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How much wattage to charge up an EV?

  • 01-10-2018 5:24pm
    #1
    Registered Users, Registered Users 2 Posts: 11,879 ✭✭✭✭


    take a Nissan Leaf for example - if you plug it into your home how many watts does it consume as its charging the batteries?

    also what happens if you have a long power outage (sometimes with some people lasting a couple of days) , say like in a storm, and you have to charge up your vehicle ? - how do you get by?


«1

Comments

  • Registered Users, Registered Users 2 Posts: 8,295 ✭✭✭n97 mini


    take a Nissan Leaf for example - if you plug it into your home how many watts does it consume as its charging the batteries?

    At home:
    Granny cable (aka 13-pin plug) = 2.2kw
    Home charge point = 3.3kw
    Home charge point, if supported by car and charge point = 6.6kw (some Leafs), 7.2kw for others like i3 and Ioniq.
    also what happens if you have a long power outage (sometimes with some people lasting a couple of days) , say like in a storm, and you have to charge up your vehicle ? - how do you get by?

    If you have no electricity you can't charge. You'd need to get a generator or drive to somewhere that has electricity.


  • Registered Users, Registered Users 2 Posts: 11,879 ✭✭✭✭Andy From Sligo


    n97 mini wrote: »
    At home:
    Granny cable (aka 13-pin plug) = 2.2kw
    Home charge point = 3.3kw
    Home charge point, if supported by car and charge point = 6.6kw (some Leafs), 7.2kw for others like i3 and Ioniq.



    If you have no electricity you can't charge. You'd need to get a generator or drive to somewhere that has electricity.

    thanks for that - thats quite high wattage .

    - and if your talking most home/small industrial petrol generators that would be pushing most of them to the limit wouldnt it?


  • Registered Users, Registered Users 2 Posts: 12,186 ✭✭✭✭KCross


    also what happens if you have a long power outage (sometimes with some people lasting a couple of days) , say like in a storm, and you have to charge up your vehicle ? - how do you get by?

    Go to a rapid charger on the public network..
    https://www.esb.ie/our-businesses/ecars/charge-point-map

    - and if your talking most home/small industrial petrol generators that would be pushing most of them to the limit wouldnt it?

    EV's can charge as low as 6A (1.3kW) so a small generator would handle that. Some EV's dont like small generators though if they are not properly earthed.


  • Registered Users, Registered Users 2 Posts: 22,635 ✭✭✭✭ELM327


    thanks for that - thats quite high wattage .

    - and if your talking most home/small industrial petrol generators that would be pushing most of them to the limit wouldnt it?
    I just googled domestic generator and while most were in the 2kva range this one is 6.7kva so should be perfectly capable of charging even a 32a Ioniq/i3


    https://ige.ie/neilsen-6-7kva-silent-diesel-generator-electric-start/?gclid=Cj0KCQjwrszdBRDWARIsAEEYhrdPiB1PAwinXn-F1zW2ccMQHVD7jgy4Ngpt_iweiBfCnivLU86JKqkaAkAgEALw_wcB


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    KCross wrote: »
    EV's can charge as low as 6A (1.3kW) so a small generator would handle that. Some EV's dont like small generators though if they are not properly earthed.

    Toying with the idea of picking up a cheap second hand petrol genny. You sometimes see a Parkside (Lidl) 1200W come up for around €50-€100. It looks like a very capable genny, from some research. I wonder how tight the 6A minimum is. 6A * 240v = 1440W, so well over the 1200W peak of the Parkside. Would it charge an EV at all? It has continuous output of 1000W, with peak of 1200W

    I'd get one just for having it. Probably never get to use it as in the 18 years in the house, we only ever had 1 powercut that lasted more than a couple of hours. And I could use the car to run an emergency electricity supply to the house. Probably never use it for charging the car either. But you never know.
    ELM327 wrote: »
    I just googled domestic generator and while most were in the 2kva range this one is 6.7kva so should be perfectly capable of charging even a 32a Ioniq/i3


    https://ige.ie/neilsen-6-7kva-silent-diesel-generator-electric-start/?gclid=Cj0KCQjwrszdBRDWARIsAEEYhrdPiB1PAwinXn-F1zW2ccMQHVD7jgy4Ngpt_iweiBfCnivLU86JKqkaAkAgEALw_wcB

    A massive diesel generator for massive money to charge your EV. Are you trolling ELM327? :p


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  • Registered Users, Registered Users 2 Posts: 22,635 ✭✭✭✭ELM327


    unkel wrote: »

    A massive diesel generator for massive money to charge your EV. Are you trolling ELM327? :p
    Not to charge the car solely but just to illustrate that such products exist.
    Plus charging it from a generator is not going to be very cost efficient I imagine.


