re: Mileage results & random EV musings

If the local BMW dealer had bother his/her a r s e to sell a car I might have had an i3 with range extender.

I do a 30 mile commute each way, plus the occasional longer run.

My hybrid isn't plug in, its only a 48 volt motor in the trans that kicks in at low engine speeds to fill in the lack of torque.

It also operates the stop/start, which is brilliant.

It will not run on electric alone.

D

re: Mileage results & random EV musings

AndyRKett said:

300miles on a standard charge, 200 mile journey will leave you with about ~100 miles of range left, and having a read about, off a standard 13A socket you get about 30 miles range per hour of charge so that would more or less fully recharge the car over night.

3-4 hours fully charged if you have a dedicated charger installed at home (30A) and 75 mins from a tesla super charger.

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Those numbers just don't add up. A 13A socket will give you about 3kW; a 30A dedicated charger will give you about 7kW. Fully recharging an 85kW battery from a 30A charger is going to take at least 12 hours, and going 30 miles on 3kWhr isn't likely in the real world. 3kW is about 4HP; I'd expect a Tesla will need more than that to cruise at 30mph.

re: Mileage results & random EV musings

jrkitching said:

Those numbers just don't add up. A 13A socket will give you about 3kW; a 30A dedicated charger will give you about 7kW. Fully recharging an 85kW battery from a 30A charger is going to take at least 12 hours, and going 30 miles on 3kWhr isn't likely in the real world. 3kW is about 4HP; I'd expect a Tesla will need more than that to cruise at 30mph.

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You're quite right, the 30 miles per hour range appear to be off a US plug which is apparently 50A (struggling to look this up as on my phone) lots of information as there are so many ways to charge these cars the information isn't clear.

Some cars have duel chargers and it's not clear again if you could for example plug your car into two separate sources at the same time to speed up charging.

As for trying to draw a direct comparison between the Kw and Hp you can't say "I put 3 kw of charge in and therefore have only 4hp output at the wheels. The full power of the vehicle is available it's the duration you can use it for that will be altered. So for example the 85Kw car had a range of 265miles which at 60mph would equate to about 4.4 hours of driving ~20kw use per hour. So if you only put in 10kw you'll only get about 30 minutes at 60mph. At 3kw you'll get about 6-7 minutes at that speed which is still enough to get you 6-7 miles. When you're charging the battery the you could say you're putting In 3Kw of electrical power, at any given moment in time, which is equivalent to 4.1 mechanical horse power. You could with a 100% efficient electric motor connected directly to the mains drawing 3kw, power a 4hp electric motor continuously. When you are charging a battery then the hours of charging can then be concentrated so you may only get a short period of driving, compared to the hours of charge you put in.

With a lot of places now there are many readily available charging points that if needs be you can park up and charge your car at a much faster rate, super chargers for example at 120kw hence them charging a battery to 100% in such a short space of time.

re: Mileage results & random EV musings

jrkitching said:

Depends what you mean by a domestic supply.

You'll still need to have a proper charging point installed; there's no way you're going to fully recharge an 85kW battery pack from a 13A socket overnight.

So driving a couple of hundred miles to your parents house, plugging into the wall and driving home next morning isn't going to work.

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To do the sums, assuming a 85kWh (Tesla S medium) and about 94% charger efficiency gives 90kWh energy required. Say 3000W maximum from a UK domestic socket (13A 231V) give a minimum charge time of 30 hours for a full charge with a range of 265 miles.
So my recent trip to Edinburgh (750miles) that took less than two days in a Croma would need two full charges to be safe. Even at a supercharger that's about 3 hours if fully charged at start and the supercharger is in the correct location. I'm sceptical that even a supercharger can put 85kW into a battery at one go due to heating in the battery. It would be interesting to know the real maximum charge rate for a battery that has just come off a hard motorway run on a hot day. The charger must control the charge rate depending on battery temperature.


Robert G8RPI.

re: Mileage results & random EV musings

AndyRKett said:

You're quite right, the 30 miles per hour range appear to be off a US plug which is apparently 50A (struggling to look this up as on my phone) lots of information as there are so many ways to charge these cars the information isn't clear.

Some cars have duel chargers and it's not clear again if you could for example plug your car into two separate sources at the same time to speed up charging.
<SNIP>

.

