How much wattage to charge up an EV?

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.

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.

unkel

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.

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.

unkel

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

zilog_jones

Andy From Sligo wrote: »

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.

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.

unkel

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)

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.

unkel

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)

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

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.

unkel

You're stretching there, cros

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?)

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.

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.

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

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.

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.

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.

antoinolachtnai

zilog_jones wrote: »

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.

KCross

zilog_jones wrote: »

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?

ELM327

KCross wrote: »

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?

You can't charge 2*7kW cars overnight. Not without some load balancing or prioritisation because 14kW is too much and will blow the fuse.


And charging at 3kW is for the dogs, it's had its day but it's old hat. 3kW*8hours is only 24kWh gross. Cars now are coming with 40kWh+ batteries. Even my Ioniq at a measly 28kWh wouldnt charge to full overnight (8 hours night rate) on 3kW.


That's why I was suggesting 10kW. Realistically 10kW would be needed to charge a larger battery EV overnight. 10kW*8 is 80kWh so say 75kWh net to the car.If you split that between two cars you get 37kWh to each. Still better than charging for 8 hours at 3kW.

KCross

cros13 wrote: »

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.

Got ya, that option makes sense.
If only the poweralls would come down in price.

KCross

ELM327 wrote: »

You can't charge 2*7kW cars overnight. Not without some load balancing or prioritisation because 14kW is too much and will blow the fuse.


And charging at 3kW is for the dogs, it's had its day but it's old hat. 3kW*8hours is only 24kWh gross. Cars now are coming with 40kWh+ batteries. Even my Ioniq at a measly 28kWh wouldnt charge to full overnight (8 hours night rate) on 3kW.


That's why I was suggesting 10kW. Realistically 10kW would be needed to charge a larger battery EV overnight. 10kW*8 is 80kWh so say 75kWh net to the car.If you split that between two cars you get 37kWh to each. Still better than charging for 8 hours at 3kW.

I meant 7kW shared between the cars, not 7kW each.

Thats about 57kWh's to the batteries each night so about 450-500km's of range that you can add each night. How many people are going to need more than that in this country even with two EV's.... bear in mind thats every night.

You might have days where you need it and you can always start the charge session early if you have a particularly long run the next day... i.e. start it at 9pm instead of 11pm etc. The need for 10kW just isnt there in general.

unkel

No need for much doom thinking here, KCross. We have 20 years to up our grid gradually. And most EVs should charge at night where we already have overcapacity (and a lot of renewable electricity). At peak demand times we just need to make electricity very expensive to encourage a move to better times of electricity consumption.

KCross

unkel wrote: »

No need for much doom thinking here, KCross. We have 20 years to up our grid gradually. And most EVs should charge at night where we already have overcapacity (and a lot of renewable electricity). At peak demand times we just need to make electricity very expensive to encourage a move to better times of electricity consumption.

I think you might be confusing generation capacity on the grid and the delivery capabilty of that capacity to the home.

Shifting our usage to night time is a no brainer and smart grids, smart chargers, smart metering etc etc... all that is happening already but thats a different thing. Thats better utilising what we already have in relation to power generation.

Adding more renewables, capacity and shifting to night time usage doesnt automatically allow everyone to charge their cars at 10kw+. Upgrading the LV grid network and "every" transformer and cable feeding houses around the country is a big ask just to support faster charge speeds at your car. It would cost alot of money that you and me would have to pay for and I dont think those speeds are required for the masses... particularly in this country. If an individual wants it then they can request it and pay for it... as they can today.

unkel

Agreed. There's of course a reason we don't all have a 1000l petrol / diesel tank at our homes today to fill up our ICE car. Filling it up can be done cheaper at the local petrol station because of economies of scale and with a lot lower investment in hardware.

antoinolachtnai

For clarity, the domestic electricity distribution network is not designed to deliver anything like 7kW per house. It is designed to deliver around 2 to 3 kW/house, with all the houses drawing at once.

KCross

antoinolachtnai wrote: »

For clarity, the domestic electricity distribution network is not designed to deliver anything like 7kW per house. It is designed to deliver around 2 to 3 kW/house, with all the houses drawing at once.

Thats easier to understand, why didnt I just say that!

ELM327

antoinolachtnai wrote: »

For clarity, the domestic electricity distribution network is not designed to deliver anything like 7kW per house. It is designed to deliver around 2 to 3 kW/house, with all the houses drawing at once.

So at 7am while my car is possibly still charging and my neighbours have an electric shower - what happens?


Car drawing 7kW, electric shower probably 8kW, baseline domestic usage of approx 1kW per house too.

zilog_jones

Something to consider: How much electricity is consumed at the refinery in Whitegate, the various fuel distributors around the country, and at a typical petrol station? I've no point of reference but I can imagine the power consumption of a typical petrol pump is significant, considering the flow rate.

Of course this stuff won't disappear overnight, but their usage will be reduced as more people move to EVs, and this is energy being consumed in Ireland.