1184 replies to this topic

[mariner]

The article below should not be taken as a condemnation of EV's and Hybrid's as a similar  bulletin on the " new" petrol car if we only had EV's would look similarly dramatic 

 

You have to go to page 10   to start the bit on treatment of hybrids in crashes etc but a " Joe Public" reading it might never buy a Hybrid or EV!

 

https://www.msauk.or...shalnov2014.pdf

Edited by mariner, 02 December 2017 - 14:33.

[Greg Locock]

I think on balance I'd rather work on 300V electrics than a crashed car with a leaking petrol tank. Of course a hybrid gives you both at once.

[Kelpiecross]

I have noticed in the F1 race broadcasts that sometimes they tell the driver over the radio of a broken-down car not to put one foot on the ground and on the car at the same time - but to stand on the car and jump clear. I imagine a crashed road EV could just as dangerous.

[gruntguru]

That's if the supply is DC. For AC -- and high power electrical supplies are almost always AC -- the calculation is more complicated. Let's make it 15,000 Amps as a guesstimate.

Watts = Volts x Amps for AC circuits too when there is no reactive load ie Power factor = 1.0

Power factor for large battery chargers should approach 1.0.

 

"California’s PF Standards for Battery Charging Systems. 

The CEC has adopted requirements of 0.90 PF to improve efficiency in large battery charger systems aimed at non-consumer electronics and in small battery systems aimed at consumer and non-consumer electronics. California estimates it will save 150 GWh to 575 GWh per year by regulating PF in battery charger systems. In addition to PF, these standards cap maintenancemode power and no battery-mode power, and the total amount of energy allowed in a charge cycle. (See Figure 3 for a summary of new battery charging system energy efficiency requirements). Since large battery chargers spend much of their time in charge mode, improvements are required in power conversion efficiency and PF. For small battery chargers, the standards focus on improving efficiency in charge return Factor and in the more common maintenance mode."

 

From https://www.iotaengi...ry Chargers.pdf

Edited by gruntguru, 04 December 2017 - 03:33.

[MatsNorway]

I have noticed in the F1 race broadcasts that sometimes they tell the driver over the radio of a broken-down car not to put one foot on the ground and on the car at the same time - but to stand on the car and jump clear. I imagine a crashed road EV could just as dangerous.

I think that is mostly because it is a largely carbon fiber based frame. Something about not getting grounded once the circuitry is being broken. In a crash you are suddenly the leader to ground. Probably some differences vs. Alu/steelframe cars.  I can not really argue or defend it. Just a thought.

Edited by MatsNorway, 05 December 2017 - 15:56.

[ray b]

my el experiments went up in smoke when I tried to hook two Li- batteries  from 18v/20 peak volts  power tool packs together

one let the smoke out the other just went dead when hooked up in parallel to cut the amp draw heating a single unit produced

 

I was trying to power a 12v bike motor that had a 12 volt lead/acid original to both get a bit more power and less weight

and I had the power tool packs on hand so no cost experiment I thought

the bike motor and wires  survived fine

[ray b]

I think that is mostly because it is a largely carbon fiber based frame. Something about not getting grounded once the circuitry is being broken. In a crash you are suddenly the leader to ground. Probably some differences vs. Alu/steelframe cars.  I can not really argue or defend it. Just a thought.

carbon fiber boats/masts/ rudder stocks are know to be very good conductors if not shattered

perhaps the problem is not the c/f but the fact it can totally break/shatter and lose connection

[Bloggsworth]

Highly amusing seeing people with electric cars trying to drive them on the ice and snow - 100% torque at zero revs is no help at all...

 

As an aside - Traction control that doesn't work under the same conditions is functionally useless, as it is the time when it is most needed. Didn't work on my Mazda, doesn't work on my Skoda either.

Edited by Bloggsworth, 13 December 2017 - 13:46.

[gruntguru]

 In what way are the torque characteristics of an internal combustion engine superior?

[ray b]

I just stay south of ice and snow in s Fla

[Tenmantaylor]

Highly amusing seeing people with electric cars trying to drive them on the ice and snow - 100% torque at zero revs is no help at all...

 

As an aside - Traction control that doesn't work under the same conditions is functionally useless, as it is the time when it is most needed. Didn't work on my Mazda, doesn't work on my Skoda either.

 

As ever - tyres make more difference than drivetrain/engine/wheel size/weight. I'd put lots of money on a 4wd model S on winter tyres being an excellent winter car.

 

Don't take my word for it

 

[Greg Locock]

EVs are more likely to have low rolling resistance tires. Which means that they will sacrifice things like wet and dry grip, and tread pattern.

[scolbourne]

Electric cars are very popular in Norway which has more snow than most places in the world. We should hear how they perform over there and whether the cold causes many problems for the batteries.

[Greg Locock]

..and do they get the same tires as American EVs?

