MASTER THREAD: Powering house or other things with Model 3

[stopcrazypp]

I think 120V outlets with 1500W capability are going to become much more common. Kia/Hyundai already support this as an option in their newest EVs.

Yes, Kia/Hyundai seems to be the exception in the US. The Leaf was said to have released an option that works via the CHAdeMO in Japan but it requires a box that is quite expensive (and not sure if they ever really released it in NA in any significant volume).

In Europe, I believe Honda e had a plug also in the car.

 

[FalconFour]

Not to flex, but this was my weekend, and what can _really_ be powered off a Tesla.

https://twitter.com/x/status/1566273200614281217

A bit around 1000w of lights, and around 500w (average) of sound... all night, sunset to sunrise.

12v cigarette-lighter port? lol lol. no

I can't emphasize this enough, because it's the first thing people tend to think to try: DO NOT connect to the 12v battery in the frunk. Do not, do not, do not. The right place is the PCS terminals under the rear seat (as done here). All my tricks are posted earlier in this thread, I think (would appreciate anyone digging them up if curious enough to search). Worked wonderfully, except for a brief moment where we tripped the 120v/15a safety circuit breaker I added. haha

 

[montreid]

Tesla wants to sell batteries -- aka Powerwall. Until there's enough pressure internally or external competition, Musk isn't going to change this.

I CAN see a future where an adaptor for Powerwall will become available to attach to Tesla EVs to daisy chain to support at least V2H/V2G/VPP

I don't buy the battery impact concern (at least from Tesla). Same battery in Powerwall and that's only 12kw size, deep cycles, and supports entire house without warranty impact.

 

[brkaus]

I don't buy the battery impact concern (at least from Tesla). Same battery in Powerwall and that's only 12kw size, deep cycles, and supports entire house without warranty impact.

Battery cell may look the same, but I was under the impression that the chemistry was different between the car & the power wall.

 

[montreid]

Battery cell may look the same, but I was under the impression that the chemistry was different between the car & the power wall.

Never verified and highly doubt Tesla would go to older tech and using higher cost materials.

EV cells perform quite well and under significantly more stressful environments then the PW.

In the case of daisy chaining an EV to PW, you're capping draw a 5KW per hour. That's sipping a straw for EV discharge. Plus you'll have to burn through 2 hours of PW before EV draw and SOC on EV even overnight 8 hours at 5kw will draw down <50% of an EV battery.

That's not significant drawdown for Tesla EV battery to see and handle easily, even repeatedly.

 

[Knightshade]

Never verified

repeatedly verified going all the way back to the original 18650 version of PW1

Tesla’s new “Powerwall” home battery will cost $3,500 for 10kWh units [Updated]

Elon Musk extols the virtues of battery power in an evening press conference.

arstechnica.com

Without going into specifics, he also noted that the battery is different in cell chemistry and design from the Model S. "I wish it was that easy," he said of the engineering transferability, adding that the automotive version of the lithium-ion battery pack "has a much higher ability to cycle."

 

[n2mb_racing]

Battery cell may look the same, but I was under the impression that the chemistry was different between the car & the power wall.

It would make a lot of sense to use LFP in the powerwall, rather than more expensive NCA chemistry. NCA in a powerwall wouldn't make any sense. There's no need for high power to weight and high capacity to weight.

 

[FalconFour]

older tech and using higher cost materials.

That's not the case in the battery world though. There is no "single best battery for every job". It's always a trade-off between energy density and performance -- how much energy you can cram into a single cell (of the same size/weight) varies depending on whether you want it to sustain "Spirited Driving" and Supercharging... or if you just want it to cram a ton of energy into the smallest(/cheapest) possible space, but charge and discharge it slowly and constantly.

As you might have guessed by this point in reading, that means Powerwall batteries can stand to be a fair bit different from vehicle batteries, to optimize for the application they're used in. You're not going to "floor your Powerwall" or Supercharge it any time soon.

There's a lot more that goes on inside a cell than just being "it's a lithium 18650". whatdaya think is inside, a tube of elemental lithium, or something... and magic makes it into a battery? Lots of knobs to turn, there.

