Eschew Obfuscation: Category Electric Vehicles

CARB ZEV Standard to be Raised

Max Dunn — Tue, 22 Jul 2008 11:24:00 -0700

Many of us EV advocates were disappointed by the ZEV mandate revisions that CARB enacted this year. So we are glad to hear that at the Plug-in 2008 conference today, CARB board member Dan Sperling said that he agreed that the revisions this year were too complex and too soft and next year they expect to simplify them and also increase the number of vehicles required – possibly by an order of magnitude. Wouldn’t that be great!

Why Can't Hobbyists Buy A123 Batteries

Max Dunn — Tue, 22 Jul 2008 10:49:00 -0700

Another interesting tidbit of information that I got from Elizabeth from A123 Systems at the Plug-in 2008 conference was why A123 doesn’t sell batteries to hobbyists for use in electric vehicles. Her answer: liability.

A123 is worried that someone will put together an unsafe vehicle and then A123 would be sued when it catches on fire or someone gets hurt. This extends also to organizations like CalCars that is working on plug-in hybrids. So A123 only supplies batteries to OEMs and manufacturers where they can be sure the batteries will be used in a safe way.

Why PHEV Engines Always Turn On

Max Dunn — Tue, 22 Jul 2008 10:40:00 -0700

One downside to current plug-in hybrid electric vehicles (PHEV) is that the gas motor always turns on when first starting out. At the Plug-in 2008 conference I asked Elizabeth from A123/Hymotion why this was and she said that the engine needed to turn on for about 57 seconds when first starting out to warm up the catalytic converter, otherwise the car wouldn’t pass smog tests. It is too bad that on short trips the gas engine still needs to turn on, but at less than a minute this shouldn’t waste too much gas.

EEStor UltraCaps - Too Good To Be True?

Max Dunn — Wed, 09 Jul 2008 15:56:00 -0700

If EEStor can achieve what they claim, it will blow open the electric vehicle market which is currently held back only by battery technology. Here is what they claim:

For a 52 kWh unit, an initial production price of $3,200, falling to $2,100.
No degradation from charge/discharge cycles
4-6 minute charge time assuming sufficient cooling of the cables.

Currently, a lithium battery pack this size would cost more than $30,000, would last less than 2,000 cycles and takes at least a couple of hours to charge.

However, EEStor is a private company and is not releasing much information to be able to verify their claims. Let’s hope that they are successful!

(Ref: http://en.wikipedia.org/wiki/EEStor)

eVolvo - Electron Hog

Max Dunn — Mon, 23 Jun 2008 11:30:00 -0700

You have heard of a “gas hog”? Well my eVolvo is an electron hog!

Most electric cars get between 2 and 4 miles per kWh. The ones that are light and streamlined and have efficient AC motors with regenerative breaking get the best mileage – and my car is none of these. It is a heavy car with a big DC motor and no regenerative braking. It does have a lot of zip, but at the cost of poor electron mileage.

Battery to wheel, I get about 2.5 miles per kWh. This is based on my maximum range so far of 25 miles, the battery pack of 15 kWh maximum, and a Peukert effect that reduces the useable energy from the lead-acid AGM batteries to about 10 kWh.

However, the Soneil 1206S chargers that are being used are not very efficient, probably around 75%. That combined with charging efficiency of the batteries which is probably around 85% gives a charging efficiency of only about 64%. So from the wall to the wheels I am getting about 1.6 miles per kWh. This figure is consistent with the data I have been collecting:

Miles	kWh	Charge Time	Miles/kWh
22.2	14	–	1.6
6.6	4.3	–	1.5
4.6	3.4	6 hrs	1.4
13.3	8.4	17 hrs	1.6
18.3	11.9	–	1.5

eVolvo Specs

Max Dunn — Fri, 20 Jun 2008 06:49:00 -0700

For those of you wondering what is in my eVolvo, here are the specs:

