Nissan Leaf vs. Chevy S10 pickup

A few years ago, my sister was getting rid of her Geo Metro so I bought it off of her for $1.   

I had great plans to convert it to an all electric car. I only needed a 30 mile max range for my commute to work and back. The Geo was the ideal car for converting to EV. It was light weight and had good handling.  People have used them for years as a donor car for electric cars.

I stripped out the engine and acquired most the parts I needed,  One day, we decided to move to a larger house. Sadly I had to admit defeat when the house we moved in to was out of the range of the electric car's design. I chocked it up to a learning experience and sold the parts, liquefying my asset.

To this day, I still consider this poor excuse for an excuse my greatest failure. I vow that my next vehicle will be an all electric car.

I have been thinking about two options: The Nissan Leaf or converting a Chevy S10 pickup truck to an electric vehicle.  

Let's list the pros and cons: 

• The Nissan Leaf is very expensive but super cool. The Chevy S10 EV will be about 1/3^rd the cost and also super cool.
• The Nissan Leaf is a new car filled with the latest technological gadgets.
• The Chevy S10 pickup EV will be very basic and plain. I've never had such fancy stuff in a car so why start now?
• The Leaf has a 100 mile range. The S10 EV will be lucky to get 60 miles. My commute is only 20 miles each way.
• The S10 being a pickup truck will be able to haul lumber, sheet-rock, dirt and bags of concrete mix.
• My current vehicle (1992 Honda Accord) has been my reliable “work truck” and has served me well in hauling everything except for Sheetrock. The Leaf would be too expensive to use in this manner.
• The S10 would be a total blast to strip down and convert over to an electric car.   I need me a new hobby!  The Leaf, well....  Not much to do on it.  Drive it home and then what? 
• The Leaf will cost me almost $31,000 where as the S10 will set me back $11,600. I could buy a lot of whatever with the $18,900 saved in rolling my own instead of buying a bran new car.  

Nissan Leaf (100 miles)         Chevy S-10 (60 mile range) 
Car                      $33,720.00   Minor repair work                 $250.00

Charging station    $2,200.00   Donor vehicle '94-98 S10   $1,750.00

Rebate                 -$7,500.00   A/C Electric Kit                  $8,115.00

Acquisition Fee        $595.00   x18 T-145 6V batteries       $3,222.00

Taxes                    $1,958.51   Miscellaneous                        $500.00

Sell Honda              -$500.00   Sell Honda                            -$500.00

                                              Tax Credit                          -$1,333.70

                                              Sell old truck parts                -$400.00

    

Net Cost Leaf    $30,473.51  Net Cost Chevy S10 EV   $11,603.30

Savings of converting vs. buying new  $18,870.21

• Which begs the question, why not drop an extra $4000 on Lithium batteries instead of lead acid ones.
• Pound for pound, lithium batteries have 3 times the capacity of lead acid. Not only would the S10 have extended range but it would also have increased weight carrying capacity. Since the batteries are the last thing I would buy when converting to an electric car, I have time to give this more thought.

The Results Are In! 
I'm going to try my hand at converting another electric car. Now I just need to find a cheap S10 with a zillion miles but a good frame, body and interior.

Lawn Mowers

I prefer electric lawn mowers to gas ones because they are super quiet, they don't pollute and I don't have to buy gas.   The only problem is corded electric models are a hassle and cordless mowers, due to limited battery capacity are only suited for small lawns.  For my ½ acre lot, neither option was acceptable. 

John's Rule #106:  If you can't find what you need, invent it!  

My lawn mower uses a 115 Amp-Hour, 12V deep cycle battery to power a 750 watt AC inverter that in turn powers a 157 VDC motor that has been connected to a bridge rectifier so it can run off of normal household AC power. Granted, it’s kind of stupid to convert DC to AC and back again to DC but that’s exactly when I have done.  The down side to my Frankenstein mower is that it's not self propelled and the deep cycle battery on board weighs a lot.
I'm still looking for the parts so I can connect a 12 volt motor to the back wheels.  In the mean time, mowing the lawn is good exercise. 
When my mower is drawing the maximum amount of power, the 12 volt battery  has to provide 62.5Amps continuously.  That gives me 1 hour 50 minutes before the battery goes totally dead.  This isn't a problem because my lawn only takes about an hour to mow and the mower doesn't always draw maximum power anyway. 