That said, the battery we have in the cars is _already_ in the car, and the tuning for a Powerwall battery is done to make it more dense/smaller/cheaper tuned to the application of a Powerwall. The vehicle battery exceeds all those needs, and using it for stationary storage is probably way better for it than using it for driving - as far as stress/duty on the battery goes. Heck, cars would often benefit from it, not being left fully-charged all the time when people have a "come home, plug it in" routine every night...

For what it's worth, Kia/Hyundai/Genesis has a common platform between the EV6/Ioniq 5/GV60, that includes a bidirectional OBC -- that can export power without wild warranty-voiding hacks. That is to say, while Tesla will grumble and "void your warranty" for it, the Kia folks will sell you the freaking adapter to do it. Your move, Tesla!

 

[montreid]

The vehicle battery exceeds all those needs, and using it for stationary storage is probably way better for it than using it for driving - as far as stress/duty on the battery goes. Heck, cars would often benefit from it, not being left fully-charged all the time when people have a "come home, plug it in" routine every night...

For what it's worth, Kia/Hyundai/Genesis has a common platform between the EV6/Ioniq 5/GV60, that includes a bidirectional OBC -- that can export power without wild warranty-voiding hacks. That is to say, while Tesla will grumble and "void your warranty" for it, the Kia folks will sell you the freaking adapter to do it. Your move, Tesla!

This is my point. There's been this 'void your warranty' scare that EV batteries will suffer being leveraged to support V2G/V2H solutions -- it's quite the opposite where EV batteries will have a walk-in-the-park level stress compared to a regular daily commute usage.

It's a BUSINESS decision for Tesla -- sell more PW since you don't allow EV V2G solution. More $$$ to Tesla. Once the competition starts having sizable batteries AND volume adoption for V2G/H solutions -- Tesla will suddenly come up with their PW adapter to EV solution --- sell PW+more EVs in vertically integrated product.

 

[stopcrazypp]

This is my point. There's been this 'void your warranty' scare that EV batteries will suffer being leveraged to support V2G/V2H solutions -- it's quite the opposite where EV batteries will have a walk-in-the-park level stress compared to a regular daily commute usage.

V2G/V2H will be on top of the stress that EV batteries will see. It's not like if you use it for stationary storage, you will stop driving it. Instead you would put extra cycles on it. Tesla doesn't want to cover that usage, especially in chemistries where cycle life is not high (like NCA used in most Teslas today). NCA has on order 300-500 cycle life to 70% retained (Tesla have probably improved it a bit so I will assume 500 cycles for math following). Given a range around 200-300 miles at 500 full cycles, you get around 100k-150k miles which is what Tesla is warrantying for.
Tesla Now Has Multiple Battery Options: Which One Should You Choose?

The cells Tesla used for Powerwalls are NMC which has better cycle life (on order of 1000 cycles or more) at the cost of less energy density. Kia/Hyundai also uses NMC cells which give them more cycle life to allow for some accessory usage.
Tesla Powerwall – Lithium Ion Battery Test Centre

I don't see Tesla changing their policy until they switch fully to cells with higher cycle life (like the LFP cells).

It's a BUSINESS decision for Tesla -- sell more PW since you don't allow EV V2G solution. More $$$ to Tesla. Once the competition starts having sizable batteries AND volume adoption for V2G/H solutions -- Tesla will suddenly come up with their PW adapter to EV solution --- sell PW+more EVs in vertically integrated product.

See above, you guys are handwaving away the difference in the cell chemistries, when it actually matters.

 

[montreid]

V2G/V2H will be on top of the stress that EV batteries will see. It's not like if you use it for stationary storage, you will stop driving it. Instead you would put extra cycles on it. Tesla doesn't want to cover that usage, especially in chemistries where cycle life is not high (like NCA used in most Teslas today). NCA has on order 300-500 cycle life to 70% retained (Tesla have probably improved it a bit so I will assume 500 cycles for math following). Given a range around 200-300 miles at 500 full cycles, you get around 100k-150k miles which is what Tesla is warrantying for.
Tesla Now Has Multiple Battery Options: Which One Should You Choose?

