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Electric Cars

Started by Data, April 07, 2016, 00:01:37 AM

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0 Members and 2 Guests are viewing this topic. Total views: 897,410

Data

Quote from: Carl2 on April 11, 2016, 13:39:05 PM
  I just did a search for electric cars in the US, the first website was from 2013-14,  The Nissan Leaf seemed to have no completion, very easily the largest seller.  The next website was for the electric cars being sold in 2015, giving Prices, Efficiency, Range, Pics, More.  it covers hybrid and 100% elec.  Ranges go from 80 miles to 110, prices seem to be 25,000 to over 30,000, this is from the better models and a vehicle that still resembles a car.
  It seems that " you'll add just about 4 miles of charge or driving range in one hour of charging " and you should buy an "Electric Vehicle Service Equipment" (aka EVSE) and this increases the miles added per hour to about 11 to 22, the cost for the EVSE is about 1000.
Carl2

Carl2, some good info there, thanks  :)

I found this video made by a chap that has had a 1st gen Nissan Leaf for a year now, he gives his opinion well I think, all the pros and cons.

! No longer available

Carl2

  Very good film, nice to hear from a user rather than the advertising department.  I noticed he's getting some free electricity at work.  It's interesting that the higher speeds decrease the efficiency (mpElectricty)possibly some gearing would help that. 
  I can not recall seeing any charging stations anywhere but again I had never looked for any.
Carl2

Data

Quote from: Carl2 on April 12, 2016, 12:54:32 PM
It's interesting that the higher speeds decrease the efficiency (mpElectricty)possibly some gearing would help that. 

I believe that is caused by regenerative braking, city driving is a lot of speeding up and slowing down, the slowing down puts energy back into the battery, that can't happen as much on long distance driving on freeways.

Free charging: I had to look into that and again I'm pleasantly surprised, many cities all over the world have FREE, yes free charging points. In Brighton where I live the charging points are free to use for the public.

QuoteThere are electric vehicle charging points around Brighton & Hove. These are free to use for any electric vehicle that needs to park while charging.

http://www.brighton-hove.gov.uk/content/parking-and-travel/parking/electric-vehicle-charging-points

Carl2

  I was able to get some Info about the efficiency of electric motors from the internet.
"Most electric motors are designed to run at 50% to 100% of rated load. Maximum efficiency is usually near 75% of rated load. Thus, a 10-horsepower (hp) motor has an acceptable load range of 5 to 10 hp; peak efficiency is at 7.5 hp. A motor's efficiency tends to decrease dramatically below about 50% load. However, the range of good efficiency varies with individual motors and tends to extend over a broader range for larger motors, as shown in Figure 1. A motor is considered underloaded when it is in the range where efficiency drops significantly with decreasing load. Figure 2 shows that power factor tends to drop off sooner, but less steeply than eficiency, as load decreases."
  I'm sure the manufacturer has this info and it's likely he had special motors made to his specifications.  Also I certain this is for AC motors while cars would be using DC motors but I'm sure DC motors would have similar efficiencies.
  I also learned they have electric motorcycles but they are pretty expensive.
Carl2

DaveMorton

Carl, is this the source you're citing? Just curious.
Safe, Reliable Insanity, Since 1961!

Carl2

Dave,
  That is the source.
Carl2

DaveMorton

thanks. I found it to be an interesting, if somewhat technical, read. :)
Safe, Reliable Insanity, Since 1961!

Carl2

Gas engines have efficiency and power curves also that varies with RPM, the gas burning cycle varies between 600 rpm and about 3000 rpm so we have a lot of unburnt gasses.  I'm not sure of the latest technologies but I'd guess it is brushless motors with semiconductors connected to the windings. 
Carl2

Snowcrash

I do like the idea of zero emission vehicles but I feel there are some serious issues with battery tech.

The problems as I see them.
1) Assuming all cars being equal on cost to manufacture and running, there is not enough materiel in the world to be able to give everyone who has a car an electric car due to the battery. I think the main lacking element is Cobolt. There are some techs coming through with Lithium/Iron but they're not here yet.
2) Charge rate. Again, some interesting tech coming through with variations of Lithium batteries. Having to wait 12 hours for a full charge is often not practical.
3) Energy density. This is a function of volume/storage capacity/weight. This is going up all the time but (sketchy figures here) only at about 5% per year. We really need this to improve and there's no Moore's law in place. This is your range.
4) Where the energy comes from. To made this tech truly green, the electricity needs to come from green sources. At the moment manufacturing costs (both $$ and green issues) are the main limiting factors. I've put this 4th on purpose.

All in all it's down to the battery.

Most things I see don't seem to mention super capacitors and energy recovery systems. I see this as a complimentary tech that will prolong the range of a vehicle. The energy density of super caps is limited but they can charge/discharge rapidly.
"I cannot remember the books I've read any more than the meals I have eaten; even so, they have made me."

Ralph Waldo Emerson

Data

Some interesting points there Snowy and I agree with 1 and 3 but not 2 and 4.

I agree the batteries should and will get better over time, Nissan have already taken a couple of steps in improving the batteries on the leaf, these newer batteries can be fitted into a 1st gen leafs, no need to get a new car, as the technology improves electric car owners should be able to swap out the batteries.   

2.
Rapid charging or super charging is faster:
QuoteNissan LEAF can charge its lithium-ion battery from 0% to 80% in approximately 30 minutes using a rapid charger; using an approved Home Charging Unit either 8 hours for a 16A unit, or 4 hours using a 32A unit.