Batteries: Deka AGM 8A31DT 105AH @ C/20. 144 volts: 4 batteries in front, 8 in back
DC-DC converter 55 amp: IOTA DLS-55
Auxiliary battery: Deka Gel 8GU1H 32AH
Charger: 12 – Soneil 1206S 3amp (one on each battery)
Motor: Advanced FB-4001a (19 HP continuous, 85 HP peak)
Controller: Auburn Scientific PWC600-144 Kodiak water cooled
Brake vacuum: Thomas 107CDC208
Belt: A/C, Steering, Alternator

25 Watt Fuel Cell - Only $5,000

Max Dunn — Wed, 11 Jun 2008 19:26:00 -0700

With all this talk about fuel cells, I have been wondering if it is possible to actually buy one. Here is one I stumbled across a reformed methanol fuel cell that puts out 25 watts. With the standard 12 oz cartridge of methanol, it will produce power for about 7 hours. One drawback is that it takes between 12 and 30 minutes to start-up, not very convenient if you need to get someplace quick. However the real kicker is the price – $5,000! If you wanted enough of these to power a car which takes about 15,000 watts, it would cost over $3 million! Or course this is a methane fuel cell and not a hydrogen one, but it provides another reason to believe that fuel cells are not the answer to the future of transportation.

Book Review - Zoom, The Global Race to Fuel the Car of the Future

Max Dunn — Fri, 06 Jun 2008 19:03:00 -0700

ZOOM: The Global Race to Fuel the Car of the Future
by Vijay Vaitheeswaran

I wanted to like this book – I really did. With a name like "Zoom" and the promise to show the car of the future, I was excited to read it. But in the end, the book turned out to be at best a dud, and at worst misleading and harmful to the future of transportation.

Easy CO2 Calculation for Vehicles

Max Dunn — Fri, 06 Jun 2008 17:05:00 -0700

Sometimes you will hear that electric vehicles produce more CO2 than gas vehicles, however, this isn’t true. Let’s look at an easy CO2 calculation to see why.

Burning a gallon of gas creates 20 lbs of CO2. So a car that gets an average of 20 MPG produces 1 lb of CO2 per mile. Ok so far?

Electric cars get an average of 3 miles per kWh and 1 kWh creates an average of 1.3 lbs of CO2. So an electric car produces about 0.4 lbs of CO2 per mile. So electric cars produce only about 40% as much CO2 as gas cars. Easy, right?

eVolvo - My Electric Car

Max Dunn — Wed, 04 Jun 2008 14:04:00 -0700

I finally did it – I got an electric car!

We had been considering a Miles NEV, but were concerned that even after tweaking it to go 35 MPH (rather than the 25 MPH it is supposed to go) that we would still get run over when driving on streets where the speed limit was 40 MPH or higher. The Miles also would have cost close to $20,000, and even then it was pretty minimal – vinyl seats, manual crank windows and no air-conditioning. So when a converted 1995 Volvo 850 came up for sale nearby for $14,000 we jumped on it!

Powering Electric Vehicles

Max Dunn — Mon, 02 Jun 2008 08:34:00 -0700

One question that is often asked is that if we start to have a lot of electric vehicles, won’t this strain our electric system and require us to build a lot of new electric power plants?

The answer is no – at least at first. The reason is that electric usage goes down considerably at night. By simply charging at off-peak times, then we can use electricity from the plants that would have otherwise been idle.

Let’s look at the math. An electric vehicle consumes 1 kWh from the wall socket for every 2-4 miles driven. The average car is driven about 30 miles per day – so the average daily energy needed per car is only 10 kWh. If these vehicles are charged over 10 off-peak hours, the average power consumption per car is 1 kW. Since California has 25 GW of spare off-peak electric capacity, this can power 25 million electric cars in California alone.

This is just a rough calculation, but the same conclusion was reached in a detailed analysis which found that 84% of all cars in the US could be powered by the existing electricity infrastructure.

Gas vs Electric Motor

Max Dunn — Sat, 31 May 2008 16:27:00 -0700

Which do you think provides more performance by weight and size – a gas motor or an electric motor?

You are right if you said an electric motor. Here is a picture of an electric motor that provides twice the performance of the gas motor, yet is much smaller and has only 1 moving part!