Click to expand...

30 miles per hour is for an American 220V (domestic high power, basically two 110V split phase supplies) two dedicated outlets (25A each) and dual chargers on the car (more cost). total power 11kW (excluding charger efficiency so 7.7H for 265Miles = 34miles per hour so 30 sounds about right.
You won't get 50A from a UK domestic supply (single phase) highest standard spur (still a special installation) would be 32A so 7.4kW = 12 hours (inc charger losses) or 22 miles driving per hour charging.
If you went to an industrial 3 Phase 25A supply (have to dig the road up to get this to your house) you could get up to the US figure. A 32A 3 Phase (415V) supply will give you 22kW or about 4H to charge (need to buy a supercharger).


Robert G8RPI.

re: Mileage results & random EV musings

g8rpi said:

I'm sceptical that even a supercharger can put 85kW into a battery at one go due to heating in the battery. It would be interesting to know the real maximum charge rate for a battery that has just come off a hard motorway run on a hot day. The charger must control the charge rate depending on battery temperature.

Click to expand...

If someone told you the sky was blue you'd not believe them.

Batteries are water cooled, so heat is not a problem, tesla learned from this in the 2000s with the roadster and its battery overheating issues. These batteries have also been found to be very durable and reliable, and are the same batteries used in the tesla power wall.
The cars have an 8 year unlimited mileage warranty on both the battery and the motors

Supercharging stations in several locations along the M6 and the M1 as well as in Edinburgh so you would have been fine, the car even sends you a notification on your phone when it's done charging.

re: Mileage results & random EV musings

jrkitching said:

It won't be perfect, but a well designed EV or hybrid with effective regenerative braking will be significantly better than a fossil fuelled car in this regard.

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I don't disagree with you at all in theory.

The trouble with hilly counties of England, there are bends and you need to brake to slow down, If the roads were fairly straight or with gentle curves, the regen would work fine.

Regen works by letting the regen system slow the vehicle and charge the battery - he longer the better, but if you have to brake, you lose the edge.

Round here, you're either pushing hard to get up the hills, or braking going down them. This is the A and B roads of course. Main A30 or the M5 is different.

Look at the A390 West Devon not far from here for instance.
Count the contours?

Mick.

re: Mileage results & random EV musings

PS
A description of that map from left to right.

Come down the hill to the bridge over the river, and you're on the brakes all the way down because it's a 30mph limit. Let off the brakes, and you'll be doing 45mph+ like many folk. :bang:
More than likely have to stop at the traffic lights in the village.

Then, it's a long way up to Gulworthy, then down all the way round the bends again on the brakes due to the tight corners down to Lumburn.

Then, pulling up hill again to the outskirts of Tavistock.

Coming back the other way is a bit more efficient due to the nice long hill down to the river from Gulworthy. No brakes required if you take your time, until you reach the bridge where it's a give way.

Regards,
Mick.

re: Mileage results & random EV musings

Mick F said:

Regen works by letting the regen system slow the vehicle and charge the battery - he longer the better, but if you have to brake, you lose the edge.

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That's not quite right, but I understand your theory.

Basically with many cars with regenerative breaking (my bluemotion golf included) the car ups the voltage needed to charge the battery when braking, this puts more load on the alternator making it harder to turn, the extra resistance on the alternator helps slow the car, but in a lot of cases this system only kicks in during braking. As when free rolling on the engine on a level road, you don't want the car slowing down too quickly as it tries to charge the battery when not really needed. So the more you break the more you charge the battery. The harder you brake the more the car can up the load to slow more using the alternator.

re: Mileage results & random EV musings

Excellent bit of information there.
Thanks.

re: Mileage results & random EV musings

AndyRKett said:

That's not quite right, but I understand your theory.

Basically with many cars with regenerative breaking (my bluemotion golf included) the car ups the voltage needed to charge the battery when braking, this puts more load on the alternator making it harder to turn, the extra resistance on the alternator helps slow the car, but in a lot of cases this system only kicks in during braking. As when free rolling on the engine on a level road, you don't want the car slowing down too quickly as it tries to charge the battery when not really needed. So the more you break the more you charge the battery. The harder you brake the more the car can up the load to slow more using the alternator.

