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Why is the inverter for a V2G so expensive £8000 to £9500 for a 10KW unit per Drive Electric in UK.
DriveElectric launches Vehicle to Grid charging service - DriveElectric



Is there not an inverter in an EV and why is this not available to connect the stored battery to the grid ?

Are there not 2 pin terminals available on the socket connection on an EV (CCS or Chadamo) available to connect the battery to an external inverter (which may be connected to a solar panel at the same voltage) ?
 

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The motive battery (DC) in an EV needs the external V2G inverter connected to the Chademo/CCS connector to make 240v 50Hz AC. They are so expensive because they are a low-volume manufactured product that required a lot of certification for connection to the grid and contain a lot of expensive protection and inversion kit.

The car has an on-board charger to charge the motive battery, it only works one way - taking mains AC power and charging the battery.

The other converter in the car takes high voltage DC from the motive battery and converts it to charge the 12v auxiliary battery.

You wouldn't want to connect solar panels directly to the motive battery. You should have dedicated DC solar charging equipment to do that.
 

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Is there not an inverter in an EV and why is this not available to connect the stored battery to the grid ?


Nothing that is immediately suitable. If the charger module in the car were designed to be bidirectional (rather than just AC->battery as it is at present), then it would be more expensive. There would also be significant safety complications in making the AC bidirectional, wheras the DC connection is inherently bidirectional.

Are there not 2 pin terminals available on the socket connection on an EV (CCS or Chadamo) available to connect the battery to an external inverter (which may be connected to a solar panel at the same voltage) ?
After suitable communication between the car and the controller in the chargepoint/V2G unit, yes the raw battery voltage appears on terminals of the socket, and you then need an inverter similar but not identical to a solar inverter of the same power to connect it to the grid.

So if you look at the price of a solar inverter, add a substantial extra cost for the CHAdeMO or CCS protocol controller, contactors and connector (the CHAdeMO connectors in particular are not cheap), you get the notional price of one of these units. Add then an allowance for the fact that these are currently only built in low volumes and you get the price you see now (actually, £8k-£9k is a pretty good price as things stand today).

Personally, I'm not at all convinced that full V2G is a good idea. You can get most of the benefit with very much smaller cost by simply managing EV charging speeds/times. In such a scheme, you would input by some mechanism the amount of charge you need and when, and the system would charge at time and rate to suit grid balance - maybe not charging at all some nights when you have enough for your commute the next day, maybe charging more than you need on other nights when there happens to be excess. This also side-steps issues of battery wear, and accounting for losses in the charge/discharge cycle (if you do real V2G, you are getting less out of the battery than you put in and need to account for that in the billing).
 

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Thanks for the replies.(and forgive any ignorance of the technical difficulty, bit of blue sky thinking)

So if you look at the price of a solar inverter, add a substantial extra cost for the CHAdeMO or CCS protocol controller, contactors and connector (the CHAdeMO connectors in particular are not cheap), you get the notional price of one of these units. Add then an allowance for the fact that these are currently only built in low volumes and you get the price you see now (actually, £8k-£9k is a pretty good price as things stand today).
Option 1.
If you have or more likely are going to invest in solar panels (of the correct output say 360v dc to match the leafs battery) you already have the sunk cost of a suitable inverter ?
Yes CHAdeMO connectors are pricey ($1000 to $2000) but surely in this application type the cost can be cut as only using DC cable/pins etc...can get plug for $120 here
ev charger plug Electric car Type2 IEC 62196 IEC standard CCS type 2 charging plug-in Chargers & Service Equipment from Automobiles & Motorcycles on Aliexpress.com | Alibaba Group

The cost of CCS/CHAdeMO protocol controller I can not get a fix on for such an application ??

The principle is the hybrid inverter system using solar and battery, but in this case direct use of the EV battery. e.g.
https://www.cleanenergyreviews.info/blog/2014/8/14/what-is-hybrid-solar

Alternatively there is the more complex option as set out in the following paper.
Vehicle-Solar-Grid Integration: Concept and Construction - IEEE Journals & Magazine



Option 2
In virtually all EV's the DC of the motive battery is inverted on board the vehicle to supply AC to the permeant magnet AC drive motor. (ignore and other inverter for the 12 V battery).
Could this inverter not be reconfigured to supply in Europe a 220/240V AC supply to either the AC motor or alternatively back to the grid.... and more so why not ?
I am guessing the AC is chopped for speed control but surely the electronics could be configured for either function. (reason to remove the need for a 2nd pricy external inverter).
Why not look to redesign the EV power electronics from scratch with this in mind ?


Why do this at all...i.e why V2G or V2X
The reason for the individual would be a combination of an additional revenue stream and possibly environmental considerations. (rebrand the car as the mobile power hub which travels with you and your energy needs. Similar to the smart phone which is much more than a phone.... )
Aggregation of the EV would enable revenue from ancillary services, capacity and trading (in a balancing market). From a study by National Grid UK V2G can earn £600 (US$980) per year for a 3 kW system to in the region of £8,000 (US$13,000) per year for a 50 kW three phase installation. This compares to Demand side management which would provide a modest annual financial return to the individual vehicle owner of approximately £50 (similar to the "managing EV charging speeds/times" that Arg alluded to).
Ricardo, National Grid study explores market potential for grid-balancing services for plug-in vehicles


From the grid perspective with the increase in renewables there is an imminent need for frequency support.
I live in Ireland which is a small grid approx. 7GW peak demand, currently 3.5GW of installed wind, with plans to increase this penetration to 6GW's. But this can only be done if the instability of wind/solar can be balanced. This is where batteries could step in, and why duplicate battery installation with wither industrial scale or "powerwall" solutions, when EV's can fulfill both the energy and transport needs.

Finally lets look at a utopian future where EV's represent 10% of road vehicles ?
In this scenario for Ireland that means 200,000 cars. Say 50% are grid connected V2G at any time at 10KW inverters?. That's 1GW of additional power over wind available to the grid (and generally more local to power demand).
Further push out to 50% of EV's this would mean more than 5GW's of power. This would eliminate the need for most thermal power plant !!!!

P.S. I do get the fact that as the number of V2G vehicles are connected the revenue to the individual would reduce proportionately but with mass roll out the cost of the technology would also drop and governments might be prepared to support V2G as replacement generation. Lastly as more V2G is installed the frequency and quantity of drawdown from each individual EV is less negating the concerns about battery degradation due to V2G cycling ????


Forgive me if I am a dreamer !!!
 

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Personally, I'm not at all convinced that full V2G is a good idea. You can get most of the benefit with very much smaller cost by simply managing EV charging speeds/times. In such a scheme, you would input by some mechanism the amount of charge you need and when, and the system would charge at time and rate to suit grid balance - maybe not charging at all some nights when you have enough for your commute the next day, maybe charging more than you need on other nights when there happens to be excess. This also side-steps issues of battery wear, and accounting for losses in the charge/discharge cycle (if you do real V2G, you are getting less out of the battery than you put in and need to account for that in the billing).
V2G is also there to cover spikes in demand, or problems when the grid has a failure. With extra demand from EVs, the grid will be extremely tight for capacity at times, and any failure would mean they have to fire up gas or diesel generators to cover the shortfall. The cost for having these backups on standby is significant. So a V2G architecture would mean that the extra load could be shared among ?millions of EVs and the expensive, dirty backups would become less necessary. Look at the Tesla Battery in Australia, where price spikes for backups drive up prices by 250 times How Tesla's big battery is bringing Australia’s gas cartel to heel
 
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