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    KCross wrote: »
    EV's can charge as low as 6A (1.3kW) so a small generator would handle that. Some EV's dont like small generators though if they are not properly earthed.

    Toying with the idea of picking up a cheap second hand petrol genny. You sometimes see a Parkside (Lidl) 1200W come up for around €50-€100. It looks like a very capable genny, from some research. I wonder how tight the 6A minimum is. 6A * 240v = 1440W, so well over the 1200W peak of the Parkside. Would it charge an EV at all? It has continuous output of 1000W, with peak of 1200W

    I'd get one just for having it. Probably never get to use it as in the 18 years in the house, we only ever had 1 powercut that lasted more than a couple of hours. And I could use the car to run an emergency electricity supply to the house. Probably never use it for charging the car either. But you never know.
    ELM327 wrote: »
    I just googled domestic generator and while most were in the 2kva range this one is 6.7kva so should be perfectly capable of charging even a 32a Ioniq/i3


    https://ige.ie/neilsen-6-7kva-silent-diesel-generator-electric-start/?gclid=Cj0KCQjwrszdBRDWARIsAEEYhrdPiB1PAwinXn-F1zW2ccMQHVD7jgy4Ngpt_iweiBfCnivLU86JKqkaAkAgEALw_wcB

    A massive diesel generator for massive money to charge your EV. Are you trolling ELM327? :p


  • Registered Users, Registered Users 2 Posts: 12,186 ✭✭✭✭KCross


    unkel wrote: »
    Toying with the idea of picking up a cheap second hand petrol genny. You sometimes see a Parkside (Lidl) 1200W come up for around €50-€100. It looks like a very capable genny, from some research. I wonder how tight the 6A minimum is. 6A * 240v = 1440W, so well over the 1200W peak of the Parkside. Would it charge an EV at all? It has continuous output of 1000W, with peak of 1200W

    My bet is that it wouldnt relaibly charge the car, if at all.

    6A is the min and if it drops below that the car will stop the charge session... unless your Ioniq is different to the Leaf, which is possible.


    EV's also, I believe, check the earth and it might decide to reject the power from the generator regardless of whether it is delivering 6A or not. The Zoe is known to be very fussy on that front.

    I know on my own Leaf when I was bringing it back on the Ferry I asked them to give me access to a 3-pin socket and it refused to charge on it eventhough it did light up the granny cable... EV's need a good sine wave and good earth.... cheap genie's will probably fail both of those checks.


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    From research the Parkside has a good pure sine wave output and you can ground your genny easily enough. But I guess you're probably right, it's too light. No point in buying one that might not even perform one of the two tasks you'd buy it for in case you ever need them :p

    Still you could buy a 2-3kW one handily enough for about €150


  • Registered Users, Registered Users 2 Posts: 9,313 ✭✭✭Mycroft H


    unkel wrote: »
    From research the Parkside has a good pure sine wave output and you can ground your genny easily enough. But I guess you're probably right, it's too light. No point in buying one that might not even perform one of the two tasks you'd buy it for in case you ever need them :p

    Still you could buy a 2-3kW one handily enough for about €150




    Stretch your budget and get a Honda 2.2kW whisper generator. Rescue group I work with has one for outdoor lighting. It rarely gets used but it always starts first time even when lying up for a little while.


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  • Registered Users, Registered Users 2 Posts: 22,635 ✭✭✭✭ELM327


    If/when we ever move out the country again I will be looking at buying a generator to run the house during power outages. During the last 3 years living in a country house, we had many blackouts due to storms etc.