Click to expand...

The scientific miracle that is 'back EMF'.

Mind you, this thread has defined 'off on a tangent'!!!!

D

re: Mileage results & random EV musings

AndyRKett said:

If someone told you the sky was blue you'd not believe them.

Batteries are water cooled, so heat is not a problem, tesla learned from this in the 2000s with the roadster and its battery overheating issues. These batteries have also been found to be very durable and reliable, and are the same batteries used in the tesla power wall.
The cars have an 8 year unlimited mileage warranty on both the battery and the motors

Supercharging stations in several locations along the M6 and the M1 as well as in Edinburgh so you would have been fine, the car even sends you a notification on your phone when it's done charging.

Click to expand...

My Croma is water cooled, but it's not exactly cool. I said I was sceptical and it would be nice to know the actual maximum charge rate. One thing that makes me sceptical is that Tesla only seem to talk about "adding 170 miles in 30 minutes" or similar, not how long it takes for a full charge.
Water cooling cannot take the battery below ambient (or even close to it according to the laws of thermodynamics). Cold weather is also an issue for charging. There are several main variations of Li-Ion battery chemistry, Tesla appear to use NCA in their cars (the "Wall" is different) but the exact chemistry is a commercial secret. So It's very hard to tell eactly what it is capable of. I did not go on the M1 or M6 on my journey up to Edinburgh and the Motel were I stayed overnight did not have any charging facilities never mind Supercharge. An EV is just not practical for me even without the cost. The extra 20kWh battery capacity is around £10,000 alone. That buys a lot of miles in a Croma, about 60000 including buying the car.

Robert G8RPI.

re: Mileage results & random EV musings

g8rpi said:

The extra 20kWh battery capacity is around £10,000 alone. That buys a lot of miles in a Croma, about 60000 including buying the car.
.

Click to expand...

And produce 19tons of CO2 in the process

re: Mileage results & random EV musings

rallycinq said:

Mind you, this thread has defined 'off on a tangent'!!!!

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So much so that, when I first read post 48 my first reaction was to reach for the 'off topic' flag!

I've edited the thread title, as that'll take about 1% of the time it'd take to tidy this lot up.

AndyRKett said:

And produce 19tons of CO2 in the process

Click to expand...

So how does the Tesla compare? Assuming gas powered generation the electricity generated to charge a Tesla comes out at 0.16 kg per mile (based on 500g per kWh and no allowance for distribution, or charging lossses). Thus 60000 miles in a Tesla is 9.6 tons About half that of the Croma. some of the production will be coal and some renewables but 500g/kWh is a good average from https://www.parliament.uk/documents/post/postpn_383-carbon-footprint-electricity-generation.pdf.
So the Croma's not that bad.
I decided to check your 19t figure
https://people.exeter.ac.uk/TWDavies/energy_conversion/Calculation of CO2 emissions from fuels.htm says 2.68 kg/litre for Diesel, that's 12.17 per UK gallon. Current Croma cnsumption over 1500miles is 45MPG (mostly on commute to work) so thats 0.27kg per mile so more like 16.2 tons for 60,000 miles. Interstingly the Exeter university paper gives 43kg/kWh for "Grid Electricity" which would make the tesla 13.8kg/mile or 817 tons for 60,000 miles In reality I thin they are roughly comparable on CO2.
"lies, damm lies and statistics"

Robert G8RPI.

g8rpi said:

So how does the Tesla compare? Assuming gas powered generation the electricity generated to charge a Tesla comes out at 0.16 kg per mile (based on 500g per kWh and no allowance for distribution, or charging lossses). Thus 60000 miles in a Tesla is 9.6 tons About half that of the Croma. some of the production will be coal and some renewables but 500g/kWh is a good average from https://www.parliament.uk/documents/post/postpn_383-carbon-footprint-electricity-generation.pdf.
So the Croma's not that bad.
I decided to check your 19t figure
https://people.exeter.ac.uk/TWDavies/energy_conversion/Calculation of CO2 emissions from fuels.htm says 2.68 kg/litre for Diesel, that's 12.17 per UK gallon. Current Croma cnsumption over 1500miles is 45MPG (mostly on commute to work) so thats 0.27kg per mile so more like 16.2 tons for 60,000 miles. Interstingly the Exeter university paper gives 43kg/kWh for "Grid Electricity" which would make the tesla 13.8kg/mile or 817 tons for 60,000 miles

In reality I thin they are roughly comparable on CO2.
"lies, damm lies and statistics"

Click to expand...