750 watts is only 1 horsepower but an electric motor is way more efficient than a gas engine. My lawn mower has the equivalent grass cutting abilities of a 3.5HP gas mower. 

This season, I have been baffled as to why it has been taking me 2 deep cycle batteries to mow my large lawn instead of only one.  Last season, I would boast that I could mow the entire lawn and only use ½ the capacity of my battery. 
Having my lawn recently aerated left thousands of little grass poops all over the lawn.  You should have seen my 2-year-old daughter, (thinking they were dog poops), try to walk across the lawn with ever-so-much care and caution. She had such a cute, disgusted and worried look on her face.

Mowing the lawn after aeration, the occasional lawn poop would hit the blade with a “twang” before being obliterated. It was fun to do but it wrecked havoc on the blade.

I sharpened my spoon sharp lawnmower blade to that of a spinning-death steak-knife.  The revived blade helped a moderate amount but my mower would still bog down in long, thick grass.  What is going on here?  
Then it occurred to me that the first time I mowed the lawn this season, I lowered the blade down to a 2" cutting height and I neglected to raise it back up to the original height of 2 ¾”. After raising the blade back up, I was able to mow the entire lawn using only one battery. 

After measuring my lawn mower's performance (with a Kill-A-Watt meter) and applying some crude calculations, I arrived at these surprising statistics: 

• A sharp lawnmower blade will use 33% less energy than a dull blade. 
• Raising up the deck only ¾", extends the range of the lawn mower by 40%. 

This is true for gas or electric lawn mowers. 

Unless you have a putting green, there is no practical reason to cut the lawn short.  I found that cutting the grass a little bit longer will in return yield several benefits:

1. A healthier lawn. 
2. The lawn remains greener with less water.   
3. Takes less time to cut. 
4. The lawn mower does a better job of cutting/mulching the grass.  
5. And amazingly, it uses less energy. 

After collecting data from a few of my neighbors about their lawn mowers, I found that a ½ acre lot can be mowed using 1 tank of gas (0.4 gallons) at a fuel cost of $1.50/week, spanning a 21 week grass mowing season.  Using these figures, my $84 battery needs to last at least 2.4 years to pay for itself.  
Well, it has already done that since I am into my 3rd year of using this battery. 

After mowing, the battery is only 45% discharged.  Conveniently, this also extends the overall life of the battery. 

The x-axis is the discharge percentage of the battery.  The y-axis is the number of charge cycles. 

Amazingly, only discharging 45% will allow a battery to last 1200 charge cycles, (1200/21 = 57 years).  Due to the cheapness of my battery, I'm conservatively estimating mine will only last for 250 charge cycles or 12 years.  We'll see. 

My ½ acre lot with ~¼ acre of lawn requires ~0.7KWH of energy from the battery and 1KWH of electricity to recharge the battery. That’s about 10 cents per week to mow my lawn.   Since solar panels provide all my electricity, my lawn mower is effectively solar powered.

Nerdy Fun Facts:

• There are 125,000 BTU in a gallon of gasoline and 3412 BTU in a KWH.  An equivalent gallon of electricity would be 36.6KWH. 
• Gasoline has an amazingly high energy density.  Storing the same amount of electrical energy (as a gallon of gas) into cheap deep cycle lead acid batteries would require 2036 lbs of batteries.  Since you can never retrieve 100% of the energy stored in a battery, you would actually need more than this. 
• A typical push mower has a 0.4 gallon gas tank.  My electric lawn mower uses 15 times less energy to mow a lawn than a gas mower. 
• The deep cycle battery on my lawn mower weighs 78 lbs but only releases the (usable) equivalent energy contained in 2¼ ounces of gas. 
• The ideal grass cutting height (in my opinion) is: 2 ¾“.  This saves the most energy but still keeps the grass relatively short and manicured. 
• You can measure your own lawn mower's cutting height by placing the lawn mower on flat cement.  Measure from the ground to the bottom of the lawn mower deck.  The cutting height will be 0" -¼" higher than this. 

