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GraemeQuote:
Originally Posted by GraemeCook
I agree and I can't really explain it either. I feel that it revolves around the hydroelectric production that is still the main source in Tassie. However, something does not fit there. I will try to see what is happening when I am next in at work, although I won't be able to see much more than your charts with the exception of the DC connector.
Regards
Paul
Of course it can be done but when thought about the whole V2H scenario has some real problems.Quote:
Originally Posted by Bushmiller
Is it cheaper to buy a car than a house battery?
Do I choose a car just because it has some form of V2H
Would a house hold battery and a cheaper car without V2H be a more flexible solution
You might say I remain unconvinced and you would be right. I see the advantages but there are a heap of conclusions being drawn by those who think it might be a good idea. A little less enthusiasm and a lot more facts would be a good idea.
ChrisQuote:
Originally Posted by Chris Parks
You make good points and it is very easy to get carried away with the glossy blurb, the spruiking and general hype. As always, the devil is in the detail and increasingly that is light on. Also we have to remember that individual situations can vary a great deal. This bi-directional charging is not going to be for everyone!
Regards
Paul
I agree that cars are only driven for a few % of the time and they are parked at home for most of their life.Quote:
Originally Posted by GraemeCook
However, what really matters is when an EV is parked at home during solar charging hours.
If someone goes to work at 7:30am and comes home at 5:30pm they will not get any significant EV-solar charging done so if the EV battery is used to power the home ON, by end of the week the EV battery could be flat.
Even a retiree like me, especially these days, often spends a fair bit of time away from the house during the day. Yesterday I went to a gardening centre in the morning and was away from 8:00am to 10am, Then at 11am I went to a hardware store, my sisters for lunch, to the physio, and then to fuel up the car car and got home at 4pm. All up I was driving for about 90 minutes (horrible city traffic) but was away from home for 7 hours during which time any EV would not have been charging. Last Saturday I drove to Fremantle to walk dogs with my brother, then the supermarket, and in the afternoon I went to a mates place, again about 90 minutes worth of driving but 6 hours away from home.
A smallish household battery would take care of all this and keeps things simple unfortunately it's unlikely to be economical for some time, but that is probably not going to stop me from eventually going this route.
If a 60kWh battery for Mr B's car is $15,000 to replace (so maybe an even smaller cost in the new car price) how much should a 3-5kWh battery for a home be? $5k or so, allowing for some different components being required? My only objection to having a house battery as well as a car battery is cost.Quote:
Originally Posted by BobL
Re cars not being available to be charged during the day: I think that "charge while you shop" is a great marketing opportunity, and would be a pretty good way to top up or add to the car charge (one could pre-book a charging time online). The local Woolworths/Big W building here is about 170 x 60 metres, which could take a helluva lot of solar panels. That doesn't help people who are out and about all over the place, but even a 15 minute charge would be a pretty big help.
Our whole energy situation will be unrecognisable in about 5 years time.
I've never seen this addressed: what happens to a home solar system if it gets hit by lightning? We live in a high-strike area.
Quote:
Originally Posted by Chris Parks
Chris, if you haven't looked at that page already, you may find it helpful. Not so much specs as an overview, but it spells out the fundamental differences.Quote:
Originally Posted by FenceFurniture
Yep a few $k is all they should be and hopefully that will happen in time.Quote:
Originally Posted by FenceFurniture
This works while EVs are just a few % of motor vehicles.Quote:
Re cars not being available to be charged during the day: I think that "charge while you shop" is a great marketing opportunity, and would be a pretty good way to top up or add to the car charge (one could pre-book a charging time online). The local Woolworths/Big W building here is about 170 x 60 metres, which could take a helluva lot of solar panels. That doesn't help people who are out and about all over the place, but even a 15 minute charge would be a pretty big help.
Solar panels for shopping centres makes a lot of sense to power the shopping centre itself but to power an EV in every parking spot is another level of power requirement.
Our big local shopping centre has 5000 Bays, even at just 5kWhr of charging per bay that is 25 MWhr of power, OK lets say only 1:10 are charging that is still 2.5MW, at 500 W/panel that's 5000 panels more than what the shopping centre itself will need.
I also doubt people would bother to hook up for anything less than a couple of hour for only 5kWhr charging. Might be different for 22kWhr or more but the the power/cost requirements will really blow things out of teh water.
FWIW I hate supermarkets and usually go early in the mornings eg 5-6am when there's few people around.
Yes, generally agreed Bob. I'm not suggesting that every parking spot is a charging spot though. Of course this whole landscape will change and develop over a decade and more, as tech changes and the % of EVs increases.
Brett, I understand what it is, perhaps more than most but you made the statement that V2L had less capacity than V2H and I wondered where you got the figures from. The prime vehicle quoted for this V2* is the Ford Lightening and there have been several well documented uses of it being used to power houses to a limited extent in the US.Quote:
Originally Posted by FenceFurniture
In the US it is common to have a whole of house generator usually gas powered and to facilitate its use there is automatic switching built into the installation just as described in the linked article so to plug in a V2H vehicle is not a big deal but try it here and very few houses have the needed equipment so the ability to automatically plug and forget is not easily done without that facility.