(Reference: EVDrive BMW Project)

Clouds and Gusts = Regulation Problems

Max Dunn — Wed, 28 May 2008 12:26:00 -0700

All of the major electricity generating systems in use today have a fairly steady output. Whether they are powered by nuclear, coal, hydro or natural gas, the electricity output will be fairly constant unless there is a malfunction. However, solar and wind systems aren’t consistent – clouds can dramatically affect the output of solar systems, and lulls and gusts can affect wind systems.

In our electrical grid, it is important that the supply of electricity consistently matches its demand. This will become more challenging once solar and wind systems are producing a larger percentage of the total electrical power, and there are currently no good ways to smooth out these fast fluctuations. Spreading the solar and wind units far apart helps so that clouds and gusts won’t affect all the units at the same time. Also pumped hydro (where water can be pumped up into a dam using electricity as well as letting it out to produce electricity) can help smooth things out as well as using natural gas spinning reserves.

However, we will still need more regulation that is much faster than these, and this is where Vehicle-to-Grid can help. If we can reach a level where a significant amount of electric vehicles are hooked up to the grid with fast command communication, they will be able to quickly smooth out the electrical surges and lulls from solar and wind systems. Otherwise, we will likely run into severe regulations problems with these systems due to clouds and gusts.

RAV4-EV Sold for $70,000

Max Dunn — Wed, 28 May 2008 08:33:00 -0700

There certainly a lot of excitement over electric cars these days. A 2001 Toyota RAV4-EV with over 47,000 miles sold on eBay for almost $70,000! (The selling price listed was $89,000 but this was an illegally retracted bid and the seller confirmed that it was sold for $69,850.)

It was in good shape with only minor scuffing on the left bumper and had an HOV stickers so it can drive in the car pool lane, but $70k seems like a lot of money for an electric car with almost 50,000 miles. Hopefully next year we will start seeing brand new electric cars closer to $40,000.

If you still are dying to get one, there is another RAV4-EV for sale on eBay and the bidding is currently at $50,000.

AGM Battery Charging - Temperature Dependent

Max Dunn — Fri, 23 May 2008 19:00:00 -0700

As we have seem, the biggest per mile cost of running an electric vehicle is not the electricity, it is the battery depletion. So it is important to maximize the life of your batteries. One trick that works with all battery techologies is to take short trips and recharge after each one. By minimizing your depth of discharge (DOD) you will maximize the total energy that the batteries will deliver over their life.

Another very important factor is to charge the batteries correctly. Especially for sealed lead-acid batteries like gel or AGM, correct charging is critical. Deka states that if their batteries are continuously charged with a voltage that is only 0.70 volts over the proper charging voltage, it will reduce the battery life by 60 percent! This is because if sealed batteries are overcharged, they will dry out and there is no way to replace the lost moisture. It is likely that all sealed lead-acid batteries will suffer from this, not just Deka batteries.

Here is the kicker: the proper charging voltage varies depending on the temperature. It ranges from 15.10 volts when it is below 40 degrees 13.60 volts when it is above 120 degrees. And it is not good enough to just measure the air temperature, instead it is important to measure the temperature of each battery since they will often be warmer than the outside air.

So unless your charger or BMS has a temperature probe on each battery, it is almost guaranteed that the batteries are not being charged correctly and that their potential life span will be reduced.

Ford EV Ranger Cost Analysis

Max Dunn — Wed, 21 May 2008 11:19:00 -0700

BlueSky Motors in Sacramento periodically sells EV Ford Rangers on eBay.

When I contacted them about the reserve price for a previous EV Ranger, here is what they said:

The reserve on the vehicle is $26,998 + License, Calif. sales tax, doc fee, and registration. The total cost with a PSC charger ($600.00) ends up close to $29,000. You can call for a test drive – (916) 929-7508 ask for Scott.

Paying almost $30,000 for a Ford Ranger seems pretty expensive – is there a way to justify this? One way is to think about the extra cost as just “pre-paying” for your gas.