Update: 
The weak link in the run-time for my lawn mower is the inverter's low voltage cutoff circuit.  Once the voltage at the inverter drops below 10.7 volts, it's game over.  After drawing 60 amps from a 12 volt battery for 50 minutes continuously, the battery voltage (while drawing a heavy load) is about 10.9 volts.  The voltage drop across the 18" cables running from the battery to the inverter is about 0.2 volts with a resistance of 0.004 ohms.  After beefing up the cables with much larger gauge wire, the voltage drop is only 0.03volts and only 0.0007 ohms. 

The small red and black cables were what was used before.  I added the larger red and blue cables.

I can always tell when my lawn mower battery is around 55% because (while pulling 60 amps), that is when my inverter starts squawking about low voltage.  Before beefing up the cables, I was never able to discharge the batteries below 50% before the inverter's low voltage circuit pulled the plug on my mowing "fun".  After I reduced the voltage drop across my cables, I can complete the entire lawn without the inverter voicing a single complaint.  This effectively bought me an extra 25 minutes of run-time.

I am toying with the idea of swapping out my 78 lb lead acid battery for a 28 lb, 100AHR LiFe battery.  But at over $500, can I justify the cost?  Dang!  Science can be expensive. 

Increase Your Gas Mileage by 41%, No! Wait!! By Over 63%

Last month I wrote an article about how you can increase your gas mileage 41%.  I'm here to report that this figure was grossly inaccurate.  The truth is, you can actually increase your gas mileage by over 63%.  I know this because I have done it, reliably.  As I learn more techniques and tips, my gas mileage just keeps getting better and better.  Achieving such dramatic efficiencies in a normal internal combustion engine does not require doing anything drastic, dangerous or illegal.  There are some people that use more"shady" techniques like drafting off of semi trucks.  While this may increase their fuel economy, it is illegal, dangerous and doesn't reduce the environmental impact of burning fossil fuels.  It merely passes the costs of fuel from the drafter to the truck driver. 
I was able to increase my performance an additional 22% (above the 41% I was already achieving) for a total of a 63% increase.  This latest 22% requires installing a tool that provides instant feedback about how driving style is effecting the fuel economy and changing your driving style to attain maximum fuel economy.  Instant feedback is the key to such dramatic fuel savings. 
One such tool is the vacuum gauge.  It will work on any vehicle, costs you less than $30 yet it will save you hundreds at the pump. 

The Vacuum Gauge that I installed in my 1992 Honda Accord displays a vacuum pressure ranging from 0 to 30 Hg (inches of Mercury).

The gauge's vacuum hose connects to the extra port on my intake manifold. How convenient that there was an extra port. No cutting or splicing involved.

Vacuum pressure at the intake manifold is loosely correlated to fuel efficiency.  The harder you push on the gas pedal, the lower the vacuum pressure and the more gas your vehicle will consume. For my car, the gauge displays 0Hg at full throttle and as high as 24Hg when it is coasting in gear.  My car gets much, much higher gas mileage when I drive in a manner that keeps the vacuum pressure as high as possible.  Typically this is in the 12-18Hg range. 
Cruising on the freeway I can maintain a vacuum pressure of 15Hg.  The vacuum gauge also doubles as an inclinometer.  Driving up a hill (like an overpass) while maintaining a constant speed, the vacuum gauge will drop down toward 10Hg.  Driving down the other side, the gauge jumps up toward 20Hg. 
By driving so that the vacuum gauge remains at a constant vacuum pressure, your speed may fluctuate, your acceleration will be smaller but your fuel efficiency will be much, much higher. 

From last week's blog post, we learned that when a vehicle is driven at a low engine RPM, fuel economy goes way up.  But pushing too hard on the gas pedal while in an upper gear will bog the engine down, potentially negating any fuel savings (automatic transmissions don't suffer from this but they don't get as good of fuel economy either). 
Fortunately, the vacuum gauge will indicate if you are bogging the engine or not.  If you are cruising along a 30mph street in 4th or 5th gear, with very little throttle, the vacuum gauge will still display a nominal value.  But even an unnoticeable increase in throttle position will bog the engine down and kill the vacuum pressure at the intake manifold, increasing fuel consumption.  Having this feedback is key to driving at the lowest possible RPM while still preventing bogging and preserving fuel efficiency. 

