Missed opportunity: No inverter

[cantdecide]

My wish list had something that was much more advanced than what others here wanted...
The car already has a way to convert 110v to batter voltage, and also 220V40Amp to batter voltage... the charger... can this be run in reverse?

What I wanted to see is a 14-50 220volt outlet (as well as 110volt outlet) on the back to plug a travel trailer into. Use cases:
1) towing a travel trailer... now I can run the trailer's refrigerator without needing to use propane [greenhouse gases etc]. Also when I get near my destination, turn on the AC in the trailer.
2) At an RV park with a 14-50 outlet... plug the car into the outlet, and the trailer into the car. Depending on AC etc trailer varies between 5amp and 40amp drawing... the car grabs the other 0-35amps to charge the car. By the end of the night the car is full and I've had all the power I want in the trailer.
3) Visiting a friend/relative for a reunion... park in the backyard, but they only have a 110volt outlet. Plug the trailer into the car and the car into the outlet. Now I get 220volt in the trailer to run everything, but average under 1000watts so the car net gains range also.
4) Friend comes over in a model S and we both want to charge overnight from a single 14-50... Daisy chain them instead of setting the alarm for 2am to switch them over. When we get our X we will have S,X,i3,leaf but only two 220volt charging capabilities.
The above is just somthing that makes full use of the car being electric, it is not something any gas SUV can do. Maybe next year's X will have it...

 

[Cosmacelf]

Awesome idea.

 

[Cyclone]

I can't help but picture think of Christmas trees from cantdecide's post. I concur that its a great idea, especially as having multiple Teslas in a household (or parking deck) grows.

 

[Hvt1958]

My wish list had something that was much more advanced than what others here wanted...
The car already has a way to convert 110v to batter voltage, and also 220V40Amp to batter voltage... the charger... can this be run in reverse?

What I wanted to see is a 14-50 220volt outlet (as well as 110volt outlet) on the back to plug a travel trailer into. Use cases:
1) towing a travel trailer... now I can run the trailer's refrigerator without needing to use propane [greenhouse gases etc]. Also when I get near my destination, turn on the AC in the trailer.
2) At an RV park with a 14-50 outlet... plug the car into the outlet, and the trailer into the car. Depending on AC etc trailer varies between 5amp and 40amp drawing... the car grabs the other 0-35amps to charge the car. By the end of the night the car is full and I've had all the power I want in the trailer.
3) Visiting a friend/relative for a reunion... park in the backyard, but they only have a 110volt outlet. Plug the trailer into the car and the car into the outlet. Now I get 220volt in the trailer to run everything, but average under 1000watts so the car net gains range also.
4) Friend comes over in a model S and we both want to charge overnight from a single 14-50... Daisy chain them instead of setting the alarm for 2am to switch them over. When we get our X we will have S,X,i3,leaf but only two 220volt charging capabilities.
The above is just somthing that makes full use of the car being electric, it is not something any gas SUV can do. Maybe next year's X will have it...

Personally I think there is more involved.
All talks here about outlets with supply capacity leads back to the fact Tesla decided the MS and MX not to store on behalf of the grid.

A larger source from the car might be used by people to stuff the can with all kind of heavy drains, think here electric mowers or chainsaws in remote destinations but also supplying back to the grid alike the powerwall will do.

In case the battery was made to supply to the grid Tesla would have dropped the warrantee on the pack long ago or would never have started a warrantee on the pack.
As a result Tesla must have blocked the use of larger power sources by just not putting it in and assured the contractors disengage at time we leave the car.

Batteries, (Lithium 10 fold of most other types) can only be drained and re-charged a certain amount of times.

 

[Nigel Tufnel]

I think your point is valid, Hvt, but don't you think Elon could come up with some way to allow low level short term AC draw without any significant negative impacts? I've heard that he and his crew are pretty smart.

 

[cantdecide]

It should be pretty easy to measure battery usage not by motor (I think the car effectively already does this) and put a warranty limit based on that which noone could achieve in normal usage. I.e. many people use 20kwh for driving the car per day... So set the warranty limit for external usage to be the equivalent of 10kwh per day... 3600 kwh per year.

 

[Jtrader]

I really think Tesla missed an opportunity to make the Model X insanely great in that they didn't include an inverter output. A lot of SUVs these days have 120 volt plugs at the back hooked to an inverter that can deliver several hundred watts. The problem with ICE cars is that to draw a lot of power from the inverter, you need to have the engine running or else you'll wear out your starter battery pretty quickly.