The gas 1999 Ford Ranger gets a combined mileage of 16 MPG, so this is about $0.25 per mile at $4 per gallon. Assuming electricity will cost $0.05 per mile, you will save $0.20 per mile with the EV Ranger. (The EV Rangers NiMH batteries will likely last for the life of the car, or about 150,000 miles, so you don’t need to worry about battery replacement costs.)

So one way of looking at the extra $20,000 that this EV Ford Ranger costs is that you are just pre-paying for gasoline at $4 per gallon for the next 100,000 miles and after that, it is like getting free gas. And when gas goes up to $6 a gallon or more, this will seem like a real bargain!

Hill Climbing in EVs

Max Dunn — Mon, 19 May 2008 08:42:00 -0700

When driving an electric vehicle (EV), it is important to know how far you can go on a full charge. On flat ground, the range will be pretty consistent and the only variable will be if you are driving around town or on the freeway. But how will your range be affected when you are driving up a hill?

This is an important question to me because I like to go surfing in Santa Cruz which is about 30 miles away and requires a climb of 1500 feet over a mountain range.

As a rule of thumb, you can add 10 miles for every 1000 feet you climb. So to take the Santa Cruz example, the peak is 15 miles away and a climb of 1500 feet, so it would actually take 30 miles of energy to get to the peak.

Going downhill of course, won’t take as much energy and will actually add some energy if you have regenerative braking. So the total trip to Santa Cruz is likely to take about 37 miles worth of energy.

RAV4 owners have reported that it takes less energy to climb a hill, only 6 miles per 1000 feet. One owner reported driving to Mt. Baldy which was 20 miles away and a climb of 6000 feet. He used about 60 miles worth of charge to get to the top. However, coming back down he added 20 miles of charge, so the round trip only took 40 miles of charge, or only the linear distance disregarding the climb. Ref

Bottom line is that while you need to be aware that it takes extra energy to climb hills, EVs can handle them with no problem.

Zapino Batteries Weakening

Max Dunn — Wed, 14 May 2008 11:10:00 -0700

While Altairno batteries have demonstrated 25,000 cycles, my Zapino batteries are starting to weaken after less than 500 shallow cycles.

This was evident in a ride I took today to Los Gatos to get a new battery for my MacBook. (Yes, even the lithium-ion battery in my MacBook gave out after less than 300 cycles! But this was likely just a manufacturing problem, not an inherent limitation.)

I knew the Electier batteries in my Zapino batteries were getting weak, so I rode in the “economy” mode the whole way, accelerated slowly and rode 25 MPH or less. There were some small hills but I took it really easy going up them. Nonetheless, by the time I was approaching home, the needle was dipping into the yellow upon acceleration and even starting to get in the red. The entire ride was 14 miles, and I probably could have nursed it another 3 to 5 miles, but this was still only about half of the 30 mile range that we got when the Zapino was new.

Altairnano Batteries - 25,000 Cycles

Max Dunn — Mon, 12 May 2008 18:45:00 -0700

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!

Hydrogen 13 Times More Expensive Than Electricity

Max Dunn — Mon, 12 May 2008 08:59:00 -0700

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

RAV4-EV 146,000 Miles and Still Going

Max Dunn — Fri, 25 Apr 2008 08:33:00 -0700

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?

NOVA Car of the Future

Max Dunn — Wed, 23 Apr 2008 08:29:00 -0700

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

Hydrogen Fueling Station: 10 Times Less Efficient

Max Dunn — Sat, 12 Apr 2008 13:21:00 -0700

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)

Zapino Battery Report - 1000 miles

Max Dunn — Tue, 11 Mar 2008 16:18:00 -0800

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.

Farting Along With Air Cars

Max Dunn — Fri, 07 Mar 2008 16:32:00 -0800

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.

Electric Vehicle Battery Costs Per Mile

Max Dunn — Thu, 28 Feb 2008 20:44:00 -0800

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.

What is a "Moped"?

Max Dunn — Thu, 28 Feb 2008 20:07:00 -0800

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.

Scooters in the Bike Lane?

Max Dunn — Thu, 28 Feb 2008 10:36:00 -0800

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?