Do you always fill up to the top with petrol ?

4. My favorite argument really, putting it simply, its better to take the smog out of our cities and move it out of town, I might even get on my bike then but as things are I would rather smoke then cycle through one of our smog infested towns. Wouldn't it be good to go into town and not smell the exhaust fumes.  

It's funny but the more I look into this the more people I find that have electric cars and actually like them, a lot.  :scratch-head:

Snowcrash

Ok, rapid charging is further ahead than I thought. Hope the battery capacity holds!

QuoteDo you always fill up to the top with petrol ?

With less than 100 mile range... yep. And generally yes, so I don't have to got to the station too often.

I put number 4 in as a side issue as, as a species, we need to get away from an oil economy. Hydrogen economy is banded around but not electric economy (I don't know if that could work). Either way electric cars would have their place.
"I cannot remember the books I've read any more than the meals I have eaten; even so, they have made me."

Ralph Waldo Emerson

Data

Seems to me that this is more about changing peoples preconceptions about electric cars than proving if electric cars are any good.

100 mile range before charging seems fine to me, ok I always do small trips but I would be happy with that. Thousands of charging points across the UK now, free charging in Brighton, never go to a petrol station again, no road tax, little servicing needed, cleaner air in our cities.

It's pros and cons  :good-bad:

I was thinking how unpractical an electric car could be for people that have to park their cars in the street at night, running a charging lead across the pavement over night isn't very practical. That could be a large concern for some people.

Have a look at this video about the Tesla S, some good info in there.


DaveMorton

A couple of things here:

1.) Battery capacity and "charge memory":

A lot of (and probably most, though almost certainly not all) types of rechargeable battery types have an issue with "charge memory", where over time, they'll only ever charge up to the level that they're charged to, if constantly not "topped off". If all you ever do is quick-charge a battery to 80% of charge, eventually, that's all you'll ever be able to charge it to. This is most common with cordless tools that have older style lithium batteries, but is still an issue with the newer versions, though to a lesser extent. From time to time, you need to completely discharge these batteries, then fully recharge them to prevent charge memory from taking hold. I'm willing to bet that this could also be an issue with the cobalt-based batteries in EV's, too.

2.) "Green" power:

While it's certainly preferable to use 100% green sources to recharge EV batteries, that's simply not possible at the moment, so it's essential to take a look at other sources for now, but it needs to be born in mind that some sources are worse for the environment than using (newer) petrol powered vehicles. Coal powered plants (and yes, my country, and more specifically, my state, are the "top sinners" here) are certainly not a viable option for EV recharging sources, but other "green" sources are also less than viable, such as hydroelectric. In the hydro example, there may not be any carbon emissions involved, but there are other ways that they damage the environment, such as water temperature increases due to friction within the turbines and other system components, AND the disruption of the natural drainage of the area in which the HE plant is location, and the disruption to and displacement of fish and other aquatic species. I could go on here, but a lecture on ecology isn't really the goal here.


@Data: I agree that a big part of the "fight" here is in educating people about options and consequences with regard to using EV more (as well as those of NOT using them), and the effect on not only the environment, but also the economy, and our culture.

re: charging cords across pavement - What if there was tech made available to provide inductive charging, just like those for Wii controllers, or some smart phones? Then the charger could be put WITHIN the pavement, and no wires or cables at all. :D
Safe, Reliable Insanity, Since 1961!

Snowcrash

I thought the memory issue with batteries was for NiCad batteries and was due to crystal build up within the battery.

As far as I know, Lithium (ion, polymer) does not suffer with this but the capacity of a 3-5 year old battery is about 50%. I think this is due to fracturing of the compounds. With a decent recycling regime at least all the compound would be reused. Lithium being more readily available (South American countries would be economic winners) than Cobolt and any other weird and wonderful elements.

Parking is also an issue (pro) as the charging point gives free parking. But I only know of 2 bays near Brighton Town Hall and 2 more up near me (Withdean Stadium) next to the Park & Ride terminal. There maybe others.

Just checked. There are 4 more, 2 by the Pier, 2 by the Level. 8 in total.
"I cannot remember the books I've read any more than the meals I have eaten; even so, they have made me."

Ralph Waldo Emerson

Carl2

Since I worked in electronics on a project that used NiCad batteries to power an electric motor, and the batteries were charged at a very high rate I'm familiar with some of the problems. The manufacture of the batteries also supplied a " coulometer " That was to measure the current taken out of the battery and to allow that current to be put back in quickly giving a full charge.  The battery is made up of 10 cells each providing 1.2 volts making a total of 12 v to power the motor.  When first made each cell is to be equal to the other cells but with wear through continued use and aging the weakest cell continues to get weaker.  The final result is after a new recharge we have 12 v but when we use the battery the weakest cell has lost it's ability to supply current, and the battery voltage drops, with continued usage the cell begins to charge negatively.  This is the memory effect that is mentioned.   The lead acid battery used in cars consist of 6 cells of 2v each will also display this memory effect and is usually called to as a dead cell.
One of the worst things you can do if a car won't start is continue turning the key until the motor no longer turns.
I don't subscribe to discharging the battery fully, it's best to find that weak cell and charge it individually. In reality you should replace the battery.
  Sorry for the length but I've just scratched the surface.  Guess well have to wait 7 to 10 years to see how the electric cars make out.
Carl2