The Model X COULD have been a great tailgating car, or camping car with the addition of a reasonable power inverter built in. Drawing from the main battery pack, it would last a long time, no generator or car engine needed to be running.

Missed opportunity...

Tesla engineers probably don't tailgate very often because they're working all the time. That being said, would an inverter plugged into the 12v cigarette receptacle allow me to run an LED TV with the hatch open for 4 hours?

 

[ItsNotAboutTheMoney]

Tesla engineers probably don't tailgate very often because they're working all the time. That being said, would an inverter plugged into the 12v cigarette receptacle allow me to run an LED TV with the hatch open for 4 hours?

Limit is 150W. So, as long as the inverter is good enough and as long as the TV isn't too extreme, it should be OK.

 

[Cosmacelf]

The fundamental design problem is that we are forced to use the weak and underpowered 12v subsystem for inverters. Tesla should provide an option or accessory that is a much larger inverter that runs directly off the 400V main battery. Considering that Tesla now makes large 240v inverters for their Powerwalls, this isn't that much of a stretch.

 

[ORB]

Just to confirm for the Model S, the traction battery contactor opening with the car off means that the 12V battery will not be recharged in response to an auxiliary 12V load running with the car off (such as a small fridge connected via the 12V lead behind the nosecone), is this correct?

Thanks!

 

[scottm]

Just to confirm for the Model S, the traction battery contactor opening with the car off means that the 12V battery will not be recharged in response to an auxiliary 12V load running with the car off (such as a small fridge connected via the 12V lead behind the nosecone), is this correct?

Thanks!

Recharge of 12v happens automatically when voltage dips to a certain level after running your 12v loads for a while. On may car sitting idle in the garage, maybe 5 or 6 times a day, "smack" the contactors will close and a 12v juice up happens. If you're running heavy inverter loads off your 12v while parked you'll have many more cycles. Not a happy 12v battery.

You have no say in this. When the car senses the need, contacts close and the tractor pack juices the 12v up with a dc-dc converter/charger, and then releases when done. Note, this is entirely different from the on-board charger/s used to replenish the main pack from wall power.

FYI (and for completeness) the on-board chargers are not used when supercharging, they are bypassed. Whenever you're driving or charging the contactors are closed and the 12v battery is effectively charging all the time and staying at a constant voltage - so not cycling. A happy 12v battery.

Moral of the story: if you want to drive some heavy 120v inverter loads off 12v, do it while you're driving or charging.

 

[Screwbal]

Or throw it into camper mode where it's in neutral which should basically be a drive mode (not in park) and set the parking brake so it stays put.

 

[scottm]

Or throw it into camper mode where it's in neutral which should basically be a drive mode (not in park) and set the parking brake so it stays put.

Good point, any drive mode where the contactors have closed and the car remains on will do for not being a drag on the 12v cycling.

.. haven't found the camper mode button on my car yet but would like to see one anytime now would be nice instead of fooling the drivetrain.

 

[Screwbal]

^ there’s no real button for it though I’ve seen some 3rd party apps mentioned before that’ll do it for keeping you warm while sleeping. The term goes back to camping in the model S where there’s lots of space in the back once you fold the seats and could sleep. Problem with just turning on the heat and going to sleep is after 30 min or so it shuts off and you have to hit it again. Neutral + parking brake + door lock means you could/can lay in be back all night and have the climate on without fussing with it. Same thing should work I’d think for an inverter hooked to the 12v battery.

The woman (Nikki Gordon Bloomsfield I think is her name top of mind) who runs the Transport Evolved YouTube channel did a thing about it a while back with the Nissan Leaf (I imagine it carries over to our cars). The catch she pointed out was not to draw over 1kw continuous or you can exceed the rate the main battery feeds power to the 12v and you can actually drain th 12v even though it’s technically charging at the same time.

 

[ORB]

Thanks to you both for your info, the "hot standby" option with the parking brake is useful. Looks like the "car off" 12V current drain should be kept to a small percentage of the battery ampere-hour rating, and this kind of usage should be minimized.

 

[scottm]

... not to draw over 1kw continuous or you can exceed the rate the main battery feeds power to the 12v and you can actually drain th 12v even though it’s technically charging at the same time.

This is a very interesting nugget of information... thanks.

 

[Screwbal]

This is a very interesting nugget of information... thanks.

My number could be off there I’m going off her mention. I’m sure smarter people here can say for sure what the capability of the onboard charger is for throughput.