Bike Riding for Errands

Max Dunn — Tue, 12 Feb 2008 12:30:00 -0800

I should ride my bike more. It is good exercise and saves the environment. However, I don’t like to ride my bike on everyday errands.

I was reminded of this today when I got new tires for our car. Like usual, I threw my bike in the back and rode home after dropping off the car. It isn’t far, about 2.5 miles, but I was hot and sweaty when I got home. I was smart this time and brought a piece of string to wrap around my pant leg. Usually I forget this and wind up getting chain oil on my pant leg.

When the car was ready, I rode back to the shop to pick it up, and I was a bit tired.

So it certainly worked out fine to ride my bike, but it isn’t something that I would normally do. Also, for the same reasons, I don’t think we can expect many Americans to forgo their cars and start doing a lot more bike riding either. Good thing I have my electric scooter to scoot around on!

Hydrogen Powered Vehicles are Not Viable

Max Dunn — Tue, 05 Feb 2008 17:46:00 -0800

Regardless of what Bush thinks, hydrogen powered vehicles are not a viable alternative.

First off, hydrogen is not something that can be “mined”, but instead must be produced using other energy sources [1]. With current technologies, electricity from hydrogen fuel cells is four times more expensive than electricity from the grid [2]. Secondly, hydrogen is very difficult to ship and store. Leave a hydrogen car at the airport for two weeks and half of the fuel will be lost due to evaporation [2]. Thirdly, while hydrogen fuel cells are clean, currently hydrogen fuel cells are costly to produce and fragile [3] and only about 50% efficient [4]. Lastly, hydrogen is not very dense so cars would need to have a tank 2-3 times larger than their gasoline tanks [3].

With all things considered, it doesn’t make sense to power cars with hydrogen; instead, just put batteries in the car and use the electricity directly.

References:

Battery Electric Vehicle User Experiences

Max Dunn — Mon, 04 Feb 2008 10:10:00 -0800

Ron Freund, past Chairman of the Electric Auto Association, took a survey of 116 RAV4 -EV owners to see how they liked driving a battery electric vehicle (BEV) in general, and in specific, how their experience with the RAV4-EV has been. This is a great reference for anyone interested in how a BEV performs in the real-world. Some of his conclusions are:

Users frequently commented that the RAV4 has been the best car they ever owned
The RAV4-EV dependability is remarkable
The technology is working, no more research is needed
It is a tragedy that the choice for BEVs does not exist in the market today

Living with a BEV: A Survey of User Experiences

Vehicle-to-Grid (V2G)

Max Dunn — Wed, 30 Jan 2008 16:20:00 -0800

What is with this vehicle-to-grid (V2G) stuff? Why is everyone so excited about it? I already showed how using batteries to store energy at night when it is cheap and then use it during the day doesn’t make sense economically¹.

However, this is only part of the picture. It turns out that electricity generation is very complicated, in large part because there is no real storage on the electrical grid. Think about this: what happens when the power plants on the grid don’t produce enough electricity? There will be brownouts or blackouts, both of which are bad. But what happens when they produce too much electricity? Where does it go? Well, actually, since there is no real storage on the grid, it can’t go anywhere, so this is bad.

Which Alternate Energy Vehicle is the Most Efficient?

Max Dunn — Thu, 24 Jan 2008 17:33:00 -0800

There are several better energy alternatives to power cars than using gas. The top ones are hydrogen, air or battery. However, it turns out that there are big differences in the efficiencies of these technologies. For 100MJ of input electricity, this is how far each of these cars could go: [18]

133 km: Lithium-ion battery vehicle
46 km: Compressed air car
42 km: Fuel cell vehicle

So it turns out that battery electric vehicles are 3 times more efficient than either compressed air or fuel cell vehicles!

Strangely, Power Company Rebates Make Sense

Max Dunn — Tue, 22 Jan 2008 17:17:00 -0800

It seems awfully strange that a company that sells power would subsidize compact fluorescent lights (CFLs) that use less energy, and give rebates for energy efficient appliances. This would be like Starbucks giving awards to people who cut down on their coffee drinking! But even though this seems strange, power companies trying to cut power consumption actually makes sense.