    I have ASD and suffer drastically with change in home situations and we also have a couple of reptiles and tortoises so they need constant heat too. For those reasons a generator can be an invaluable resource even if it's rarely used


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    For light backup use (tv, internet, charging phone, fridge / freezer), your EV will do nicely. I've yet to find out how much amps you can draw from the aux battery of Ioniq safely (with the engine on, of course, to keep it topped up)

    Obviously that won't do if you need to create heat. Pardon my ignorance, but does it do any harm for your pets to be cold for a day or so? I'd have thought being cold blooded, they could handle that?


  • Registered Users, Registered Users 2 Posts: 22,635 ✭✭✭✭ELM327


    unkel wrote: »
    For light backup use (tv, internet, charging phone, fridge / freezer), your EV will do nicely. I've yet to find out how much amps you can draw from the aux battery of Ioniq safely (with the engine on, of course, to keep it topped up)

    Obviously that won't do if you need to create heat. Pardon my ignorance, but does it do any harm for your pets to be cold for a day or so? I'd have thought being cold blooded, they could handle that?
    I havent found a way to do V2G/V2H from a non chademo car without invalidating the warranty. Even the Mirai has a chademo port for this reason.


    The tortoises particularly need constant heat and humidity, our climate will make them hibernate for most of the year. (There's about the most off topic post I think the EV forum will ever see :D:D)


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    ELM327 wrote: »
    I havent found a way to do V2G/V2H from a non chademo car without invalidating the warranty.

    Woot?

    How would the manufacturer ever know if you connected an inverter with crocodile clips to your aux battery? You can buy these things in any auto shop like Halfords.


  • Registered Users, Registered Users 2 Posts: 12,186 ✭✭✭✭KCross


    ELM327 wrote: »
    The tortoises particularly need constant heat and humidity, our climate will make them hibernate for most of the year. (There's about the most off topic post I think the EV forum will ever see :D:D)

    Wellll.... turtle mode in an EV is officially a tortoise if you look at the picture of it, so I think you can be afforded a little latitude on that one! :)


  • Registered Users, Registered Users 2 Posts: 12,186 ✭✭✭✭KCross


    unkel wrote: »
    Woot?

    How would the manufacturer ever know if you connected an inverter with crocodile clips to your aux battery? You can buy these things in any auto shop like Halfords.

    I dont think a few crocodile clips on the 12V battery could be considered V2G tech, its a little more complicated than that! :)

    ChaDeMo supports V2G today, CCS doesnt (yet). I believe thats what ELM is referring to.


  • Registered Users, Registered Users 2 Posts: 22,635 ✭✭✭✭ELM327


    unkel wrote: »
    Woot?

    How would the manufacturer ever know if you connected an inverter with crocodile clips to your aux battery? You can buy these things in any auto shop like Halfords.
    Exactly as kcross says, I don't think a few loose wires going to a 12v battery is quite the same as connecting the chademo connector on a leaf directly.


    I think CCS2.0 is rumoured to have V2G/V2H but I may have dreamt that.


    KCross wrote: »
    I dont think a few crocodile clips on the 12V battery could be considered V2G tech, its a little more complicated than that! :)

    ChaDeMo supports V2G today, CCS doesnt (yet). I believe thats what ELM is referring to.


  • Registered Users, Registered Users 2 Posts: 6,638 ✭✭✭zilog_jones


    What's the maximum power you could reasonably get from the 12V system anyway? Maybe 200-300W or so? It couldn't be considered a realistic V2H solution really.

    Both generations of the Prius PHV had an optional extra 100V AC 1500W inverter which gives you internal and external (via Type 1 adaptor) mains sockets - Japan only, of course. I think something similar is available in Japan for the Outlander PHEV - I've seen a kettle being plugged into it somehow. This stuff is a lot more marketable in such a disaster-prone country.


  • Registered Users, Registered Users 2 Posts: 22,635 ✭✭✭✭ELM327


    What's the maximum power you could reasonably get from the 12V system anyway? Maybe 200-300W or so? It couldn't be considered a realistic V2H solution really.

    Both generations of the Prius PHV had an optional extra 100V AC 1500W inverter which gives you internal and external (via Type 1 adaptor) mains sockets - Japan only, of course. I think something similar is available in Japan for the Outlander PHEV - I've seen a kettle being plugged into it somehow. This stuff is a lot more marketable in such a disaster-prone country.
    +1
    If you see the leaf 40 for comparison, Bjorn did a video where it was powering a coffee shop trailer via Chademo V2H.