[MatsNorway]

Teslas are high end products tho. You expect it to do that well or ok at least. A motor controller can be made quite crude.. Just like injection systems can.

Edited by MatsNorway, 14 December 2017 - 19:01.

[Bloggsworth]

As ever - tyres make more difference than drivetrain/engine/wheel size/weight. I'd put lots of money on a 4wd model S on winter tyres being an excellent winter car.

 

Don't take my word for it

 

 

4WD makes even more difference - I've yet to see a 4WD Nissan Leaf.

 

Electric motors don't do idle, so you can't feed in the power very gently via the clutch at idle revs and move off without spinning the wheels.

[Bloggsworth]

Electric cars are very popular in Norway which has more snow than most places in the world. We should hear how they perform over there and whether the cold causes many problems for the batteries.

 

And snow tyres, chains, studded tyres - not common in the UK.

[Greg Locock]

electric motors pick up from  idle perfectly well, if you don't give them any current they deliver no torque. Where do you get this stuff?

[Bloggsworth]

electric motors pick up from  idle perfectly well, if you don't give them any current they deliver no torque. Where do you get this stuff?

 

They don't idle in the same sense as IC engines - Or are you telling me that they have fluid flywheels and are constantly spinning while the cars are at rest? The one I helped get moving (by the old fashioned method of pushing) was either off or powering the wheels, nothing in between - As soon as he touched the accelerator pedal it spun the wheels.

[Greg Locock]

That's a calibration issue not a function of it being an electric motor. They need to ramp the current more slowly on initial tip in, or have a snow switch.

[Wuzak]

That's a calibration issue not a function of it being an electric motor. They need to ramp the current more slowly on initial tip in, or have a snow switch.

 

That is a potential benefit of EVs - you can give them modes where there are aggressive or very gentle power ramp ups. 

 

I assume that cars such as the Tesla use a softer ramp than the motors are capable of, so that less than sensitive drivers don't go spinning the wheels up all over the place.

[Greg Locock]

There is a famous brand of car whose throttles are rather linear. Their Australian customers complain because they have to apply full throttle (pedal) to get full throttle(engine). You'd probably be surprised by how much effort went into designing the snail cam on a carburetted engine.

[MatsNorway]

When do you actually need the aggressive setting tho? Randy Pobst on motortrend YT stated he did not like the "racy" profiles because they did nothing but upset the car more easily. At the very least you want a smooth ramping up. And i guess that is reasonable as you get more and more powerful cars.

Edited by MatsNorway, 15 December 2017 - 08:09.

[Bloggsworth]

That's a calibration issue not a function of it being an electric motor. They need to ramp the current more slowly on initial tip in, or have a snow switch.

 

Who are the "They" who need to ramp? The designers or the drivers?

[gruntguru]

The drivers can't do much about "calibration issues".

 

Point is 100% torque at zero rpm is only available with pedal fully depressed. How much torque is supplied when the driver moves the go pedal 2% is a calibration and perhaps motor-control issue.

[Charlieman]

BP has purchased a UK provider of electric vehicle charging points (Chargemaster) for £130 million. These are high current/high power charging points which obviously require a lot of infrastructure to support. Earlier this year, Chargemaster attempted to raise £50 million from investors which would have valued the business at £170 million.

https://www.theguard...etwork-for-130m

 

Following the acquisition, 6,500 Chargemaster points are each valued at a bit less than £20,000. Ouch. The number of pure EVs and hybrid EVs (i.e. ones with a charging socket) in the UK is 140,000 in 2018; let's assume that it is 7,000 charging points and 210,000 cars (30:1 ratio) in a few years time and we still value a charging point value of £20,000. Is it possible to pay the interest on £20,000 from revenue?

[blkirk]

When do you actually need the aggressive setting tho? Randy Pobst on motortrend YT stated he did not like the "racy" profiles because they did nothing but upset the car more easily. At the very least you want a smooth ramping up. And i guess that is reasonable as you get more and more powerful cars.

 

I read that Randy Pobst quote in an article he wrote for the SCCA magazine.  I agree with him 100%.  Manufacturers make fast opening throttles because it makes their cars feel fast on the test drive.  The rest of the time, they are a pain to live with. 

I hooked up an OBD-II reader to my car once to record speed and throttle position on my drive home. The throttle position only had to be at 12% to cruise at 65 mph.  15% throttle got me to 80 mph.  That makes trying to drive a sane speed very, very difficult.  By the time I feel my foot touch the accelerator, I'm doing 30 MPH which makes school zones a joy.  If I feel the accelerator move, I'm rapidly approaching highway speeds.  Anything beyond that is WOT with the only difference being higher shift points.

I think the engineers mapped accelerator position to power instead of the accelerator-to-torque mapping we're all used to from the time before electronic throttles.

[gruntguru]

The throttle position program should be selectable. Test-drive mode, track-day mode, sensible mode. . . .