The cells Tesla used for Powerwalls are NMC which has better cycle life (on order of 1000 cycles or more) at the cost of less energy density. Kia/Hyundai also uses NMC cells which give them more cycle life to allow for some accessory usage.
Tesla Powerwall – Lithium Ion Battery Test Centre

I don't see Tesla changing their policy until they switch fully to cells with higher cycle life (like the LFP cells).

See above, you guys are handwaving away the difference in the cell chemistries, when it actually matters.

Our 3 has 63k miles on it and 90% still at 4 years.
Our Y has 37k miles with still charging to original miles on it.

If one daisy chains onto an existing PW2 -- it limits 5kw discharge per hour. Even if one uses this for 3 hours after PW2 exhausted, 15kw is not a significant deep draw. My guess is that it'll sell more PW2 than any replacement warranty claims.

 

[n2mb_racing]

V2G/V2H will be on top of the stress that EV batteries will see. It's not like if you use it for stationary storage, you will stop driving it. Instead you would put extra cycles on it. Tesla doesn't want to cover that usage, especially in chemistries where cycle life is not high (like NCA used in most Teslas today). NCA has on order 300-500 cycle life to 70% retained (Tesla have probably improved it a bit so I will assume 500 cycles for math following). Given a range around 200-300 miles at 500 full cycles, you get around 100k-150k miles which is what Tesla is warrantying for.
Tesla Now Has Multiple Battery Options: Which One Should You Choose?

The cells Tesla used for Powerwalls are NMC which has better cycle life (on order of 1000 cycles or more) at the cost of less energy density. Kia/Hyundai also uses NMC cells which give them more cycle life to allow for some accessory usage.
Tesla Powerwall – Lithium Ion Battery Test Centre

I don't see Tesla changing their policy until they switch fully to cells with higher cycle life (like the LFP cells).

See above, you guys are handwaving away the difference in the cell chemistries, when it actually matters.

Agreed. Even if it wasn't a warranty issue, the battery is too expensive and has too few cycles to make any sense for use in v2g. The only case that makes sense is for emergency power.

Now, the LFP model 3/Y cars should be different and it could make sense to do v2g since that battery should far outlast the vehicle.

 

[montreid]

I would submit that most consumer purchase decisions come with options available; not warranty considerations at 7 years. From the company side decision it's also sales potential of one product vs another within own product line vs external competition.

To date, Tesla is had NO incentive to offer V2G when it can sell PW2 without any impedance. IF Tesla were truly green company tenants, it would have done this already. It's not. It's an energy company and interested in selling more batteries as fast and much as possible.

PW2 sales are robust and no reason to impact that negatively by offering V2g solutions -- UNLESS it helps sell more PW2.

When/if external competition ramps up sufficiently for V2G options; Tesla is not going to let the small warranty claims stop it from keeping PW2 sales up, and this daisy-chain extension allows both PW2 and EV sales synergized.

 

[stopcrazypp]

I would submit that most consumer purchase decisions come with options available; not warranty considerations at 7 years. From the company side decision it's also sales potential of one product vs another within own product line vs external competition.

To date, Tesla is had NO incentive to offer V2G when it can sell PW2 without any impedance. IF Tesla were truly green company tenants, it would have done this already. It's not. It's an energy company and interested in selling more batteries as fast and much as possible.

PW2 sales are robust and no reason to impact that negatively by offering V2g solutions -- UNLESS it helps sell more PW2.

When/if external competition ramps up sufficiently for V2G options; Tesla is not going to let the small warranty claims stop it from keeping PW2 sales up, and this daisy-chain extension allows both PW2 and EV sales synergized.

I'm not saying powerwall sales play zero role, but that there is still a significant cycle life difference between the cells (even though in some cases when you take care of your car's battery it does better, although the same applies to the powerwall). If battery cycle life gets so good that V2L or V2H or V2G doesn't matter at all, then the opportunity costs of offering the option becomes essentially zero, which changes the calculation for Tesla.