  • Registered Users, Registered Users 2 Posts: 761 ✭✭✭Zenith74


    FWIW below is the electricity usage for our house over the last 10 months. Two BEVs were added in May/June to replace two petrol cars. I'd say we were spending about €200 a month on petrol, compared to about €50 per month extra on our electricity bill now.

    Electricity+Usage+with+two+BEVs.PNG


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  • Moderators, Sports Moderators Posts: 19,473 Mod ✭✭✭✭slave1


    unkel wrote: »
    For light backup use (tv, internet, charging phone, fridge / freezer), your EV will do nicely.

    Agreed, I had my eye on an inverter on Amazon for a while and when it hit the warehouse I snapped it up.
    Works perfectly via 5v socket or battery if higher load.

    Just hope I never have to use it now but it will keep my stove boiler pump and TV going as well as the wifi and fridge/freezer if leccie ever goes.
    Just going to park my ICE car and box the L30 in as you need to have the car on to use the 12v battery as your source...


  • Registered Users, Registered Users 2 Posts: 11,879 ✭✭✭✭Andy From Sligo


    how do you earth a genny by the way? - would you really have to like drive an earth rod into the ground?


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    KCross wrote: »
    I dont think a few crocodile clips on the 12V battery could be considered V2G tech

    I didn't mention V2H / V2G!

    We were just discussing emergency backup for your home essentials here. You can use either your ICE (with the engine running) or your EV (switched on) for this
    What's the maximum power you could reasonably get from the 12V system anyway? Maybe 200-300W or so?

    I'd like to think it's a lot more than that. But even with just 300W you can keep all the essentials I mentioned up and running. My own ancient inverter is that, just 300W

    Iirc both the Leaf and BMW i3 can handle 80A off the aux battery. That's nearly a kilowatt!!! I haven't seen figures for Ioniq. I also doubt you can get anything like that from an ICE as I suspect the alternator wouldn't be powerful enough to keep up with that.


  • Registered Users, Registered Users 2 Posts: 22,635 ✭✭✭✭ELM327


    unkel wrote: »
    I didn't mention V2H / V2G!

    We were just discussing emergency backup for your home essentials here. You can use either your ICE (with the engine running) or your EV (switched on) for this



    I'd like to think it's a lot more than that. But even with just 300W you can keep all the essentials I mentioned up and running. My own ancient inverter is that, just 300W

    Iirc both the Leaf and BMW i3 can handle 80A off the aux battery. That's nearly a kilowatt!!! I haven't seen figures for Ioniq. I also doubt you can get anything like that from an ICE as I suspect the alternator wouldn't be powerful enough to keep up with that.


    I wouldnt feel comfortable running the house on that sort of setup. I know what you're getting at now but to be honest it's too flimsy for me.


    I remember my leaf aux battery was only rated 60A (and it had the renault nissan badges still on it so it was the OEM supplied one). Havent even opened the hood of the Ioniq since I got it so I don't know what it's rated for. 20k km and not even looked under the hood.:cool:


  • Registered Users, Registered Users 2 Posts: 12,186 ✭✭✭✭KCross


    unkel wrote: »
    I didn't mention V2H / V2G!

    We were just discussing emergency backup for your home essentials here. You can use either your ICE (with the engine running) or your EV (switched on) for this

    Well, you replied and quoted a post from ELM specifically discussing V2G and invalidating warranty so that was the context provided.

    Maybe you missed that?


    Obviously a dealer/manufacturer wouldnt easily know you were running stuff off a few crocodile clips on the 12V although I'm sure they would figure it out if they looked at the cars logs which would show it running for hours on end with no mileage being clocked up and the DC-DC inverter kicking in to top up the 12V battery. That stuff is almost certainly all logged in the ECU.


  • Moderators, Sports Moderators Posts: 19,473 Mod ✭✭✭✭slave1


    KCross wrote: »
    ..That stuff is almost certainly all logged in the ECU.