For vehicles newer than 1996, the superior version of the vacuum gauge is the Scan Gauge II. 
Not only does the Scan Gauge calculate and display dozens of parameters like miles per gallon, gallons per hour, total trip cost, closed loop status and engine temperatures, it can also be programed with vehicle specific gauges for your particular vehicle.  For example, for my wife's Chevy Venture, it will display horse power, engine torque, air/fuel ratio, transmission temperature and even an obscure parameter called “knock retard”, (how many degrees of ignition time advance must be removed to compensate for low octane fuel, thus preventing engine knocking).  For hybrid vehicles, the Scan Gauge will display "state of charge" and the regenerative charge rate of the battery system. 

Efficient driving habits will save you money at the pump in exchange for a slight increase in commute time. 

For me, slower acceleration and reduced cruising speed adds 3 additional minutes to my 20 mile commute.  In exchange, I only have to pay to fill up for gas tank every 4 weeks instead of every two and a half.  Not a bad compromise in my opinion.

Questions/Myths about Vehicles answered by John

Lindsey from Texas:  What is the difference between driving with low air pressure in the tires and normal pressure?  What is the ideal tire pressure? 
I ran several tests using a 2002 Chevy Venture mini-van and a Scan Gauge tool.  I lowered the tire pressure in each tire to 25psi and took several samples while driving on a flat road at 30mph.  I then pumped up each tire to 32psi and took several more measurements.  Finally, I pumped all the tires up to 42psi and drove around for several more measurements.  Here are my results: 

While driving at 30mph on a flat road. 
Tire Pressure    GPH (avg)    MPG (avg)
25psi                  1.55gph          20.0mpg
32psi                  1.23gph          23.85mpg
42psi                  0.92gph          33.08mpg

Having low tire pressure will reduce your fuel efficiency over 40%.  Keeping your tires at close to the maximum pressure written on the sidewall will give you the most fuel efficiency. 

Niko from California:  Does driving with the windows open hurt fuel efficiency? 
To my suprise, and amazingly, no!   I had to run this test over and over just to make sure.  A few of my results even show an improvement in fuel efficiency when rolling down the windows.  My "baffle you" theory is modern vehicles have a more aerodynamic shape.  This creates a bubble of air around the vehicle as it drives.  Rolling down the window does not slow the car down because the bubble preserves the aerodynamics. 

Speed       Windows up    Windows down
75mph       29.5mpg           29.8mpg
70mph       25.5mpg           24.0mpg
65mph       26.1mpg           28.1mpg
60mph       29.0mpg           32.5mpg
55mph       33.7mpg           31.5mpg

Karen from Oregon:  Is it bad to start the car with the A/C on?  Also will it hurt the car to keep the A/C on when driving up a big hill? 
Starting the car with the A/C turned on doesn't hurt it at all.  If you leave the A/C button on all the time, when you start your engine, the vehicle computer delays the A/C from turning on.  My van takes about ¼ second after the engine is turned on before it automatically engages the A/C compressor.  Cars are pretty smart.  On steep hills, when the engine is really working hard, most cars automatically turn off the A/C to save performance.  Next time you are driving up a steep hill this summer, leave the A/C on.  You may notice the air coming out of your vents won't be as cool as it should be.  This is an indication that your vehicle is switching off the A/C so all available power can be used for getting up the hill.  Or maybe it's about to blow up (j/k).  By the way, it is normal for the air conditioner compressor turns itself on and all the time.  But during the times when it is on, it only uses 3 horsepower.  On average it will draw even less power. 
A/C On/off       idle/parked    30mph          55mph
no A/C              4.9hp              18.7hp          27.0hp     
max A/C           7.1hp               22.8hp         30.0hp
delta                 2.2hp                4.1hp           3.0hp

What is the ideal, most fuel efficient cruising RPM?  What is the best gear to be in?
For manual transmissions, lower is better as long as you don’t bog the engine down.  This will depend on the type of vehicle you drive and its transmission gear ratio.  For an automatic, a lighter push on the gas pedal will send it into a higher gear
Look at how the fuel efficiency is effected by what gear you are in.  These measurements were taken while driving on a flat road at a constant 55mph and manually shifting into that particular gear. 

