Improving functionality

[malcolm]

V2v

Damn! Almost forgot.

It would be really useful if you can recharge Tesla cars by connecting two together via the (updated?) mobile charger- so called Vehicle To Vehicle or V2V.

Obviously this is only going to be available initially for those lucky enough to purchase two Teslas, and as the numbers of EVs grow then presumably we'll have to go through the EV equivalent of the BluRay/HD format war. But then, that's going to happen with any centralised battery-swap or commercial fast recharge stations anyway.

Still it would be a useful feature if Model S and the Roadster can recharge each other in an emergency.

 

[Chris H.]

Malcolm,

that's a really good idea, and, to be honest, it's one that had not occurred to me before. I suppose it would also be a good idea for tow trucks to carry some kind of charger and ESS as EVs become more common on the roads.

All the best,

Chris H.

 

[malcolm]

Yeah and it makes a good case for selling more Tesla EVs rather than waiting for some brave/foolhardy soul to bite the supermarket recharge station or battery swap outlet bullet.

What happens if I run out of charge? Phone your partner to drive your other Tesla out to rescue you. Or maybe it could be an aspect of the Owners Club - assuming members live fairly close to each other.

 

[Brent]

Yeah and it makes a good case for selling more Tesla EVs rather than waiting for some brave/foolhardy soul to bite the supermarket recharge station or battery swap outlet bullet.

What happens if I run out of charge? Phone your partner to drive your other Tesla out to rescue you. Or maybe it could be an aspect of the Owners Club - assuming members live fairly close to each other.

It's a great idea to have the option, although I might opt for roadside service if it had something similar. Why bother my friends when I can bother the car company?

 

[TEG]

What happens if I run out of charge?

Someone can tow over a generator if you don't want to have the car towed to a charging station.

 

[vfx]

"It would be really useful if you can recharge Tesla cars by connecting two together via the (updated?) mobile charger- so called Vehicle To Vehicle or V2V."

Neat idea but wouldn't you end up with two cars with an equal amount of energy?

It seems the max "fill up" would be half of what the charging vehicle battery has to offer.

 

[doug]

"It would be really useful if you can recharge Tesla cars by connecting two together via the (updated?) mobile charger- so called Vehicle To Vehicle or V2V."

Neat idea but wouldn't you end up with two cars with an equal amount of energy?

It seems the max "fill up" would be half of what the charging vehicle battery has to offer.

With some electronics in between (e.g. a transformer), you can "fill" one while "emptying" the other.

 

[TEG]

It would be really useful if you can recharge Tesla cars by connecting two together via the (updated?) mobile charger- so called Vehicle To Vehicle or V2V.

Blast from the past

# Malcolm Wilson wrote on February 6th, 2008 at 8:34 am
## Also can any single Tesla be used as an emergency mobile charger for another Tesla? Is V2V allowed.
TEG wrote on February 6th, 2008 at 9:31 am
Good point! I was always thinking of someone towing a generator out to the stranded vehicle, but if you could share your power that would be even better.
The Tesla emergency roadside service vehicle could be another Tesla!
On the surface, it would seem like this would be technically feasible.
ICE vehicles give each other “jump starts” all the time with you offering “jumper cables” to hook your battery to someone in need.
Why not do that with the traction pack as well?

 

[vfx]

With some electronics in between (e.g. a transformer), you can "fill" one while "emptying" the other.

Transformer = heavy

 

[malcolm]

Blast from the past

Damn. My secret's out! I don't have anything new to say, I just recycle the same comments every six months or so. :biggrin:

Yes vfx is quite right, two cars can only share a bit of charge (say 20% max?). But with moderate driving at 50 mph the Roadster can go ~40 miles on 10kWh.

This is really only suitable for a recovery situation. Towing around a portable ICE-driven generator is obviously a better way to deliver more charge - either in an emergency or for a really long journey where you need to cover several hundred miles in a day (Elon's 1% of journeys).

