Electric vehicles

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#1324254 13-Jun-2015 22:08

dwl:
+1 Using EPA figure of one US gallon of petrol having 33.7 kWh of energy and the Leaf having only a 24 kWh battery pack (energy in only 3 litres of petrol), that gives 130-160 km of driving, the difference in EV energy use compared to petrol (especially V8) is dramatic.

Internal combustion engines are horrendously inefficient at converting the chemical energy in petrol into kinetic energy... I think only 35% efficient or so. Electric motors are IIRC 97% efficient. So a 24kWh battery will give you the same range/power as about 9 litres of petrol.

JWR

821 posts

Ultimate Geek

#1324262 13-Jun-2015 22:25

frankv:
dwl:
+1 Using EPA figure of one US gallon of petrol having 33.7 kWh of energy and the Leaf having only a 24 kWh battery pack (energy in only 3 litres of petrol), that gives 130-160 km of driving, the difference in EV energy use compared to petrol (especially V8) is dramatic.

Internal combustion engines are horrendously inefficient at converting the chemical energy in petrol into kinetic energy... I think only 35% efficient or so. Electric motors are IIRC 97% efficient. So a 24kWh battery will give you the same range/power as about 9 litres of petrol.

I know petrol engines are not that efficient. Too much heat loss.

But, I doubt electric motors are anywhere near 97% either. There is also heat loss.

However, with electric, it is possible to recover energy when slowing/braking.

Most of the time, petrol motors accelerate, then slow soon after... wasting all the kinetic energy just gained.

I do see hybrid machines becoming a lot more popular in the near future.

If the internal combustion part was powered by hydrogen, then that would solve most of the environmental problems from cars.

All electric will probably only take over if battery storage can be considerably improved.

Fred99

13684 posts

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#1324282 13-Jun-2015 23:03

JWR:
frankv:
dwl:
+1 Using EPA figure of one US gallon of petrol having 33.7 kWh of energy and the Leaf having only a 24 kWh battery pack (energy in only 3 litres of petrol), that gives 130-160 km of driving, the difference in EV energy use compared to petrol (especially V8) is dramatic.

Internal combustion engines are horrendously inefficient at converting the chemical energy in petrol into kinetic energy... I think only 35% efficient or so. Electric motors are IIRC 97% efficient. So a 24kWh battery will give you the same range/power as about 9 litres of petrol.

I know petrol engines are not that efficient. Too much heat loss.

But, I doubt electric motors are anywhere near 97% either. There is also heat loss.

However, with electric, it is possible to recover energy when slowing/braking.

Most of the time, petrol motors accelerate, then slow soon after... wasting all the kinetic energy just gained.

I do see hybrid machines becoming a lot more popular in the near future.

If the internal combustion part was powered by hydrogen, then that would solve most of the environmental problems from cars.

All electric will probably only take over if battery storage can be considerably improved.

The 35% efficiency cited for ICE is at "optimal" revs/load. Most of the time, they are far less efficient than that.
One big bonus for EV - they don't need horrendously complex and/or inefficient transmissions to optimise engine RPM/load.

raytaylor

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#1324330 14-Jun-2015 09:01

robjg63: NZ is ideally suited for EVs.

we take generally short trips by international standards

My flatmate is from holland. He says that when me and him drive to wellington, back home he would have gone through two other countries over the same amount of time/distance.

Driving from napier to hastings (20kms) would be a weekend-only trip, where as many people in hawkes bay drive the distance multiple times a week.

Ray Taylor

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old3eyes

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#1324335 14-Jun-2015 09:04

MikeB4: The pedestrian warning sound should be compulsory and Protected from tampering

How do you get on then when a trolley bus is coming along?? They don't have warning devices. If people can't look when they cross a road then don't go out..

Regards,

Old3eyes

raytaylor

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#1324344 14-Jun-2015 09:19

So I see a few innovations that could make a very big difference

1) Solar powered roads.
There is a company in europe that has placed a transparent plastic with a surface exactly like chipseal. So it is shaped and gives the same grip as a standard chipseal road.
The idea is to power nearby homes and street lamps.