    Interesting in these GDPR days would that data be available to them though without your permission, I highly doubt it


  • Registered Users, Registered Users 2 Posts: 12,186 ✭✭✭✭KCross


    slave1 wrote: »
    Interesting in these GDPR days would that data be available to them though without your permission, I highly doubt it

    Thats stretching GDPR a bit. All its doing is logging its own data. It doesnt have your name/address and bank details in its ECU! :)


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    KCross wrote: »
    Obviously a dealer/manufacturer wouldnt easily know you were running stuff off a few crocodile clips on the 12V although I'm sure they would figure it out if they looked at the cars logs which would show it running for hours on end with no mileage being clocked up and the DC-DC inverter kicking in to top up the 12V battery. That stuff is almost certainly all logged in the ECU.

    Even if it is logged at that level (which I doubt), you can just say you were charging up your heavy duty laptop through the cigarette lighter. There is no way they can disprove that (onus of proof is with them)
    ELM327 wrote: »
    I remember my leaf aux battery was only rated 60A

    60Ah, not 60A. Very different thing ;)


  • Registered Users, Registered Users 2 Posts: 1,707 ✭✭✭traco


    I don't know how good the EV charging circuitry is but I have seen a decent brand generator zap the charging circuitry for 72V lithium batteries. Do some research and make sure their out put is a nice and clean.


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  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    Was that some sort of test bench setup? I doubt it was an actual EV. Very unlikely the car will let you charge at all if it isn't happy with the output from the genny. And of course you will need a pure sine wave output.


  • Registered Users, Registered Users 2 Posts: 11,879 ✭✭✭✭Andy From Sligo


    would it be worth plugging into the generator socket a Surge protected plug/socket and then plugging the granny cable into that? - would the surge protector/spike protector smooth out the voltage enough for the granny cable electronics? - you used to be able to get RFI protected plugs/sockets at one time too.


  • Registered Users, Registered Users 2 Posts: 1,707 ✭✭✭traco


    unkel wrote: »
    Was that some sort of test bench setup? I doubt it was an actual EV. Very unlikely the car will let you charge at all if it isn't happy with the output from the genny. And of course you will need a pure sine wave output.


    Wasn't a bench set up - it was a guy with several Segways using them for events and topping up with a generator. I reckon the issue was due to a poor sine wave output or spike. Batteries were fine but the circuit on the charger got fried. The charger would have been suppling two 74V 5.2 A-hr Lithium battery backs.


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    Segway probably has a very rudimentary BMS compared to modern EVs I'd have thought. And anyway, if charging the battery of your EV with a genny causes damage, you should be covered under your 8 year battery warranty that pretty much all EVs have these days. The manufacturer can't tell if you used a genny or a home socket and the cable / BMS should only have worked on a good input.


  • Registered Users, Registered Users 2 Posts: 1,707 ✭✭✭traco


    unkel wrote: »
    Segway probably has a very rudimentary BMS compared to modern EVs I'd have thought. And anyway, if charging the battery of your EV with a genny causes damage, you should be covered under your 8 year battery warranty that pretty much all EVs have these days. The manufacturer can't tell if you used a genny or a home socket and the cable / BMS should only have worked on a good input.


    Not state of the art but not dumb, full cell balancing, analysis and conditioning etc. Not as high end as a car but not stupid either.



    The problem was the generator and the supply not being clean. Output from the charger would have been fine but the input side didn't like what hit it. That's what zapped the charger. Most cheap generators are for site work, power tools etc so their outputs can be crude.



    All I'm saying is I wouldn't trust a cheap generator on anything that may have high end electronics. I would trust an inverter generator but they are more expensive.


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    The one I mentioned (from Lidl) was about €149 brand new, it is an inverter generator and it produces a pure sine wave :)


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  • Registered Users, Registered Users 2 Posts: 6,638 ✭✭✭zilog_jones


    would it be worth plugging into the generator socket a Surge protected plug/socket and then plugging the granny cable into that? - would the surge protector/spike protector smooth out the voltage enough for the granny cable electronics?

    I think you're talking about a power conditioner (the problem with generators is not voltage), but even those might be designed for a source that's generating something resembling a sine wave.


  • Registered Users, Registered Users 2 Posts: 3,285 ✭✭✭cros13


    ELM327 wrote: »
    Exactly as kcross says, I don't think a few loose wires going to a 12v battery is quite the same as connecting the chademo connector on a leaf directly.


    I think CCS2.0 is rumoured to have V2G/V2H but I may have dreamt that.

