Posted by Max Dunn
Tue, 13 May 2008 02:01:13 GMT | no comments
The electricity to power an electric vehicle costs very little – usually around 3c per mile. A bigger cost is the wear-and-tear on the batteries, which will cost 8c a mile or more.
For instance, if an electric car has a range of 75 miles with a 25kWh lithium-ion battery pack that has a life of 2,000 cycles, then the car could go 150,000 miles on the battery pack. If the batteries cost $25,000, this adds about 17c per mile to the cost of operating the car in addition to the electricity.
But what if the batteries lasted longer – much longer? Then the total cost per mile would be a lot lower.
For instance, lets say that instead of 2,000 cycles you could get 25,000 cycles out of the batteries. Maybe these batteries cost twice as much, but this would still bring the cost per mile down to about 3c per mile.
Well it appears that Altairnano might have done this. In their recently released 2007 annual report, it states that in January 2007 they completed 25,000 deep charge/discharge cycles of their batteries and they still retained over 80% of their original charge capacity.
The batteries are not cheap – it appears they are selling them for about $2,000 per kWh, about twice what other lithium-ion batteries sell for. But if they can really go 25,000 cycles in the field, it will be an exciting breakthrough!
Posted in Electric Vehicles
Posted by Max Dunn
Mon, 12 May 2008 16:04:32 GMT | no comments
Here is another illustration of how expensive hydrogen is. Popular Mechanics looked at how much it would cost to drive across the country in vehicles using different types of fuel. As a baseline, a car getting 33 MPG would cost $213 (with fuel at $2.34/gallon). A hydrogen fuel-cell vehicle would cost $804, while a battery electric vehicle would cost only $60!
Popular Mechanics: Fuel of the Future
Posted in Electric Vehicles, Sustainable Energy
Posted by Max Dunn
Fri, 25 Apr 2008 15:47:47 GMT | no comments
RAV4-EV owners have a very high level of satisfaction with their electric cars. In particular, they pleased that their RAV4-EV NiMH batteries are still going strong past 100,000 miles and are only showing signs of slowing down when they start approaching 150,000 miles. As Avi Shai reported on the RAV4-EV mailing list:
Mine is at 146,037 miles. It sure is showing signs of advanced age.
The maximum SOC I see, after full charging, is around 92%. The volt meter movement is almost directly coupled to the accelerator paddle. Even moderate acceleration causes the needle to deep precipitously close to the yellow range. Going uphill is a risky business and I try to stay in the right lane and go slow (60-65 mph) otherwise I get a visit from the turtle.
The car still fatefully does the job it was intended to, and it takes me through my 90+ miles daily commute with no problem (charging at both ends).
So even though Avi’s batteries are definitely worn down, they still get him to work and back, which is a commute of over 90 miles. And this is on battery technology that is over 10 years old. With real-world experience like this, who can still say that battery technology isn’t ready yet to support electric vehicles?
Posted in Electric Vehicles
Posted by Max Dunn
Wed, 23 Apr 2008 15:36:00 GMT | no comments
Last night, NOVA broadcast an interesting and informative show about cars of the future. It includes segments on ethanol, biofuels, hydrogen, plug-in bybrids and electric cars. You can watch it online at:
NOVA – Car of the Future
Posted in Electric Vehicles
Posted by Max Dunn
Sat, 12 Apr 2008 20:33:12 GMT | 1 comment
A new $3.2 million hydrogen fueling station opened in Sacramento last week that has 80kW of solar PV panels are used to produce the hydrogen, so it won’t use any outside energy. Let’s take a look at how efficient this is:
SOLAR OUTPUT:
- 80 kW * 5hrs = 400 kWh per day
WITH FUEL CELL CARS:
- 400 kWh / 65 kWh per kG (Stuart Energy) = ~6 kG per day (AT 5000 PSI)
- 6 kG * 45 miles per kG = 270 miles per day
- 100,000 miles per year
WITH ELECTRIC CARS :
- 400 KWH * 3 miles per kWh (RAV4 EV) = 1200 EV miles per day
- 438,000 miles per year
Considering the solar array probably cost probably cost around $10/watt, or $800,000 out of $3,200,000, the hydrogen “refueling station” cost approximately $2,400,000.