2) Toothbrushes
If the government wants to maintain road user charges, they can combine solar powered roads with induction coils in the road to receivers on the bottom of cars.
A typical car has a large amount of clear roadspace in front and behind it. These exposed, uncovered solar cells in the road can provide supplement power for the car driving down the road, by means of induction coils. This reduces draw from onboard batteries and extends their life.

Cells can be clipped together like pre-school play tiles to form a road surface. Also heavier duty cables can be laid below to transport the power over some distance, or to an export metering point.

3) Solar cell paint
Similar to what you see in the australian solar race, cars can be coated with solar cells so when you park them in a mitre 10 car park (which it seems there is a law banning any shade-creating trees) the hot sun can actually do some good for your car.

4) Solar export metering and wind
Some here complain that our power supply is based on hydro supplemented with coal.
However with the increase in solar or wind export metering, it means that the hydro demand is reduced during daylight hours. Coal can eventually be switched off, then hydro output lowered, which increases water reserves for night-time use.

Ray Taylor

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Spreadsheet for Comparing Electricity Plans Here

grant_k

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#1324347 14-Jun-2015 09:32

raytaylor: ...
4) Solar export metering and wind
Some here complain that our power supply is based on hydro supplemented with coal.
However with the increase in solar or wind export metering, it means that the hydro demand is reduced during daylight hours. Coal can eventually be switched off, then hydro output lowered, which increases water reserves for night-time use.

I think you'll find that coal was switched off some time ago. Huntly power station is the only remaining one I'm aware of that originally used coal, however its 3 remaining generating units have been converted to natural gas over the past decade or so. Meremere used coal exclusively, however it was demolished many years ago.

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Linuxluver

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#1324355 14-Jun-2015 09:45

I'm thinking of getting a Nissan Leaf....and seeing just how well it performs around Auckland.

I mainly use public transport anyway, but the trips that aren't well suited to public transport a Leaf could be just perfect. But it's useless for anything out of town. You can drive to about 90 minutes then charge - fully - in several hours.

Could be useful as a touring car if you just took very short hops and had loads of time. Drive an hour or so to the next town mid day. Book into the motel (easier access to power point - out the window). Charge overnight. 30-50kms of exploring next monring - maybe - then head to next town (max 100km away)...and rinse and repeat.

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tdgeek

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#1324360 14-Jun-2015 10:09

dwl: I think the Leaf has made EVs practical and available but will they be mainstream in NZ short term? No.

I was impressed driving a Leaf in Wellington about the comfort and performance up the hills. The range is fine if you have access to another car for long trips. The cost of recharge, especially if you have low night rate power, is much less than petrol for equivalent distance (e.g. maybe $3 for 130km). The lack of RUC is a big saving.

If you have a daily commute that fits the range (which would be most people) then the total cost of ownership over say 150,000 km for the EV may come out on top if comparing to the cheaper equivalent petrol version using that good pricing for the Leaf. Ideally fill the car up with others in a car pool and the planet will love you.

Without other incentives beyond no RUC I think EVs will be slow to adopt here for the next few years but that doesn't mean they aren't a viable option now. Charging at home is a bonus. It gets down to how much you are prepared to spend to get that "EV smile". I know some who have and are happy.

There will be many who will have lots of reasons why EVs are a bad idea. What about battery life? Jury is stilll out but in the US I believe the price of a replacement pack for the Leaf has been set at not much over US$5k and that will drop with time. The power train is much simpler than petrol in terms of moving parts.

Other thoughts ?

RUC are partly to maintain the roads? If so, then you'd expect they would have to contribute. Hub Odometer, battery replacement cost, high initial cost, may make penetration difficult. Perhaps enforce a monthly auto payment for battery via hub odometer for RUC to allow a scenario where battery replacement is built into daily running costs, thereby invisible when having to replace, or buy/sell an EV

tdgeek

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#1324361 14-Jun-2015 10:12

Linuxluver: I'm thinking of getting a Nissan Leaf....and seeing just how well it performs around Auckland.

I mainly use public transport anyway, but the trips that aren't well suited to public transport a Leaf could be just perfect. But it's useless for anything out of town. You can drive to about 90 minutes then charge - fully - in several hours.

Could be useful as a touring car if you just took very short hops and had loads of time. Drive an hour or so to the next town mid day. Book into the motel (easier access to power point - out the window). Charge overnight. 30-50kms of exploring next monring - maybe - then head to next town (max 100km away)...and rinse and repeat.