    Yup, V2G is in the CCS 2.0 spec. I'm still very skeptical about V2G as a concept. There are so many advantages a dedicated home battery has over V2G and the costs are just not that dissimilar.
    traco wrote: »
    I don't know how good the EV charging circuitry is but I have seen a decent brand generator zap the charging circuitry for 72V lithium batteries. Do some research and make sure their out put is a nice and clean.

    Yeah, EV's onboard chargers are designed to gracefully handle pretty severe faults including surges, low/high current, DC power on AC pins, ground faults etc etc. Often there are additional onboard computers outside of the BMS (again there are layers of BMS and fusing on cell, module and pack level) and charger(s) itself which handle communications with DC rapid chargers and supervise the whole system.
    Remember we're often dealing with public charging infrastructure with dodgy power supplies and weather damage. I've charged at up to a hundred chargepoints and rapid chargers that triggered charging faults that were gracefully handled including both streetside and rapid chargers that turned out to be full of water.


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    cros13 wrote: »
    I'm still very skeptical about V2G as a concept. There are so many advantages a dedicated home battery has over V2G and the costs are just not that dissimilar.

    How so? We already have EVs, so the massive battery is free. A powerwall is less than half the size (less than a quarter of the size of the latest econobox EVs) and costs €7k or more

    It could of course be the case that the hardware to connect your EV to the grid (using CCS) will be expensive initiallly. But that doesn't take away from the concept of V2G. Why are you skeptical about the concept?

    I can see it being very common place in a decade or so, combined with a wireless connecting of the car to the home, so no plugging in required. Your EV should be able to reduce your electricity bill dramatically. Charging at very cheap peak solar mid day time and at windy night time and delivering electricity to the grid when it is expensive and demand is high (early evening)


  • Registered Users, Registered Users 2 Posts: 3,285 ✭✭✭cros13


    unkel wrote: »
    How so? We already have EVs, so the massive battery is free. A powerwall is less than half the size (less than a quarter of the size of the latest econobox EVs) and costs €7k or more

    Putting cycles on a more expensive pack using a chemistry that's not optimised for that use case. The car is also not always connected which in the case of time-shifting local generation is a problem, especially for solar since people are likely to be working/active during peak solar production hours.
    unkel wrote: »
    It could of course be the case that the hardware to connect your EV to the grid (using CCS) will be expensive initiallly. But that doesn't take away from the concept of V2G. Why are you skeptical about the concept?

    The average cost of currently available V2G inverters is about he same as the cost of a powerwall, B box or other home battery products.
    unkel wrote: »
    I can see it being very common place in a decade or so, combined with a wireless connecting of the car to the home, so no plugging in required. Your EV should be able to reduce your electricity bill dramatically. Charging at very cheap peak solar mid day time and at windy night time and delivering electricity to the grid when it is expensive and demand is high (early evening)

    I'm not entirely discounting V2H when everyone has a home battery anyway and we move to DC home charging. In that case shifting power between the two batteries is a use case that makes sense.


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    cros13 wrote: »
    Putting cycles on a more expensive pack using a chemistry that's not optimised for that use case.

    Meh. EV battery is under full warranty. Not my concern.
    cros13 wrote: »
    The car is also not always connected which in the case of time-shifting local generation is a problem, especially for solar since people are likely to be working/active during peak solar production hours.

    Cars are not used 95% of the time on average. Most of that is sitting at home. But yeah for the people at work during the day, I hereby introduce the acronym V2W (vehicle to work) :p
    cros13 wrote: »
    The average cost of currently available V2G inverters is about he same as the cost of a powerwall, B box or other home battery products.

    Sure, that was my point. All new tech is expensive. The battery pack in the first Leafs cost $25k for Nissan to buy for a car they sold for not much more than that :eek:

    This does not take away anything from the concept of V2G though. You stated you were skeptical about the concept


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  • Registered Users, Registered Users 2 Posts: 3,285 ✭✭✭cros13


    unkel wrote: »
    Meh. EV battery is under full warranty. Not my concern.

    Yes but cells still have a finite cycle life. At least in my case V2G would mean an average of 0.8 additional cycles per day for a 22kWh pack. That would cut my pack lifespan to 70% capacity (based on the data for my pack) from just over 9 years to 5.78 years. Why do that when I can buy a seperate pack with a 10-20 year warranty for pretty similar money to the V2G kit?

