good points.

I priced out battery backup systems and thought they were way too expensive for a lot of the reasons you stated but assumed some sort of interface could be built by Tesla and hooked up to my breaker to make the car battery play nice with the house like a power wall does. Why is such an interface not possible in your opinion? Why would I be limited by a 48a cable couldn’t the interface have a beefier one? Or is the 48a limitation on the car side of things?

Ford claims to offer home backup power, are you claiming it is a lie?

https://www.ford.com/trucks/f150/f150-lightning/features/intelligent-backup-power/?intcmp=vhp-cta-backup-f-150-lightning

Piggy backing on what I said before, to get V2H for the ford that you linked, its going to be just under 4k US dollars, and thats only if you order the extended range battery version of the car. If you order the "standard range" battery version of the car, tack on another 1300, and thats also "costs may vary" so that means that is the MINIMUM charge.


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

Ford F-150 Lightning Home Integration System Priced At $3,895 - CleanTechnica

The Home Integration System that allows a Ford F-150 Lightning to serve as a backup power source has been priced.

cleantechnica.com

One of the most highly anticipated benefits of owning a Ford F-150 Lightning is the ability to use it to power a home during a blackout. But in order to use it for that purpose requires some planning and the installation of additional equipment in the home. You can’t simply park it, plug it in, and go inside to watch reruns of My Mother The Car in air conditioned comfort until the power is restored.

Ford has chosen Sunrun as its partner to install the Home Integration System needed to take advantage of the vehicle-to-home capability of the F-150 Lightning. Now it has announced what all this will cost — $3,895 to be precise, according to Matthew Stover, the director of charging and energy services at Ford. The Home Integration System consists of an inverter, a transfer switch, and a small battery to power the system temporarily when the main power goes out.

 

[golfcart]

Piggy backing on what I said before, to get V2H for the ford that you linked, its going to be just under 4k US dollars, and thats only if you order the extended range battery version of the car. If you order the "standard range" battery version of the car, tack on another 1300, and thats also "costs may vary" so that means that is the MINIMUM charge.


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

Ford F-150 Lightning Home Integration System Priced At $3,895 - CleanTechnica

The Home Integration System that allows a Ford F-150 Lightning to serve as a backup power source has been priced.

cleantechnica.com

One of the most highly anticipated benefits of owning a Ford F-150 Lightning is the ability to use it to power a home during a blackout. But in order to use it for that purpose requires some planning and the installation of additional equipment in the home. You can’t simply park it, plug it in, and go inside to watch reruns of My Mother The Car in air conditioned comfort until the power is restored.

Ford has chosen Sunrun as its partner to install the Home Integration System needed to take advantage of the vehicle-to-home capability of the F-150 Lightning. Now it has announced what all this will cost — $3,895 to be precise, according to Matthew Stover, the director of charging and energy services at Ford. The Home Integration System consists of an inverter, a transfer switch, and a small battery to power the system temporarily when the main power goes out.

Yeah but what’s a power wall cost? $12k? And it doesn’t do much of anything that the Ford system won’t do unless you buy 2 or 3 of them. I guess a Generac is probably better than either in a pure cost analysis if you want all your creature comforts but I still don’t see this as a terrible value.

 

[jjrandorin]

Yeah but what’s a power wall cost? $12k? And it doesn’t do much of anything that the Ford system won’t do unless you buy 2 or 3 of them. I guess a Generac is probably better than either in a pure cost analysis if you want all your creature comforts but I still don’t see this as a terrible value.

A generator is going to be much cheaper, if you want to just run your fridge and a few outlets. Whatever value or not you see in powerwalls is up to you. My point is, that people will say "but the competition is doing X" and either not know, or not mention, that for some of these new systems its "thousands" of dollars additional, with hardware etc.

 

[FlatSix911]

Yeah but what’s a power wall cost? $12k? And it doesn’t do much of anything that the Ford system won’t do unless you buy 2 or 3 of them. I guess a Generac is probably better than either in a pure cost analysis if you want all your creature comforts but I still don’t see this as a terrible value.

I agree - It seems like a relatively inexpensive solution to use the Ford V2G system compared to a Tesla Power Wall installation.

 

[stopcrazypp]

Yeah but what’s a power wall cost? $12k? And it doesn’t do much of anything that the Ford system won’t do unless you buy 2 or 3 of them. I guess a Generac is probably better than either in a pure cost analysis if you want all your creature comforts but I still don’t see this as a terrible value.

Yeah a power wall costs a whole lot more. That said, it's still $4k + labor, which is not nothing, and you need a car with a huge pack (Ford isn't doing this for cars like the Mach E for example). A backup generator is still going to be a way better option for the money for backup purposes and if you want have to a system for storing solar power, you would want stationary storage (not a car that likely won't be home during peak solar hours).

Hyundai also has a V2L solution in the Ioniq 5, which is basically just something that plugs into the J1772 port on the car and the other side is a 120V socket (OEM price is $550, there are ones shipping from Korea for $250). Not going to help power your house, but could be useful for camping or running a few accessories. I think something like that makes a lot more sense for general EVs.