OT EV car range

The total energy required to accelerate a car to a certain speed does not depend on how fast the acceleration takes place.

Not particularly fast now, though. Declining in many more affluent countries. Of course according to Ehrlich in 1968:

The battle to feed all of humanity is over. In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now. At this late date nothing can prevent a substantial increase in the world death rate.

I don't buy that.

No chance, that is a lot more faffing around than EVs.

I went to Woking in my Prius (hybrid) a few weeks ago. Setting off for home, the satnav forecast 118 miles distance while the car's computer forecast 118 miles range. Reaching the M1, I restricted speed to 60/65mph, mainly by tucking in behind HGVs, and got to the petrol station one mile from home with 5 miles to spare, allegedly.

When going downhill mine Focus 1.0 displays 99mpg (it's hit its electronic end stop)

The amazing thing about the car, is the battery pack capacity is "ordinary". It's not like they put a Proterra bus pack in there to get that range. It isn't simply a wad of batteries. The drag coefficient is pretty low.

The price of the car will obviously be out of reach. If it went into production, they'd make a fat profit.

And there is at least one project which demonstrated longer range than that, but the economics are not attractive. That used a "solid" battery, where the battery is pulled out of the car and recycled at the end of the trip, at considerable expense. The beauty of the "solid" battery, is you could load a new one at each "gas station". This was purely a concept design, with one cross-country trip as a demo run. It's no more practical than the sometimes-mentioned idea of swapping lithium packs. Which is not going to happen, for safety reasons.

Paul

ICEs have a quite non-flat power curve, so the efficiency changes with revs and gears. If you redline it in first gear the engine isn't working as efficiently as more sensible revs in a higher gear. When you depress the clutch there's the engine revs but no power applied to the wheels at all.

EVs have a much flatter power curve and no gear changes, so it doesn't matter so much the rate of acceleration, the same power is applied at any speed. Therefore it doesn't matter what speed you started at or how fast you gain speed.

The Astra says it's doing 10mpg but that would only apply at constant load - eg if that was the balancing speed up a hill. If you had 10 miles of constant hill you might use a gallon, but most of the time your efficiency would be a lot better once you've got up to speed. Being an ICE there's no regenerative braking so the fact you're now at the top of the ten mile mountain doesn't allow you to recover any of that potential energy going down the other side. (in fact you may have to use more fuel in engine braking, rather than just using the friction brakes)

Theo

That's in theory, in practice, theory is wrong.

Simply because engine efficiency and in an auto box, gearbox efficiency, is not constant with power and rpm and rolling friction is not proportional to the speed.

No need in the first world, NOT ONE is even self replacing if you take out immigration.

Same with India and China COMBINED.

Theo <theom+ snipped-for-privacy@chiark.greenend.org.uk> wrote: Being an ICE there's no

Pretty sure ICE. cars have had over-run fuel shut off for donkey?s years, probably since the advent of electronic fuel injection.

Tim

That is the correct way to drive.

You need a Vauxhall - 999 mpg! ;)

Interesting and good to know that Mercedes are addressing the serious EV problem of range. However, it doesn't say how long it will take to recharge for the next 620 miles. Of course, if you can be sure of overnight charging at an hotel, that probably isn't a problem. I've never used a full tank of fuel in one day's driving either.

I imagine they will be targeting the same people who can afford their S Class models, which are bit out of reach on my pension.

....similar to my 2 litre Golf R

There's always battery trailers :-)

But still forecast to reach 11 Billion. Planet earth is 'on fire' with the existing population. Glad I am my age and not just entering the world of work.

The BMW i3 used to be available with an optional motorcycle engine as range extender.

It's going out of production in July 2022. Not sure if the optional motorcycle engine is still available

I regularly do 220 miles per trip in a car with a tank capacity of 400+ miles. I often do these journey non-stop or with one quick pee break. Planning for a longer break during the journey can often result in hitting rush hour(s) traffic conditions at the end of the journey.

The problem for me with the current crop of EVs is that the quoted range is around the 200 mile mark and probably a lot less on the motorways in mid winter keeping myself warm with the heater, or cool in the summer with AC. I could spend, say, 30 minutes re-charging up mid journey but I live in Essex and have to use the M25 parking lot plus the road into my town is often no better. On a good day my journey can be 4.5 to 5 hours. On a bad day add 3 hours in stop go traffic! How much do you need to recharge mid-journey to cope with the worst possible scenario?

If the range was 620 miles on an affordable car the potential problems go away but in the link I posted at the start of the thread with a real world winters journey at 70+mph seems to indicate that half the manufactures range for a full charge on a new battery may be more realistic. Still, a real 300 mile range in worst case conditions is better than 200 mile range which can only be achieved with a very light foot at much slower speeds.

The USA test figures for the mileage range of European EVs generally are lower. They dynamometer test and don't take the car beyond 60 mph. I cannot find the link I had the other day but this gives some idea of what I found on other sites

No, 9.7B

Bullshit it is.