The Trouble with Lithium

Max Dunn — Wed, 09 Jan 2008 11:39:00 -0800

It turns out that lithium is not very abundant or easy to mine, and that the price is going up. In this paper, the author even argues that there is not enough lithium available in the world to convert all cars over to plug-in hybrid (PHEV) if we expect to use lithium batteries in them:

The Trouble with Lithium – Implications of Future PHEV Production for Lithium Demand

Lithium Silicon Nanowire Battery - 10 Times As Much Energy!

Max Dunn — Wed, 09 Jan 2008 10:16:00 -0800

An revolutionary new technology is being developed by Stanford researcher Yi Cui that could could generate 10 times more energy from lithium-ion batteries. The trick is that instead of using carbon anodes, they use silicon nanowires because silicon can hold large amounts of lithium atoms. The nanowire technology allows these small wires to swell to four times their normal size without breaking. [1]

When Cui’s paper was originally submitted six months ago, they had only achieved 30 charge-discharge cycles. Since that time however, Cui’s team has pushed the battery through 1000 cycles. [2]

Ultimately, these batteries should be cheap to build. However, they are probably 5 years away from being commercialized. [3]

In reality though, the “10 times more energy” figure is just the theoretical charge capacity increase in the silicon anode, so a real production battery won’t see that much improvement. But even if it improves the overall energy density of a lithium ion battery by 2 or 3 times, that would still be very significant.

[1] Nanowire battery can hold 10 times the charge of existing lithium-ion battery

[2] New Nanowire Battery Life Reaches From iPods to Electric Cars

[3] GM-Volt.com: Interview with Dr. Cui, Inventor of Silicon Nanowire Lithium-ion Battery Breakthrough

Electric Vehicles Produce a Lot Less CO2

Max Dunn — Sun, 30 Dec 2007 09:35:00 -0800

When I talk about how clean electric vehicles are, people sometimes ask if they really do reduce greenhouse gases since burning coal to produce electricity creates a lot of CO2. My standard answer to this question is that even in the worst case, electric cars are twice as clean as gas powered cars. However, while reading an article in Forbes about vehicle-to-grid (V2G) systems. I realized that in general, electric cars are much cleaner than even this.

This article had an interesting chart that said electric cars produce about 1.1 tons of greenhouse gases a year while gas powered cars produce 6.3 tons – over 6 times more! Let’s see if we can verify these numbers.

The average car is driven 15,000 miles per year and electric vehicles normally get 4 miles per kWh, so it takes about 3,750 kWh of electricity a year to power an electric car. In California, the mix of electricity production produces about 0.6 lbs of greenhouse gases per kWh so this would produce 2,250 pounds, or 1.1 tons of greenhouse gases – right on the money with the Forbes chart.

A gas car, on the other hand, produces about 1 lb of CO2 for every mile driven (based on producing 20 lbs per gallon and getting 20 mpg). So 15,000 miles would produce 15,000 lbs of greenhouse gases, or about 7.5 tons – which is more than the Forbes estimate of 6.3 tons (maybe they are using a higher mpg).

So electric cars are even cleaner than I had thought, producing about one sixth as much greenhouse gases as a gas car.

When to Buy an Electric Car?

Max Dunn — Tue, 04 Dec 2007 09:09:00 -0800

That is the question – whether to buy a low-speed electric vehicle now, or wait for a high-speed electric vehicle later? Here are the factors I am looking at:

What type of transportation do I need?
When will high-speed electric vehicles really arrive?
How much will they actually cost?
When will the severe oil shortages start?
Will there be subsidies for electric vehicles?

The short answer is that I am going to buy a low-speed NEV now and wait for later to buy a freeway capable electric car. Here is the long answer:

Grocery Shopping on the Zapino

Max Dunn — Wed, 12 Sep 2007 13:26:00 -0700

Today, I went grocery shopping on our electric Zapino. I was a little worried that I wouldn’t be able to fit all the groceries in the basket and under the seat, so I took a Trader Joe’s bag too and planned to hold it between my feet. However, it turned out that I didn’t have any problems. Here is what I bought:

Large powdered Gatorade
2 – Boxes of cereal
Half gallon milk
Quart of goat’s milk
Jar of mayonnaise
2 – Tamales
Frozen fish
Asparagus
French rolls

As you can see from the pictures, they all fit in nicely! I definitely could have squeezed a few more things in, and then could have filled up the shopping bag and put it between my feet.