I don't know for sure why there is a low draw limit from the vehicle battery but I suspect it is because battery cooling is the issue. BEV's have quite complex battery cooling systems and if the vehicle is not being driven it might be difficult to cool the battery enough for a higher draw limit. 3600w drawn from the battery won't be 3600w delivered to the house due to losses in the delivery system and 3500w is two kettles heating water and not much else. The Atto starts at 3600w and drops to 2000w which is barely enough to heat one kettle.
If this V2H is to take off and my suspicion on cooling is on the mark raising the draw limit from the BEV will require an auxiliary plug in cooling system. The very high capacity chargers now entering the market for public use all have cooling systems built into the charging cables and it is this heating issue that is holding back even higher charging rates both in the charger and in the vehicle battery and is the same issue preventing higher loads being drawn from the vehicle in any V2* use if my assumption is correct.
I don't know how common LED lighting is these days but having it means there is a very low power draw in the house so that bodes well for using an auxiliary battery or even a house battery but some houses and mine is a prime example could not function on 3600w and I doubt I am Robinson Crusoe in that regard. Two freezers, lights, two fish ponds, appliances on standby, a large power hungry computer network, two smart TV's etc make for a large power draw. In the event of a blackout none of this stuff needs to be working but we are talking about driving a car into the car port in the evening and plugging it in to power the house at night every night and then you have to ask when is the BEV going to get charged because it is parked at work not plugged in to my solar system. Solar systems switch automatically from grid to panels and draw from both so yes the BEV will supply some power if the equipment is installed and the grid the remainder needed.
A lot of thinking is needed before the simple act of plugging in a car to a house and have no restrictions on use is the same as using a whole of house battery.
Chris, bear in mind that a large consumer of power might be told that V2H is not a total solution for them. I suspect that your power consumption is not typical (you are maybe 3x what we use), and perhaps you would need a house battery as well. I know you have detailed specs on your consumption, so maybe you can say what your maximum draw is in summer vs winter? I have just asked NCArcher what the typical maximum amperage feed is from the street to a house: "Older houses around 60A, newer are 80-100A location dependent". I guess that means that anyone who needs to draw anything above what the vehicle can put out will need to plug 2 vehicles into the system. :shrug: It's probably a fairly safe bet that any house drawing that much power probably has two vehicles, at least.
There's no universal panacea, and there will be a range of options needed (e.g. there are many many houses up here with no garage, and just the same in the inner cities)
Put this into Google: nissan leaf v2h specs
and it will tell you the output is 0-32A at peak power of 6kW (but that's only 200V)
Have a look at this site:
Bidirectional chargers explained - V2G vs V2H vs V2L — Clean Energy Reviews
It's an Aussie site, and they also have a forum, so you'll be able to ask all the questions there, I expect. They say they have no vested interest, don't sell solar equipment, and don't ask for a quote, but up the top it says "Get a quote", so I'm buggered if I know.
About 1/3 the way down it says that the new Ford F-150 has 4x 2.4kW outlets for V2L, so the batteries can obviously withstand a 9.6kW draw. I don't know how they arrange that, but perhaps they are drawing from four different sections of the vehicle's batteries.
The cooling of the car battery aspect had crossed my mind too. That is probably why V2H or V2G isn't as widely available yet because it would necessitate additional battery cooling being built into the car.
Scroll a little further down to Wallbox Quaser 2 which allows for 11.5kW at 48A (which is 240V) in either direction. Now the car battery has to also be capable of that, but they wouldn't be making a charger like that if it isn't possible now or in the very near future.
The other thing that might tell us what the battery can safely discharge is how much the car consumes. A Tesla S runs at 10kW at a speed of 110kph, which is obviously sustainable for a long time. The draw would be more (much more) under acceleration but that is only for short bursts so the battery isn't going to overheat. It's also at 350V, probably DC and a whole bunch of other things above my pay grade.
I don't know if battery heating is different for charging vs discharging, but if it can stand 7.4kW charge on single phase or 11kW charge on 3 phase (Volvo XC40 specs) then you'd have to think they could probably discharge at the same rate.
Anyway, a Tesla Powerwall can only discharge at 3.5kW as near as I can tell, so that's way under what vehicles can do. In other words, large sparks consumers would probably need 2-3 Powerwalls at $14k a pop....
Tesla BEV batteries need pre-heating before heavy discharge is possible as well as pre-heating before maximum charge rates are possible. I haven't read all the links and most probably won't as all the stuff I have read up to now here and elsewhere is speculation at best, 10 years ago Tesla was just firing up the world to the possibility of converting to BEV and just yesterday Tesla declared lithium batteries dead so any crystal balling into the future is just that, crystal balling. The V2* car fleet capable of all this speculation is decades away because lead times in the automotive industry takes at least 5 years and about that again to sell enough vehicles to make it a financial success.Quote:
Originally Posted by FenceFurniture
I have not seen anyone admit the reality of how long it will take to achieve a car fleet big enough to have any measurable effect on saving energy in a house and that depends on charging the battery from green sources. Everyone needs to get real, take a deep breath and actually think about all this V2* stuff and while that is done I am outa here.
About the same, if measured in kilowatt hours capacity.Quote:
Originally Posted by Chris Parks
Effectively, the car is the free box in which the batteries are delivered.
Or the house batteries are in the plastic box masquerading as a gold box...Quote:
Originally Posted by GraemeCook