The grid right now is generating 241g CO2 per KWh (per unit)

The tesla requires 85KWh charge to 100% (20.48kg CO2)

But on that it will travel (assuming the most popular P85 model) 426Km

So 20,480g/CO2 divided by 426Km gives 48g CO2/Km

Your car is rated in official testing at 187g/Km

So where as the tesla would produce just 2.88 tons of CO2 over 60,000 miles (assuming you could concentrate all those charges needed in that time on the current amount of CO2 being produced as I type this, per KWh.

Your 187g/Km equals about 19tons over 60k miles give or take.....

When they calculate the costs of CO2 generation on the national grid they factor in a lot of information meaning even solar and wind generated electricity has a CO2 impact on that calculation.

I suspect they are not calculating the CO2 impact of transporting diesel all around the world, the cost of drilling and pumping the oil in the first place, the ships lorries and storage facilities all use to move that oil around and store it, as well as the costs and energy used to refine the diesel from crude oil.

If you factored all of these things into the calculation for your car's tail pipe emissions it would work out considerably higher than 187g/km you travel......

You probably need to quit your job with the Singapore transport ministry...
https://electrek.co/2016/03/10/tesla-model-s-singapore-emissions/

AndyRKett said:

The grid right now is generating 241g CO2 per KWh (per unit)
Reference?
The tesla requires 85KWh charge to 100% (20.48kg CO2)
OK
But on that it will travel (assuming the most popular P85 model) 426Km
How about consitent units = 265m
So 20,480g/CO2 divided by 426Km gives 48g CO2/Km
OK and = 77.4g/m 4.46t
Your car is rated in official testing at 187g/Km Combined? Urban?
I was using real figures)

So where as the tesla would produce just 2.88 tons of CO2 over 60,000 miles
NO it is 4.46t for 60,000 miles, you have multiplied g/km by 60000 km not miles
(assuming you could concentrate all those charges needed in that time on the current amount of CO2 being produced as I type this, per KWh.

Your 187g/Km equals about 19tons over 60k miles give or take.....

When they calculate the costs of CO2 generation on the national grid they factor in a lot of information meaning even solar and wind generated electricity has a CO2 impact on that calculation.
Again were is your 241g/kWh coming from

I suspect they are not calculating the CO2 impact of transporting diesel all around the world, the cost of drilling and pumping the oil in the first place, the ships lorries and storage facilities all use to move that oil around and store it, as well as the costs and energy used to refine the diesel from crude oil.
And what about transporting the coal / gas (most comes by sea from the middle east) Mining, transmission losses etc.
If you factored all of these things into the calculation for your car's tail pipe emissions it would work out considerably higher than 187g/km you travel......
As would the Tesla and it has the extra environmental load of produving batteries etc.
You probably need to quit your job with the Singapore transport ministry...
https://electrek.co/2016/03/10/tesla-model-s-singapore-emissions/

Click to expand...

I don't work for STM but their 500g/kWh is the same as the UK government report figure I used.
Electrec's 188kWh/km s a bit more optimistic than your 199.5 but still give 145g/mile or 8.7 tons still closer to my calculation than yours.
Any way you look at it the Tesla is far from carbon neutral.

Robert G8RPI.

g8rpi said:

I don't work for STM but their 500g/kWh is the same as the UK government report figure I used.
Electrec's 188kWh/km s a bit more optimistic than your 199.5 but still give 145g/mile or 8.7 tons still closer to my calculation than yours.
Any way you look at it the Tesla is far from carbon neutral.

Robert G8RPI.

Click to expand...

You're right I multiplied by 60,000 miles and not 96,560km and that's 4.6t/60k miles. Still nearly 15t less CO2 than your car.

The current CO2 per KWh comes from the ecotricity website as a quick current snapshot that said there are plenty of websites with similar data available if you have a little look about, I find it entertaining your ability to come up with the most obscure unreferenced piece of data on a university of Exeter server, but you can't find something readily available all over the Internet when it goes against your claims.