Gear               rpm             mpg
Overdrive       1680rpm      35mpg
3rd Gear         2380rpm      30mph
2nd Gear        3700rpm      18mpg

Angie from Utah:  Does it really save fuel to drive the speed limit?  Driving faster will get you there quicker, but is the extra burn worth it?  5 mph over?  10 mph over? 
Not only will driving the speed limit save you tons on gas, it will save you speeding tickets and in turn, give you lower insurance premiums.  Plus, its safer. 
MPG of 2002 Chevy Venture
mph             mpg
55mph          35mpg
65mph          30mpg
75mph          22mpg

For a 15 mile commute, driving 75mph takes 12 minutes.  Driving 65mph takes 13:50 minutes.  Driving 55mph takes 16:21. 
Assuming you drive to work and back 5 days a week for a year, you will drive 7800 miles a year just driving back and forth to work.  Using the figures above and assuming $4/gallon gas:
Driving 75 will require 354 gallons/year and cost $1418. 
Driving 65 will require 260 gallons/year and cost $1040. 
Driving 55 will require 222 gallons/year and cost $891. 
At the cost of less than 4 ½ minutes each way, you will save $527 in gas each year by driving 55mph instead of 75mph.  That's $44/month. 
All those extra minutes spent and dollars saved, add up to a wage of $13.97/hour, tax free. 

For a short daily commute, a few minutes really doesn't matter much.  But what if you are going on a 600 mile road-trip?  In this case, the time really adds up.  To drive 55mph for 600 miles would take 10.9 hours.  Driving 75mph would only take 8 hours.  At a savings of $40 in gas, your trip will cost you nearly 3 extra hours.  To me, a vehicle full of sticky, tired, crying kids easily justifies driving as fast as possible. 

What is the most fuel efficient speed to travel at? 
That depends slightly on the type of vehicle you drive.  For highway driving, going the speed limit or even slightly under will always achieve the maximum fuel savings. 
Here is a plot of the fuel efficiency vs. speed for my 2002 Chevy Venture. 
mph         mpg
40            32
45            35
50            36
55            35
60            31
65            30
70            26
75            22

While driving 50 is the most fuel efficient speed, it's also painfully slow for a long road-trip.  Driving 55mph during a short commute doesn't use much more fuel and will still get you there in a reasonable time frame.

Ben from Utah: When parked, when is the break-even point of fuel consumption between idling and turning off the engine then restarting it? 
Using a scan gauge tool in my 2002 Chevy Venture van, I measured how much fuel it takes to idle for about 5 minutes.  Then I measured the amount of fuel it takes to stop/start the engine 10 times.  

Idling in park burns 0.3 gallons of gas every hour or about 1 penny of gas every 30 seconds. 
Stopping/starting the engine10 times consumes about 5 cents of gas.  That averages out to 1/2 cent of gas per stop/start.  The break even point is 15 seconds. 

How much fuel is consumed leaving the car in drive vs. putting it in neutral while waiting?
A warmed up engine with the transmission in drive (but not moving anywhere) will consume 0.31 gallons per hour. In neutral will consume 0.29 gph. 
A cold start engine burns 0.8 gph at idle while in park but it steadily drops as the engine warms up.

How much gas does it take to run the A/C or heater on full blast?
When idling, running max A/C uses 59% more gas than just idling alone. Running the heater on max uses 6% more gas. Running the heater and defrost uses 56% more gas, (the defrost also uses the A/C compressor). The rear defrost (which is just a resistive heater in the back windshield) used 3-6% more fuel.

Engine mode                         gph
Idling with max heater             0.34gph
Idling with max A/C                0.51gph
Idling with no heat or A/C       0.32gph

Cruising on the freeway, my Chevy Venture only uses 27HP. With max A/C, it uses 30HP. This is only about 10-12% increase. Well worth it on a hot summer day in my opinion. 

