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Discussion Starter #1
Hi,
I've become aware of vehicle to grid technology. It seems very interesting and appears to require specific charging technology (not a surprise).

However, does this mean that my current zappi charger will be obsoleted by this - I've heard about poc trials in London?

Thx
D
 

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No current (or indeed any future) AC EVSE will be able to do V2G unless there are some fairly radical changes to the technology built into the cars themselves. V2G only woks through a DC connection, and currently only CHAdeMO can do it. The Zappi has no possible way of doing V2G.
 

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Discussion Starter #5
Interesting. So would I be right to think that chargers like the Zappy are obsolete, or will be in the none too distant future? So we'll all be paying out twice for home charging in order to benefit from v2g?

Thx
D
 

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I shouldn't worry, I think it's quite likely that your Zappi charger will be wearing out before V2G becomes economic. The V2G chargers are still very expensive because they are far more complex than an AC charger, they're mostly being installed as part of government funded technology trials because the current cost makes them uneconomic.

I think it's unfortunate that they've got so much attention and funding, while smart charging which provides much of the benefits for a fraction of the cost is rather neglected.
 

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I think V2G would work for owners that don't have a daily use of their car and can afford to have the car's battery being used for that purpose.
I'm still to be convinced that the additional cycles don't affect the battery's life regardless manufacturers added warranty.
This is uncharted territory and nobody knows what long term effect this have on the batteries.
 

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Discussion Starter #8 (Edited)
I think it's unfortunate that they've got so much attention and funding, while smart charging which provides much of the benefits for a fraction of the cost is rather neglected.
The attraction to me is that I could use my car as a second home battery. But I won't have a home battery until the tech improves and the market become more competitive. Can you elaborate on how smart charging provides much of the benefit at a fraction of the cost?
 

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Discussion Starter #9
I'm still to be convinced that the additional cycles don't affect the battery's life regardless manufacturers added warranty.
This is uncharted territory and nobody knows what long term effect this have on the batteries.
Right now this may be true. But I expect the next generation of batteries will be well capable of handling the gentle roll-on and roll-off of charge to/from the grid/house.
 

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The attraction to me is that I could use my car as a second home battery. But I won't have a home battery until the tech improves and the market become more competitive. Can you elaborate on how smart charging provides much of the benefit at a fraction of the cost?
By using V2G you change your load to use electricity at its cheapest cost, i.e. you power your house from your car and as a bonus can sell some electricity to the grid to get a financial benefit.

Smart charging also changes your load for financial benefit by charging the car when electricity is at its cheapest. Obviously you cant power the house from the car or sell electricity back to the grid but you don't have the equipment cost.

Cheers.
 

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While Zappi or openEVSE are great in this regard, it is only one way: charging. So benefit is also only one way: charging your car. You can't offset your dinner oven cooking with energy you have cheaply stored in your car.

Let's consider this, my home uses 10 kWh normally. Let's say during peak evening I use 3-4 kWh. That means if I were to set V2G (or rather, V2H) to discharge the car during that peak evening period, I would only use about 15 miles of range. If I arrive home with 30% remaining on a 50kWh car, use it down to 22% over evening is still not too low.

Would increased use accelerate battery degradation? From data we currently have, it seems age of battery plays a bigger role in degradation while gentle slow charging and discharging does not put a lot of stress on the battery. We see 100k taxi Leaf with all health bars while older average mileage Leaf loosing health bars. A hosuehold peak rate of 7kW, <1kW typical will be a lot kinder than 20kW constant drain when driving on motorway.

In summary, I'd happily put cycles on my battery, especially our local runabout, in exchange for cheap tariff. Considering age of the battery will reduce its range at a steady rate.
TLDR: battery health is use it or loose it, might as well use it to pay <5p per kWh rather than 30p per kWh.


Home battery are a nice idea, and it's more mature tech than V2G. But I honestly don't see any point in this at early stage where we have a shortage of battery production. When we are home and using electricity, our cars are most likely also home. You'd never run your car down to almost 0% risking getting stranded, so there's pretty much always energy left in the car ready to off-set your peak time usage.
 

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With smart meters and electricity costs varying with demand + the added complication of vehicle to grid, how will you ever know if one provider is cheaper than another. Switching sites already have made it difficult for E7 users.
 

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The home charging points will need to be upgraded right enough - they will need to have an inverter, just as PV setups do and for the same reason.

On the life of batteries - this seems to be a developing area. There are studies out there which seem to show the potential for degredation, AND others that show the potential for enhancing the life. More interestingly, two of these teams have got together and seem to agree that both those things are a possibility, depending on regime.

But V2G and V2H are both moving in the direction of microgrids, which the CEO of National Grid seems to reckon is where the future lies.

CCS doesn't currently support DC-out, only in. Though apparently a standard for this is scheduled for agreement by 2025. So I was intrigued by the link above indicating that the Honda E will offer this. Not sure if that means it will be an upgradable option once the standard comes along, but I would assume the option for this is foreseen.
 

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No current (or indeed any future) AC EVSE will be able to do V2G unless there are some fairly radical changes to the technology built into the cars themselves. V2G only woks through a DC connection, and currently only CHAdeMO can do it. The Zappi has no possible way of doing V2G.
Wocs are for cooking food.
 

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With smart meters and electricity costs varying with demand + the added complication of vehicle to grid, how will you ever know if one provider is cheaper than another. Switching sites already have made it difficult for E7 users.
Data is key.

Smart meters and/or supplier portal should allow export of your half-hourly consumption data in a standard format. You can then upload this consumption over a year against another smart tariff to get an idea of your pricing.

I am using EmonCMS from OpenEnergyMonitor to fit my consumption (measured using slightly less accurate CT clamps) against Octopus Agile, I can see I would average around 8p/kWh over last 2 months if I were on their tariff. The more I drive in EV, the more I can pull down this average.
EmonCMS also has demand shapper module, where it can take tariff data from smart suppliers and turn on controllable stuff during lowest price slots (eg. OpenEVSE)
 

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Discussion Starter #20
I don't think this is going to be a case of either or. They're on convergent paths. V2G features seems to be a superset of smart charging so smart charging will be superseded. This is a strong argument for buying the cheapest charger possible now, knowing you're going be stung again anyway in the future. End users having to be careful of being milked, especially given the kind of relationship the government maintains towards consumers vs the utility companies...
 
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