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Tesla quietly adds bidirectional charging capability for game-changing new features - Electrek

Interesting speculation after reverse engineering of the inverter in the M3 reveals that it could work in both directions. This is very different to V2X using Chademo where the car returns DC to the charge point and the rectification takes place there, this would return AC to the charge point. There's no mention of phase control and load management but presumably that's all available.
 

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V2G is an interesting concept and it will be interesting to see how this develops. There are a number of electricity suppliers actively looking at this which makes sense when our EV's are sat parked up somewhere for a large part of the time.
 

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In the UK at least the time that there is most demand is 16:00-19:00. It is open to debate how many cars will be plugged in at this time with significant capacity that the owners are willing to release. For example I'm not normally back from work until 18:30 and have little remaining capacity at that point. Others may wish to keep their capacity to go out for the evening soon after the period. But there will be some who have the spare capacity.
 

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I think the grid bit is already done and going to be skipped more by most users in favour of V2H. Charge up while cheap overnight or at peak generation times(Octopus Agile price Plummets for eg) and then just release what he house needs the rest of the time.

This way there could be 2-3 charging periods in a day and the rest is slowly trickling out of the car battery.
 

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Lets Math Hammer this....
25'000 teslas
at least 75kWh.
Fully charged in the morning and average discharge.(35 miles..) leave about 64kWh.
assume average house uses 2kWh max in the TIME YOU ARE HOME.
you could take all those house "off the grid"

From a personal level
(if I had one off these fancy teslas)
I use 5kWh a day, assuming 3kWh is when the car is ther and 2 not

-0.05x (15 +3) = -0.90

0.15 x 2kWh to cover the rest off the day.= 0.30

Total= 1.10 a day.

thats £58 a month post tax i'd save.(or £85 off lease money)

that could potentally bring a tesla company car lease into my reach.

Nope still too expensive... need another 68pcm off money.
 

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...
assume average house uses 2kWh max in the TIME YOU ARE HOME.
you could take all those house "off the grid"
..
V2G can power other houses nearby and you can get paid for that.
You're restricting it to V2H.
 

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Discussion Starter #8
I think the grid bit is already done and going to be skipped more by most users in favour of V2H. Charge up while cheap overnight or at peak generation times(Octopus Agile price Plummets for eg) and then just release what he house needs the rest of the time.

This way there could be 2-3 charging periods in a day and the rest is slowly trickling out of the car battery.
Agreed. The exciting thing about the Tesla option is that it potentially overcomes the currently huge cost of the V2X unit.
 

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It's interesting, and disappointing, that Tesla are yet again going down a proprietary solution path. The failure isn't their own, CCS is way behind the curve on allowing V2X capability compared to Chademo, even if the cost of the latter is prohibitive.

The issue potentially with going AC Type 2 connection is that you're likely only going to see a few kW power available from the vehicle. That will mean that you will be able to cover base loads in most homes (lighting, refrigeration etc), but additional loads like heating (oven, kettle, heat pump) are going to need additional power from the Grid.
 

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Discussion Starter #10
The issue potentially with going AC Type 2 connection is that you're likely only going to see a few kW power available from the vehicle.
:unsure:
What do you define as "a few" in this context? The same as the charge point can supply to the car?

Most V2G Chademo solutions that I am aware of are limited to around 7kW in the UK so no different to the standard Tesla charge point in the UK. Obviously via 3 phase the rates could be considerably higher if your house has 3 phase and your DNO would allow it.
 

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Tesla quietly adds bidirectional charging capability for game-changing new features - Electrek

Interesting speculation after reverse engineering of the inverter in the M3 reveals that it could work in both directions. This is very different to V2X using Chademo where the car returns DC to the charge point and the rectification takes place there, this would return AC to the charge point. There's no mention of phase control and load management but presumably that's all available.
Synchronisation, Inverter certification, lots of issues not all technical.
 

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V2G can power other houses nearby and you can get paid for that.
You're restricting it to V2H.
In the short term. It won't last long term imo.

Having houses self power during the peaks is going to keep this going and eventually self sustainment when possible.
 

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It's interesting, and disappointing, that Tesla are yet again going down a proprietary solution path. The failure isn't their own, CCS is way behind the curve on allowing V2X capability compared to Chademo, even if the cost of the latter is prohibitive.

The issue potentially with going AC Type 2 connection is that you're likely only going to see a few kW power available from the vehicle. That will mean that you will be able to cover base loads in most homes (lighting, refrigeration etc), but additional loads like heating (oven, kettle, heat pump) are going to need additional power from the Grid.
7kw peak is a lot of juice for the average home! And it's more than enough to take another hit out of the grid.
 

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7kw peak is a lot of juice for the average home! And it's more than enough to take another hit out of the grid.
In a house with gas, yes. In a house without, not really. Especially when people are returning home and putting dinner on.

Oven can be 2kW, induction hob can be 2-3kW, then plus your heat pump running 2-4kW, it all adds up very quickly. Big consumers like electric showers will go beyond that.

Other comments on the limit from Chademo adapters, I'm surprised they are so low. I assumed you'd get at least 10kW from it (with an export limit set by DNO).
 

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Discussion Starter #16
In a house with gas, yes. In a house without, not really.
Good point. And the Government is aiming to stop new houses connecting to mains gas, so it will become more standard not to be. If only they would follow the mantra of Reduce, Reuse, Recycle themselves and reduce the consumption of heat significantly rather than shifting it to another source.
 

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Good point. And the Government is aiming to stop new houses connecting to mains gas, so it will become more standard not to be. If only they would follow the mantra of Reduce, Reuse, Recycle themselves and reduce the consumption of heat significantly rather than shifting it to another source.
We definitely should be doing that, but the current UK housing stock doesn't make that easy.
 

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In a house with gas, yes. In a house without, not really. Especially when people are returning home and putting dinner on.

Oven can be 2kW, induction hob can be 2-3kW, then plus your heat pump running 2-4kW, it all adds up very quickly. Big consumers like electric showers will go beyond that.

Other comments on the limit from Chademo adapters, I'm surprised they are so low. I assumed you'd get at least 10kW from it (with an export limit set by DNO).
Nope, chademo is capped at 7kw(really about 6.7-8) for V2x

And yes the case your describing would push past its limits, but it would do for a powerwall or two as well. The idea is to help take the big hit out of the grid so your not drawing down as much at peak times. And even better if you can export some as well.
 

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Nope, chademo is capped at 7kw(really about 6.7-8) for V2x

And yes the case your describing would push past its limits, but it would do for a powerwall or two as well. The idea is to help take the big hit out of the grid so your not drawing down as much at peak times. And even better if you can export some as well.
This is not correct.

Experience from our 300+ DC V2G installs:

The only technical limitation is the capacity of the cable and car.

Warranty however limits us to a daily usage and lower power level for cars we have already integrated our unit with. For example a Leaf is capped at 20kW max export power and 18kWh a day.

On the 'why not more than 6kW point' For domestic single phase it'd be largely wasted as most DNOs and cabling won't support it. The greatest export limit we have been granted on the trial is 9.6kW, for most participants its 3.6kW. Consider a battery and solar too and the extra capability from V2G is largely dormant.

AC V2G has some huge challenges unless you tie it to a specific EVSE that can manage the local installation and compliance part, for example G100/curtailment of other local renewables. No DNO is going to allow this to happen through any existing AC EVSE. Good to see and it could offer some significant cost savings over DC but still huge barriers to overcome.

My personal view is DC will win in the long run - we need the DC port for rapid charging anyway, The cost of an expensive onboard charger is better spent on home DC charging which gives the OEM opportunity to reduce their vehicle costs and weight.


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