I think the first car with some V2L capabilities from Tesla will be the Cybertruck because that is expected capability in the truck industry and it will have a massive battery (so regardless of what chemistry it'll have more extra cycles available). If Tesla also moves more cars to LFP or a similar high cycle life chemistry they may also push it out. Currently it's a bit awkward how the lowest end cars have LFP, while the higher end ones do not, so offering it only on LFP cars will make it so lower end cars are more capable, which doesn't make sense for marketing.

 

[n2mb_racing]

I'm not saying powerwall sales play zero role, but that there is still a significant cycle life difference between the cells (even though in some cases when you take care of your car's battery it does better, although the same applies to the powerwall). If battery cycle life gets so good that V2L or V2H or V2G doesn't matter at all, then the opportunity costs of offering the option becomes essentially zero, which changes the calculation for Tesla.

I think the first car with some V2L capabilities from Tesla will be the Cybertruck because that is expected capability in the truck industry and it will have a massive battery (so regardless of what chemistry it'll have more extra cycles available). If Tesla also moves more cars to LFP or a similar high cycle life chemistry they may also push it out. Currently it's a bit awkward how the lowest end cars have LFP, while the higher end ones do not, so offering it only on LFP cars will make it so lower end cars are more capable, which doesn't make sense for marketing.

It makes sense, though. The high end cars for the foreseeable future won't have LFP, since they focus on energy density and power density, where NCA beats LFP.

I don't understand the economics of V2G. $25k battery with 1000 cycles = $25 / cycle. 100 kwhr battery means $0.25 per kwhr. Add in electricity at $0.10 per kwhr, means that someone has to pay me more than $0.35 per kwhr for V2G just to break even.

 

[miimura]

It makes sense, though. The high end cars for the foreseeable future won't have LFP, since they focus on energy density and power density, where NCA beats LFP.

I don't understand the economics of V2G. $25k battery with 1000 cycles = $25 / cycle. 100 kwhr battery means $0.25 per kwhr. Add in electricity at $0.10 per kwhr, means that someone has to pay me more than $0.35 per kwhr for V2G just to break even.

Your math doesn't make sense because the 1000 cycles is to some percentage capacity loss, say 70% capacity remaining after that many cycles. In an automobile you may not want to use the battery any more after that amount of degradation, but it still has useful life remaining. Also, if we are talking about using the battery for both driving and grid/home energy use, then you have to split that cost between the two uses.
For people that only use the power export for emergency power, the fraction of total use is small and the value of each kWh taken out of the battery is much higher.

 

[Jeff N]

If Tesla also moves more cars to LFP or a similar high cycle life chemistry they may also push it out.

According to a Munro & Associates teardown, Tesla’s new 4680 cells have an 811 NMC cathode.

 

[n2mb_racing]

Your math doesn't make sense because the 1000 cycles is to some percentage capacity loss, say 70% capacity remaining after that many cycles. In an automobile you may not want to use the battery any more after that amount of degradation, but it still has useful life remaining. Also, if we are talking about using the battery for both driving and grid/home energy use, then you have to split that cost between the two uses.
For people that only use the power export for emergency power, the fraction of total use is small and the value of each kWh taken out of the battery is much higher.

Sure, emergency use is totally different. I'd pay a lot per kwhr to keep my house running during a power outage.

But for routine V2G, I think basing the cost on 1000 cycles makes some sense. You won't want to keep the battery in your car after it degrades to <80% of the original. Maybe you could sell it for a second use, and so it has some value, so those earlier cycles aren't as expensive as we think. Also, if replacement cost in X years is a lot less than $25k, then today's cycles aren't that expensive either.

But, in any case, given that uncertainty, I'm not giving power back to the grid unless they pay me a lot per kwhr.

 

[stopcrazypp]

According to a Munro & Associates teardown, Tesla’s new 4680 cells have an 811 NMC cathode.

That would make sense, as Cybertruck will likely have power export capabilities, and 4680 was originally pointed out as mission critical for it. The chemistry with the large pack should give it a good margin.

 

[Dave EV]

According to a Munro & Associates teardown, Tesla’s new 4680 cells have an 811 NMC cathode.

Interesting article on the technical aspects of NMC 811 (benefits, drawbacks and challenges) for those interested:

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