    And even if you are not doing high mileage... many people would want to keep the car longer than the warranty.
    unkel wrote: »
    Sure, that was my point. All new tech is expensive. The battery pack in the first Leafs cost $25k for Nissan to buy for a car they sold for not much more than that :eek:

    This does not take away anything from the concept of V2G though. You stated you were skeptical about the concept

    The issue is that I don't see a situation in which a smaller battery with a smaller inverter than a typical V2G, doesn't pretty much match a V2G inverter on price and match or beat it in practical terms for every scenario bar backup power.
    In addition to that, while currently V2G inverters are hand built, they are also mostly made from existing commodity components unlikely to see the reduction in unit cost battery cells will/are from economies of scale.

    The average household is likely to see the biggest impact from a home battery for the first 1kW of inverter capacity... a V2G kit because it's bidirectional has to have a large inverter to charge the car in an acceptable time.


  • Registered Users, Registered Users 2 Posts: 66,122 ✭✭✭✭unkel
    Chauffe, Marcel, chauffe!


    You're stretching there, cros :p
    cros13 wrote: »
    Yes but cells still have a finite cycle life. At least in my case V2G would mean an average of 0.8 additional cycles per day for a 22kWh pack. That would cut my pack lifespan to 70% capacity (based on the data for my pack) from just over 9 years to 5.78 years. Why do that when I can buy a seperate pack with a 10-20 year warranty for pretty similar money to the V2G kit?

    And even if you are not doing high mileage... many people would want to keep the car longer than the warranty.

    If it's as bad for the battery as you say, the battery will have been replaced under warranty before the 8 years are up. It really is not a concern for the user.

    cros13 wrote: »
    The issue is that I don't see a situation in which a smaller battery with a smaller inverter than a typical V2G, doesn't pretty much match a V2G inverter on price and match or beat it in practical terms for every scenario bar backup power.
    In addition to that, while currently V2G inverters are hand built, they are also mostly made from existing commodity components unlikely to see the reduction in unit cost battery cells will/are from economies of scale.

    Very speculative. No one knows what these parts / installs will costs when most kWh pricing is spot pricing for billions of people and millions of people have EVs connected to the grid in about 10 years time
    cros13 wrote: »
    The average household is likely to see the biggest impact from a home battery for the first 1kW of inverter capacity... a V2G kit because it's bidirectional has to have a large inverter to charge the car in an acceptable time.

    Of course. Deminishing returns. But a 7kW AC to DC converter (or should I say rectifier) as fitted to most EVs only costs hundreds now. Most likely the same will apply to a bidirectional 7kW rectifier / inverter in 10 years from now (or will we all have 3-phase or even DC charging at home by then?)


  • Registered Users, Registered Users 2 Posts: 22,635 ✭✭✭✭ELM327


    unkel wrote: »
    10 years from now (or will we all have 3-phase or even DC charging at home by then?)
    I've theorized that as batteries get larger and - assuming EV become the method of mass transport - that DC charging at home, at 10-20kW will become the main mode of home charging.
    Governments will be in favour of this as they will be able to monitor (and tax) these chargers a lot better than a dumb 16a/32a charger or a granny cable.


  • Registered Users, Registered Users 2 Posts: 12,186 ✭✭✭✭KCross


    We could have DC charging at home but it would be alot more expensive to install as you would then need rectifiers etc. If you think €1000 is too much for a dumb Rolec charge point, hold your wallet when you get quoted for a DC charger notwithstanding reduction in costs in 10yrs time!

    And if it were to come at 10kW+ it would require wholesale updates to the grid to support it, unless it was all tied into a smart grid system.

    Most transformers around the country can only take about 16kW and they are shared across multiple dwellings. Put four or five EV's DC charging at 10kW and watch the transformer glow!

    I cant see the grid being wholesale upgraded to support EV's unless you want a new levy added to your bill to pay for it.

    Similar thing for 3-phase. The infrastructure cost for that is enormous.... billions for sure.


  • Registered Users, Registered Users 2 Posts: 22,635 ✭✭✭✭ELM327


    KCross wrote: »
    We could have DC charging at home but it would be alot more expensive to install as you would then need rectifiers etc. If you think €1000 is too much for a dumb Rolec charge point, hold your wallet when you get quoted for a DC charger notwithstanding reduction in costs in 10yrs time!