I just like the simplicity of Tesla not needing to invest in helping develop a battery swap system or commercial recharging stations. Their focus is the cars - so the best mobile recharger is (for their business) another car.

Tesla really shouldn't get involved with charging/swapping infrastructure stuff. Stick with the cars guys.

 

[vfx]

"Tesla really shouldn't get involved with charging/swapping infrastructure stuff. Stick with the cars guys."

No, Tesla should be heading up the international standards for charging. We don't need competing incompatible charge stations again.

I'd say Tesla should partner with Shai at Project Better Place. Once there are thousands and thousands and tens of thousands of chargers in India, Denmark. Hawaii and San Francisco, the chargers will become the defacto standard.

 

[WarpedOne]

No, Tesla should be heading up the international standards for charging. We don't need competing incompatible charge stations again.

The reality is no new charging standards are really needed. We have our home 120/240V outlets. We only need to get the idea that we need quick charging out of our heads. We don't.

Developement of such a standard and implementation of widely spread quick charging grid does not warrant the costs involved. How many people will use it and pay much higher price when they can charge at home over night?

Indeed, developing such quick charging grid could mean some car maker will stop offering homecharging capability. And we do not want that to happen.

 

[vfx]

Well already the AC plugs worldwide are all different. It would be nice if the EV makers got their act together before they put out product.

I agree that the cars should plug in to standard plugs via adapters but remember that Tesla's charger has a lot of "smart" features with the power source talking to the car and Vice Versa. These safety measures are what I am talking about as much as the form of the plug/socket.

 

[vfx]

By the way, the idea of a Tesla on the side of the road with a dead battery and another Tesla driving up and plugging in for a few minutes to charge the dead one is cool.

Makes me want to by two!

 

[WarpedOne]

.. in for a few minutes to charge the dead one is cool.

Few minutes like 10 minutes? At 17kW that is 2,8kWh which is about 5% of maximum charge or about 10 miles of aditional range.

It sounds cool just as rocket belts sounds cool also. But both just do not work in practice.

 

[malcolm]

Makes me want to by two!

Exactly! :biggrin:

And yes "a few minutes" may be a bit optimistic, unless two Teslas connected can offer the (pointless?) Holy Grail of EV recharging - Ultra Fast. Make it a unique feature only available when two cars are connected. Additional selling point.

Battery cooling energy consumption will probably prohibit this, however. A bit embarassing if 10kWh delivery requires a further 20 kWh to stop both battery packs melting.

 

[malcolm]

Damnit!

The more I look at this, the uglier it gets.

Suppose we want to deliver 10kWh of energy to the exhausted car (for ~40 miles driving). Taking one hour at 240 V means 42 Amps. But we know 70 amps requires 17kWh for cooling, so the exhausted car will require a further 42.5 Amps for cooling.

So apart from needing a new cable rated for 100 amps, the suppling car will need to give up 20.3kWh to the other car AND consume a further 20.5kWh of energy keeping its own battery cool.

So donating 10kWh in an hour to one car requires the sacrifice of 41kWh from the other.

Great. I have almost successfully stranded two cars instead of one!

Looks like V2V is a non-starter with present battery pack technology unless you are prepared to put up with recharge times of several hours! Not quite the emergency rescue I had in mind.

 

[vfx]

It sounds cool just as rocket belts sounds cool also. But both just do not work in practice.

Why? Is something wrong with your rocket belt? Mine works fine!

 

[Chris H.]

Perhaps the towable generator is the best option for a stranded car too... A service vehicle brings the t.g. to the stranded car, hooks it up, the tech says "Awlright guv'nor, give her 30 minits, an it's good, innit?"

Know wot I mean? :smile:

Chris H.

 

[malcolm]

I agree, but this need for battery cooling makes 30 minutes very tough for a reasonably sized generator. People expect Emergency recovery time scales to be far lower than typical recharge durations. That's the problem here.