How much horse power does a vehicle use to drive 55mph?  65mph?  75mph?
Speed      horsepower      mpg
55            26.1                   34.3
65            35.1                   30.3
75            47.0                   25.0

Gavin, New Zealand:  Does the octane in fuel affect your gas mileage?  Which one works out to be cheaper overall?  A higher octane fuel will not increase your fuel efficiency one bit.  Don't waste your money.  If you car doesn't care, neither should you. 

Octane          Speed         Throttle position     Ignition timing       gph
85                  30 mph       5                                44                           1.06
92                  30 mph       5                                40                           1.00
85                  in park        0                                18                           0.30
92                  in park        0                                18                           0.31

How does extra weight affect the fuel efficiency of a vehicle? 
I measured the fuel efficiency of my Chevy Venture and then I removed all the seats, weighed them and measured the fuel efficiency again. 
The curb weight of a 2002 Chevy Venture is 3699 lbs.  The weight of 4 removable seats and other misc stuff I had in the van is 288 lbs.  Removing all that stuff, I reduced the van's weight about 8% and at the same time, increased its fuel efficiency by 10%. 

Weight                                   gph           mph
Van with seats = 3699lbs       0.92          33.08
Van no seats   =  3410lbs       0.83         36.54

Does cruise control help fuel efficiency?  It will help your vehicle achieve better fuel efficiency if you tend to drive too fast.  Otherwise, you can do better just by paying attention to the terrain of the road and allowing the vehicle to slightly speed up/ slow down accordingly.  Cruise control tries to maintain a constant speed no matter what the terrain.  This is a very in-efficient way to drive.  Slowing down while climbing hills (even an overpass) and speeding up on the downhills will save more fuel. 

A more fuel efficient cruise control would be a throttle position sensor control, or an intake manifold vacuum pressure control or a fuel gallons per hour control.

Coasting in Neutral or In Gear?

I found plenty of opinions and bad science on this topic but there is no conclusive evidence available to settle this debate.  Which one saves more gas when coasting?  Shifting into neutral or staying in gear?

My philosophy is:  If you can't find someone from which to copy the answer, FIGURE IT OUT YOURSELF! Then write a blog about it.

The Neutral Camp: Shifting into neutral allows the engine to run at its lowest RPM but the engine has to burn a small amount of fuel to keep itself running. Very little resistance is applied to the motion of the vehicle.

The Keep it in Gear Camp: Keeping it in gear, the vehicle's computer senses the reduction in power demand and shuts off fuel to the fuel injectors. When costing in gear, the engine is essentially off. This added resistance acts like an engine break, slowing the vehicle down but it does so with almost no fuel consumption.

Both sides have a valid argument. As I research ways to achieve higher fuel efficiency, I find myself changing sides back and forth. 

Using my newly acquired Scan Gauge II, I am now able to accurately measure instantaneous fuel economy. Since the late 1980's, every single fuel injected vehicle on the planet has had the ability to monitor its instantaneous fuel economy but almost every automobile manufacturer chooses not to include this "planet saving" feature in their vehicles. Why? I don't know.

While driving my wife's 2002 Chevy Venture, I found a less-busy section of interstate where I could setup and run the test.  With the aide of my mom who was traveling with me, I recruited her to assist me in recording the data. 47 years ago, she typed my dad's Masters Thesis.  Mom was more than capable of writing down a few readings while I focused on keeping the van traveling between the lines.

After I accelerated above the desired speed, I let off the gas until the van began coasting. This allowed the van to settle out and decelerate to the correct speed. Note:  All freeway speed measurements were taken on a flat, strait stretch of road during a high wind storm. This unusual weather provided a nearly constant 25mph tail-wind which allowed the vehicle to decelerate more slowly. This aided me in taking more accurate, high speed readings.

Initially, the data was inconclusive. The first 2 sets of data showed that coasting in neutral got better gas mileage. The second set of data points revealed that keeping the van in gear was the more fuel efficient choice.