    And if it were to come at 10kW+ it would require wholesale updates to the grid to support it, unless it was all tied into a smart grid system.

    Most transformers around the country can only take about 16kW and they are shared across multiple dwellings. Put four or five EV's DC charging at 10kW and watch the transformer glow!

    I cant see the grid being wholesale upgraded to support EV's unless you want a new levy added to your bill to pay for it.

    Similar thing for 3-phase. The infrastructure cost for that is enormous.... billions for sure.




    I paid more than €1k for my (non standard install) 32a domestic charger.
    That charges at 7kW.



    Charging at 10kW if you have the upgraded connection to (afair) 80a from 63a is not that much of a stretch. I'm not that au fait with how DC charging works at home, I assume same as higher power DC charging, you connect to the grid as AC and the charger converts (rectifys ?) the current to DC


  • Registered Users, Registered Users 2 Posts: 12,186 ✭✭✭✭KCross


    ELM327 wrote: »
    I paid more than €1k for my (non standard install) 32a domestic charger.
    That charges at 7kW.

    Charging at 10kW if you have the upgraded connection to (afair) 80a from 63a is not that much of a stretch. I'm not that au fait with how DC charging works at home, I assume same as higher power DC charging, you connect to the grid as AC and the charger converts (rectifys ?) the current to DC

    Yea, thats basically it.
    Its a small rapid charger basically without the fancy screen and RFID etc.

    A DC home charger will have more inside it than an AC charger therefore more expensive to buy.


    Its not so much going from 7 to 10 is the issue its having 10kW+ across mutliple dwellings who are sharing a transformer is the issue.

    So, your house and your car might be fine but aggregate that up across one transformer and you will see lights dipping across the neighbourhood. ESB would have to do alot of work to support that.


  • Registered Users, Registered Users 2 Posts: 3,285 ✭✭✭cros13


    I think you've got the wrong end of the stick there, KCross.
    I'm talking about the option of directly charging from the DC supply of the home battery / local Solar PV.
    No AC-DC involved so no recifiers and no loss at conversion. In that scenario treating both the home battery and vehicle battery as just pools of energy to be managed makes more sense.
    It's also very possible in the far future that we go to using DC directly in the home for most devices and appliances.


  • Registered Users, Registered Users 2 Posts: 6,638 ✭✭✭zilog_jones


    KCross wrote: »
    Most transformers around the country can only take about 16kW and they are shared across multiple dwellings. Put four or five EV's DC charging at 10kW and watch the transformer glow!

    Surely it's more than that? Two electric showers could be >16 kW.


  • Registered Users, Registered Users 2 Posts: 9,815 ✭✭✭antoinolachtnai


    Surely it's more than that? Two electric showers could be >16 kW.

    Well this is more of a rural setup than something you see in the city. In the city a much bigger transformer serves a larger number of houses. But some of the same issues arise.

    The electric showers only typically run for a few minutes or at most half an hour. Even if the transformer is temporarily overloaded it has time to cool down.

    It’s also a different type of load. The harmonics from rectifiers and charging will give rise to greater heat in the transformer.

    But there is, overall over 24 hours plenty capacity in the network, but it does need to be scheduled correctly.


  • Registered Users, Registered Users 2 Posts: 12,186 ✭✭✭✭KCross


    Surely it's more than that? Two electric showers could be >16 kW.

    Some are more.... take a look up the next time you pass one on the road, the markings are painted in big writing on it so you can read what its capable of.

    Usually 16kVA around the country.... housing estates etc would obviosuly be different as they would be fed by a bigger sub-station.

    The overall point still remains.... if in the distant future everyone was charging at 10kW+ it would be a huge drain on the infrastructure... and it would need to be upgraded to handle it. That would have to be paid for, by us the consumer.

    The ESB published a report on it and is available on the CRU website and that report was based on people having 3kW capable cars. The conclusions were that only small upgrades were required on an as needed basis. If you more than treble that power to 10kW+ then all bets are off.

    Ultimately, we dont need 10kW+ anyway. With 7kW today you can add more than enough per night for even a 2 car household so how would you justify upgrading the network to support 10kW+ when 7kW will do?


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