Zapino Charging

Max Dunn — Sun, 02 Sep 2007 08:02:00 -0700

After running the Zapino battery all the way down last night, I put the charger on it with the Kill-A-Watt meter to record how much power it would take to recharge. The charging rate started at about 360 watts and then increased to 400 watts. The total power consumed was 2.68kWh.

This is an interesting number and does make sense since the battery pack is rated at 2.28kWh (60v-38ah) and you would expect that there are some losses when charging. Sealed lead-acid batteries typically can be up to 95% efficient and chargers are typically 90% efficient, so combined these numbers lead to the total efficiency we measured of 85%.

Another useful fact about charging is that for every hour that the scooter is being charged, you are adding about 4 miles to the range. (Based on the charger putting out 400 watts, and the Zapino using about 100 wh/mile.) So, for instance, my wife works part time at an office about 18 miles away. So if she is there for 4 1/2 hours, the Zapino will be completely recharged.

Zapino Range

Max Dunn — Sat, 01 Sep 2007 19:01:00 -0700

After the excursion with my wife today where we traveled about 20 miles, I went to go pickup my son at the pool which was a little over 5 miles away. I was still taking it easy in economy mode and staying around 25 mph. However, I did go through the neighborhood where there were a lot of stop signs. Coming back home, we got about 3 miles away and the range indicator starting to drop into the yellow when we accelerated. At 2 miles it was dropping into the red, so I started driving 15-20 mph. At about 1 mile away, the engine cut out because the indicator dropped below the road while accelerating. Coasting to a stop, I turned off the key and back on again and was able to continue. I then starting going really slowly, about 10 mph. The engine cut out a few more times, but we made it home. So i consider that we fully utilized all the available range.

Total distance today 31.2 miles. Not bad!

Zapino Excursion

Max Dunn — Sat, 01 Sep 2007 17:02:00 -0700

Last Wednesday, after weeks of looking around at electric scooters, we finally bought a Zapino and love it! Today, Suzanne and I took a little excursion around town to see if it could carry both of us and to see how the battery would hold up on a longer trip.

The first thing you should know is that it was hot in San Jose today, getting up to 94 degrees. Riding the Zapino was nice because the breeze cooled us off. However, we were worried that it would overheat because we were pushing its 282 lb weight limit with our combined weight of 275lbs. (And no, Suzanne forbids me to break out our weights separately. ;-)

Since we were just out cruising, we were using the energy saving mode which limits the top speed to 30mph. Most of the time, this is plenty fast, but I did kick it into high-speed mode several times going down Highway 9 to Los Gatos.

The Diagnosis light was flashing its 2-3 combination which means that it is overheating, but I just ignored it and kept going

We stopped at a store and looked around for about 5 minutes. When we got back on the Zapino, the overheat protection kicked in and it made us go really slow. This was probably because after stopping, there was no more wind to cool off the controller and it was so hot out anyways. This slow speed was fine since we only needed to ride a block. We then got off again and walked around for about 20 minutes before getting back on the scooter, at which time it had cooled down.

Going home, we continued to take it easy but the “overheating” warning starting flashing again very soon. This didn’t seem to make any difference, although our top speed was a little lower, around 25 mph in the energy saving mode. Just for fun, right before we got home I put it back into high-speed mode and it sped right up past 30 mph, no problem.

I realized on this trip that the diagnosis light is a little annoying. In order to read the flashing codes, you have to look at it continuously for about 5 seconds, which is very dangerous while driving.

Our total outing ended being about 20 miles and the charge indicator was only about halfway down in the green. So we have now confirmed that driving conservatively with a heavily loaded bike can take you at least 20 miles on the Zapino.

Suzanne and I really enjoyed our little excursion on the the Zapino!