If that money had been used to build $2,400,000 of solar installation plus $800,000 of EV chargers – about 240 kW of solar and 160 EV charger stations – enough for well over a million miles per year (80 cars worth) instead of just a hundred thousand hydrogen fuel-cell vehicle miles (8 cars worth). So the hydrogen fueling station is only 10% as efficient as building solar recharging stations for battery electric vehicles.
(From RAV4-EV Digest, Vol 58, Issue 12, comment by William Korthof of EESolar)
Posted in Electric Vehicles, Sustainable Energy
Posted by Max Dunn
Wed, 12 Mar 2008 00:23:10 GMT | 1 comment
I have put over 1,000 miles on my Zapino since we got it last August, and I was wondering if I needed to get a battery management system (BMS) to keep the batteries going as long as possible. So today, after a pretty long ride where the indicator started to dip into the red, I took off the covers and checked the voltage.
The batteries were labelled:
Electier
Danwant Silicone Power Battery
6-DW-38Ah (12V38Ah)
Before charging, the voltage on all 5 batteries was between 12.58V and 12.61V. During charging, it was from 14.5V to 14.9V. Then about 30 minutes after charging was done, they were between 13.52 and 13.54V. This is very close and within specs, so it looks like the batteries are doing fine and don’t need a BMS, at least for now.
Posted in Electric Vehicles
Posted by Max Dunn
Sat, 08 Mar 2008 00:33:21 GMT | 7 comments
I was trying to explain to my wife how an air car worked, and with a smile on her face she said “So it farts as it moves forward?” Well maybe that sums it up nicely.
But do air cars really make sense? The information from the manufacturers seem like they are the solution to our energy crisis, and to everything else too [1]. But there are several fundamental problems with air cars.
Read more...
Posted in Electric Vehicles
Posted by Max Dunn
Fri, 29 Feb 2008 04:46:08 GMT | 9 comments
When companies talk about electric vehicles costing pennies per mile in electricity costs to operate, they are being truthful. However, with current battery costs and lifetimes, the battery replacement cost in an electric vehicle will be more than the electricity cost. Let’s look more closely at this.
Read more...
Posted in Electric Vehicles
Posted by Max Dunn
Thu, 28 Feb 2008 19:21:48 GMT | 3 comments
After my stop yesterday by the policeman who thought my electric Zapino scooter was a motorcycle and I shouldn’t be riding in the bike lane, I decided to try to find out more information about what California Motor Vehicle law says about this. I found this interesting “Motorized Bicycle Instruction/Application” from the DMV site that defines a “motorized bicycle” (also commonly known as a “moped”):
- Having two or three wheels
- Fully operative pedals or powered solely by electric power
- Maximum speed of 30 MPH on level ground
- Automatic transmission and a motor with less than 2 gross brake horsepower
The first two requirements are easily met, and for the third, Zap states that it can only go 30 MPH, but the Zapino actually can go a bit faster. Regarding the fourth point it does have an automatic transmission but the 3000 watt Zapino motor puts out about 4 HP, which exceeds the maximum 2 HP allowed for a motorized bicycle.
Based on this, the Zapino is close to being a motorized bicycle, but not quite since it has more power than is allowed. However, since most people want know the conversion between watts and HP, it is not obvious whether the Zapino is a motorized bicycle or not.
Posted in Electric Vehicles
Posted by Max Dunn
Thu, 28 Feb 2008 18:42:50 GMT | 8 comments
A cop just pulled me over on my scooter. I was riding in the bike line – like usual – and there was a bicyclist in the lane so I swerved around him. The cop saw this and said that since I was riding a motorcycle, I shouldn’t be in the bike lane. I explained that the manufacturer stated that it was a moped since it couldn’t go more than 30 MPH and it was all electric and so I should be riding in the bike lane. He said that I was probably going about 35 or 40 MPH (which is probably true) and that I should be riding just outside of the bike lane. However, he seemed a little unsure once I explained that the scooter was electric, so just gave me a warning.
However, this brings up a good question: should electric scooters ride in the bike lane or just outside of it? What is the maximum speed that we should go in the bike lane? In the California Motorcycle Handbook 2007 it says on Page 3:
You may ride a moped in a bicycle lane at a reasonable speed.
So is 30 MPH a “reasonable” speed to ride in the bike lane, or is this too fast?
Posted in Electric Vehicles