[gruntguru]

BP has purchased a UK provider of electric vehicle charging points (Chargemaster) for £130 million. These are high current/high power charging points which obviously require a lot of infrastructure to support. Earlier this year, Chargemaster attempted to raise £50 million from investors which would have valued the business at £170 million.

https://www.theguard...etwork-for-130m

 

Following the acquisition, 6,500 Chargemaster points are each valued at a bit less than £20,000. Ouch. The number of pure EVs and hybrid EVs (i.e. ones with a charging socket) in the UK is 140,000 in 2018; let's assume that it is 7,000 charging points and 210,000 cars (30:1 ratio) in a few years time and we still value a charging point value of £20,000. Is it possible to pay the interest on £20,000 from revenue?

No doubt such acquisitions are speculating on the coming EV population explosion. In the meantime, using your numbers, revenue would be:

210,000 (veh) x 10,000 (miles/annum/veh) x 3 (kW.hr/mile) x 0.15 (£/kW.hr) / 7,000 (charging points) = £135,000.00/charging point/annum. A 10% margin would therefore provide gross profit of £13,500.00/charging point/annum.

 

Worst assumption in the above analysis is that all 210,000 vehicles use only the 7,000 charging points in question. Obviously there will be other outlets including charging at home.

[Greg Locock]

You wouldn't believe how much work used to go into the throttle progression on cable type systems. We had different snail cams for manuals and autos, in development, and one job was to get rid of that difference. It gets much more difficult with more powerful engines.

 

Once you have drive by wire then there is no excuse, it just takes time for a calibrator to build a table of pedal position vs rpm vs road speed vs gear vs time vs ECT vs injector pulse width. Which as you can see is non trivial.

 

A lot of these lookup tables are now replaced by mini simulators. Basically the driver input goes into a simple systems model and the desired outputs emerge. 

[MattPete]

In the opposite, all BMW automatics I have driven (prior to the 8-speed ZF and Aishin autos they use now) had extremely lethargic tip-in*, which felt dangerous when trying to pull-out into traffic. The solution was either to mash the throttle to the floor (and then back off quickly), or put it into sport mode, and switch back into normal mode once into traffic.

 

Now that I think about it, all of the BMWs 8-speeds with good throttle tip-in have been turbos (current 3-series, 1-st gen X1, 2nd-gen X2).  I did get a 320 non-turbo loaner with the ZF8, and it also had a lethargic tip-in from a stop.  It's been decades since I've driven a turbo, and to me it's weird that the normally aspirated engined car felt laggy and the turbos did not.

 

 

* compared to my manual BMW, manual Civic, manual G20, auto Mazda5, auto Honda Odysey, and every automatic Japanese or American rental car I've ever driven.

[Kelpiecross]

No doubt such acquisitions are speculating on the coming EV population explosion. In the meantime, using your numbers, revenue would be:
210,000 (veh) x 10,000 (miles/annum/veh) x 3 (kW.hr/mile) x 0.15 (£

/kW.hr) / 7,000 (charging points) = £135,000.00/charging point/annum. A 10% margin would therefore provide gross profit of £13,500.00/charging point/annum.
 
Worst assumption in the above analysis is that all 210,000 vehicles use only the 7,000 charging points in question. Obviously there will be other outlets including charging at home.

"the coming EV population explosion" - don't hold your breath. Wishful lefty thinking.

[BRG]

Oh good, an electric car version of the VW emissions cheating?

 

So it takes far longer to charge and doesn't go nearly as far as they told you it would.  Some things never change in the auto industry.

[kikiturbo2]

while I find it interesting that Leaf would change the charging current on purpose, to save the battery... the complaint about the range doesnt stand really.. range depends on average power consumption... what we have to get used to is the fact that power consumption rises with the square of vehicle speed... as a consequence, EVs will tend to use more energy on long distance drives at highway speeds than in town..

[Charlieman]

No doubt such acquisitions are speculating on the coming EV population explosion. In the meantime, using your numbers, revenue would be:

210,000 (veh) x 10,000 (miles/annum/veh) x 3 (kW.hr/mile) x 0.15 (£/kW.hr) / 7,000 (charging points) = £135,000.00/charging point/annum. A 10% margin would therefore provide gross profit of £13,500.00/charging point/annum.

 

Worst assumption in the above analysis is that all 210,000 vehicles use only the 7,000 charging points in question. Obviously there will be other outlets including charging at home.

How long does it take to charge a car? How many cars and pounds per day?

 

Chargemaster owns many charging points at posh hotels, not enough at on the road top up stations.

 

Chargemaster professes to have "50,000 customers". Hmm? Is that 50,000 vehicles registered to use the service? Trusted by councils and businesses, when it is evident that the Chargemaster customer numbers are themselves amalgamated. How many councils and businesses, and how many individuals?

 

Most of Chargemaster's customers are "what if I get close to the middle of nowhere" thinkers who normally charge up at home or at work.

 

Let's see.