Thats a long road trip, but it may change the holiday culture. Solar panels on the roof, bonnet, boot? Or is that too small to matter? Teeny wind driven turbines in the grill? Worth looking outside the square to get every last amp that is feasible.

tdgeek

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#1324364 14-Jun-2015 10:21

JWR:
frankv:
dwl:
+1 Using EPA figure of one US gallon of petrol having 33.7 kWh of energy and the Leaf having only a 24 kWh battery pack (energy in only 3 litres of petrol), that gives 130-160 km of driving, the difference in EV energy use compared to petrol (especially V8) is dramatic.

Internal combustion engines are horrendously inefficient at converting the chemical energy in petrol into kinetic energy... I think only 35% efficient or so. Electric motors are IIRC 97% efficient. So a 24kWh battery will give you the same range/power as about 9 litres of petrol.

I know petrol engines are not that efficient. Too much heat loss. I'd have thought friction from the crank, pistons, valves, gearbox, Diff and anything else that moves thats not in an EV

But, I doubt electric motors are anywhere near 97% either. There is also heat loss.

However, with electric, it is possible to recover energy when slowing/braking. F1 do that , KERS, Kinetic Energy Recover System

Most of the time, petrol motors accelerate, then slow soon after... wasting all the kinetic energy just gained. Thats the driver's issue?

I do see hybrid machines becoming a lot more popular in the near future. My take is that a hybrid carries a lot of friction due to having the drivetrain, and the wasted weight of the standard engine. I'm for a sole EV

If the internal combustion part was powered by hydrogen, then that would solve most of the environmental problems from cars. Yep, agree. Nuclear as well, but that has other disadvantages!

All electric will probably only take over if battery storage can be considerably improved.

k14

629 posts

Ultimate Geek

#1324376 14-Jun-2015 10:59

grant_k:
raytaylor: ...
4) Solar export metering and wind
Some here complain that our power supply is based on hydro supplemented with coal.
However with the increase in solar or wind export metering, it means that the hydro demand is reduced during daylight hours. Coal can eventually be switched off, then hydro output lowered, which increases water reserves for night-time use.

I think you'll find that coal was switched off some time ago. Huntly power station is the only remaining one I'm aware of that originally used coal, however its 3 remaining generating units have been converted to natural gas over the past decade or so. Meremere used coal exclusively, however it was demolished many years ago.

Not quite, there are still 3 units running that can be run on either coal or gas. Generally 1 is available to run on coal, but depending on their gas contracts/coal stockpile they may decide to run on either.

Bobdn

222 posts

Master Geek

#1324378 14-Jun-2015 11:11

Linuxluver: I'm thinking of getting a Nissan Leaf....and seeing just how well it performs around Auckland.

I mainly use public transport anyway, but the trips that aren't well suited to public transport a Leaf could be just perfect. But it's useless for anything out of town. You can drive to about 90 minutes then charge - fully - in several hours.

Could be useful as a touring car if you just took very short hops and had loads of time. Drive an hour or so to the next town mid day. Book into the motel (easier access to power point - out the window). Charge overnight. 30-50kms of exploring next monring - maybe - then head to next town (max 100km away)...and rinse and repeat.

Leaf really interests me but I'm going to wait until 2017 when the range could be 400km or more.

Sideface

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#1324381 14-Jun-2015 11:22

I'm currently driving a Honda hybrid.
It's a pleasure to drive and very economical to run - BUT it was a bad buy for me as I only drive it short distances, once or twice a week.
I last filled the petrol tank 3 months ago.

If I could buy a small all-electric vehicle for the same price as a conventional small car, I would get one for local usage.
But a $60,000 price tag is ridiculous.
I'll wait for half that price.

Sideface

kemosabe

66 posts

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#1324401 14-Jun-2015 12:34

Anybody have or seen an imported Prius PHV (PHEV) in NZ.

2012 models are available second hand in Japan and should be able to be landed in NZ for $22,000 to $25,000 now. Just wonder if there is any compliance issue in NZ for them.

At utpo 25km range per charge, that would do the work run for a fair amount of people (if able to charge at work)

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