With the longevity of battery technology being proven and tested in the likes of the Prius for many years, the tesla battery can be expected to give many years reliable service. The price of a tesla is high and they are still highly sort after on the second hand market, meaning that these cars will likely go on for many years and not be scrapped like many cars after 5-10 years. The longevity of a cars working life has a massive impact on the overall CO2 output in the lifetime of the vehicle. An old big fiat does not generally last very long, and the bigger engined 2.4 Diesel croma is now nearly worthless due to tax banding meaning many get scrapped in perfectly good useable condition, and people buy a new car with all the associated CO2 emissions that come with building a new car. This will offset a lot of those emissions produced by battery manufacturing.

The process for calculating the CO2 costs of power generation, DOES factor in all associated emissions from mining and transportation hence wind power still having an associated CO2 emission attached to it.
These calculations don't apply to your croma.


You are now trying to argue that your old croma Diesel is better for the environment than a new all electric car, against any evidence presented, it's verging on delusion.

As I stated you'd argue against the colour of the sky if someone told you it was blue, hell bent on being right even at the cost of any integrity you once may have had.

1/ Ecotricity, yeh they are unbiased and have no agenda - not.
2/ Can't compare Prius batteries, they are Nickel Metal Hydride not Li-Ion (did I tell you I first looked at electric vehicle technology back in the 80's when Sodium-Sulphur was the next big thing) and they are a hybrid car not plug-in.
3/ I don't drive a 2.4
4/ I'm not saying that the Croma produces less CO2 than a Tesla (it's about 80% more) or is better for the environment, I'm just refuting your 19 ton CO2 figure and the implication that the Tesla's footprint is next to nothing.

Robert G8RPI.

g8rpi said:

1/ Ecotricity, yeh they are unbiased and have no agenda - not.
2/ Can't compare Prius batteries, they are Nickel Metal Hydride not Li-Ion (did I tell you I first looked at electric vehicle technology back in the 80's when Sodium-Sulphur was the next big thing) and they are a hybrid car not plug-in.
3/ I don't drive a 2.4
4/ I'm not saying that the Croma produces less CO2 than a Tesla (it's about 80% more) or is better for the environment, I'm just refuting your 19 ton CO2 figure and the implication that the Tesla's footprint is next to nothing.

Robert G8RPI.

Click to expand...

1. data comes from multiple sources and it published so that people can put their washing machines on when the grid is producing the least amount of CO2 per KWh, I'm not sure from your implication of bias, what they would be bias about ? (Please don't answer, I couldn't give a toss consider it a rhetorical question)

2. Nickel metal hydride batteries have a lower battery life than comparable lithium batteries, the implication of this is that if they have been proven to be reliable in a Prius for the last 20 years then it's reasonable to expect even more from the tesla's lithium battery.
So far for all your claims of being a chartered engineer and what you've done in the past, you've said nothing to convince me that you know anymore about these subjects than what you can find on google, which you prove when you can't find easily available sources or when you come out with obscure sources to try and prove something.

3. Didn't say you did but the croma is a rapidly depreciating car and there are few about now as they're not worth people keeping them running, the 2.4 diesel being an example I used as the tax to put it on the road for a year is nearly as much as the car is worth. Certainly when a car is worth £1000 the sort of people buying that car won't be paying £500 road tax. At no point did I say you owned one, this is why you need to actually read before you reply.

4. There was no claim made that the tesla was carbon neutral or made of pixie dust or any other claim, all I said was your car produces 19t of CO2 based on the figures obtained for tax banding, if that's 10tons or 25 tons I don't really care, the 19t figure is likely to be seriously inaccurate as it's based on modern economy cycle testing and is most likely a gross underestimate, essentially all you want to do is argue and try to prove me wrong on something, somehow and you don't care what it is, this seems to be because you really don't know what you're talking about, you've shown this repeatedly been called on it and now you need to mend your dented pride.

You go on about electric cars in the 80s but know nothing about modern day cars, you doubt official charging figures and dispute everything presented without looking anything up yourself. I'm not interested in your dented pride and not interested in arguing about nothing at all. When you know something maybe try looking something up rather than trying to just find something to prove your point, get back to me.