I decided to try this experiment again later that night, this time running at slower speeds in an undeveloped residential neighborhood. By this time, the wind had died down to only a few mph.  With the aid of my 9 year old daughter, we ran 2 sets of “coast tests” at 30mph and 2 sets at 25mph. Each set was driven in an opposite direction to eliminate the wind as a factor. But once again, the first 2 tests revealed that Neutral is the superior choice and 2nd set of tests demonstrated that coasting in gear was better.  What is going on here?

Glancing down at the Scan Gauge II display, it hit me. Engine temperature!!!

When an engine first starts up, it is running at temperatures that are out of the operating range of some of its sensors. To combat this, the vehicle's control system runs in an "open loop" (does not receive feedback from its sensors) so it plugs in default values for the sensors.
As the engine warms up, the engine's control system switches over to “closed loop” where it makes decisions based on the actual readings from the sensors.

While running with a cold engine, coasting in gear gets lower fuel efficiency and coasting in neutral achieves higher efficiency.  After the engine warms up, the opposite is true. 
Update 5/1/2011:  The effect I was seeing is not related to the closed loop/open loop.  After more tests, my wife's Chevy Venture goes into closed loop within a few seconds of starting up the engine.  Whatever the phenomenon, the increased in-gear efficiency only happens after about 10 minutes of driving and after the engine coolant temperature reaches about 185 F.  I assume it is when the thermostat opens.  Whatever the effect, it is re-producible, predictable and measurable.

The following readings were taken on 3 separate occasions, each while the the engine was cold.

Note:  instantaneous fuel efficiency readings can be extremely high while coasting at high speed. 

Engine very cold in the early morning
75mph run   Gear       mpg
Run#0          Neutral    140mpg
Run#0          In Gear     97mpg

Engine cold in afternoon and very high tail-wind
65mph run   Gear         mpg         RPM
Run#1          Neutral      176mpg     900rpm
Run#1          In Gear      170mpg    1800rpm
Run#2          Neutral      188mpg     914rpm
Run#2          In Gear      186mpg    1630rpm

Engine cold at night and low/no wind
30mph run   Gear        mpg          RPM
Run#3          Neutral      82mpg       769rpm
Run#3          In Gear      69mpg       894rpm
Run#4          Neutral      89mpg       737rpm
Run#4          In Gear      76mpg       878rpm

The following readings were taken on 2 separate occasions, each after the engine had warmed up.

Engine warm ~195 degrees
25mph run   Gear        mpg           RPM
Run#1          Neutral      62mpg        858rpm
Run#1          In Gear      64mpg        875rpm
Run#2          Neutral      63mpg        858rpm
Run#2          In Gear      64mpg        855rpm
Run#3          Neutral      67mpg        814rpm
Run#3          In Gear      69mpg        828rpm

30mph run   Gear        mpg            RPM
Run#4          Neutral      80mpg        858rpm
Run#4          In Gear      83mpg        847rpm
Run#5          Neutral      82mpg        825rpm
Run#5          In Gear      85mpg        792rpm

55mph run  Gear          mpg           RPM
Run#6         Neutral       154mpg       890rpm
Run#6         In Gear       155mpg      1080rpm

70mph run  Gear         mpg           RPM
Run#7         Neutral       200mpg      900rpm
Run#7         In Gear       205mpg      2000rpm (WOW!!)

Conclusion: With a cold engine, coasting in neutral uses 12% less fuel than coasting in gear. (at least for the default values in the computer of my wife's 2002 Chevy Venture). When the engine is warmed up, it flips the other way and coasting in gear saves on average 2.7% more fuel than coasting in neutral.

If you drive a manual transmission and have a short commute (less than 15 minutes), you will be better off coasting in neutral as most of your commute will take place with a cold engine. If you drive an automatic and/or have a commute that lasts longer than 15 minutes, coast in gear. It's probably better to leave it in gear anyway just for the safety and convenience aspects.

I may only be getting only 20mpg while driving 75mph but during that 5 seconds span when I am coasting at freeway speeds before pushing on the gas again, my van is getting over 200mpg.
Using a tool like the Scan Gauge II allows for super accurate measurements of high fuel economy during these very specific types of driving.
Although these short periods of excellent fuel economy make up only a small portion of a normal commute, they contribute to the overall fuel and cost savings.
Now that each one has been quantified, you can now decide which method best suites your personal driving preferences. For a warm engine, there is only 2.5% of variation between the two methods and for most people, that's small enough to say “who cares?” That's fine but at least now we know.

Pimp My Doorbell Button

A newer version of this article is located at my new website at John Saves Energy


Most appliances draw a tiny bit of power all the time in exchange for a convenient or useful purpose. For example, a cordless phone with base station, a TV with remote control or the microwave oven with its glowing clock and fancy Lieutenant Commander Data console touch buttons.

Now don’t get me wrong. Doorbell lights are helpful, convenient and luxurious.  Not only do they pinpoint where the doorbell is located, but pushing the button turns the light off, indicating to the visitor that the doorbell rang inside.  Oooo fancy! 
"But why would I want to aid the Kirby salesman at being able to reach me better"? This is a discussion for a later blog topic, "How to electrify door-to door Solicitors with 24,000 Volts while still keeping little Jimmy and Mrs. Snow (from down the street) out of harm’s way".

When I find that an appliance in my house draws power all the time for no good reason, its gets shut off. For example, the sprinkler timer and A/C compressor during the winter time.
As I near the end of my list of phantom power consuming appliances, I’m starting to look at the efficiency of these devices. Why should a TV draw 20 watts in standby when it could provide the same function drawing less than 1 watt?
One night while turning off the porch light, I noticed that the doorbell light was providing quite a bit of light all by itself. It seemed like overkill that this doorbell indicator was acting more like a beacon of hope for tempest tossed sailors than a doorbell light.

A doorbell is a simple circuit. It has a low voltage transformer that steps 120 volts AC down to about 21 volts AC which then runs through low voltage wiring to the doorbell switch. The doorbell switch has a small incandescent bulb wired across it. The tiny light bulb provides light but has too high of resistance to actuate the solenoid. When the suspecting visitor pushes the button, the circuit is closed, shorting out the light and energizing the solenoid.
The solenoid has a small hammer that compresses a spring and smacks into a "ding" bar, (I just made that up). When the switch is released, the solenoid de-energies and the hammer flies back the other way into a "dong" bar, (ha ha, I’m such a dork). 

During the "ding-dong" sequence the entire circuit draws over 2 amps from the 21 volts AC provided by the transformer. The total power consumption is about 50 watts but only lasts the length of "ding dong", so who cares. 

Even with all my fanaticism, I don’t lose any sleep over a dinky 50 watt ding dong. If someone were to ring my doorbell for ½ a second, 20 times a day, every day for a year, aside from me trying to kill them, the total time spent ringing the doorbell would only add up to 0.5*20*365 = 3650 seconds or ~1 hour per year. At 50 watts, that would only cost ½ cent per year.  

What concerns me is the power draw of the incandescent doorbell light itself. The continual power draw of my doorbell (with light) is about 4 watts. That might not seem like much but if you consider that it runs 24-7 all year long, that adds up to 35KWH annually and costs $3.50/year.
"That’s still not a big deal" you say? Well, saving a little energy everywhere really adds up. After all, "Find a penny, pick it up, all the day you’ll be a scrounge. A scrounge who just made a penny that is".
The heady days of the incandescent indicator peaked around the time of the original Star Trek series. Today the indicator light of choice is the LED. 

My original LED doorbell design started out as a simple white LED with a current limiting resistor. That works okay but since the LED is being powered off of alternating current, it flickers at 60 Hertz. I don’t know about you but that annoys the crap out of me. It might even send poor aunt Edna into an epileptic seizure each time she steps foot on my porch. I must rectify the situation.
I modified the circuit to include 4 diodes and a 3.3uF capacitor. 3.3uF was chosen for exactly 3 point 3 reasons: 

1. I already had one
2. It's large enough that the LED won’t flicker and
3. It's small enough that the LED will go out when the button is pushed.

To my dismay, my circuit caused the doorbell circuit to ring continually with an annoying solenoid buzz.
In Chinese Accent:  "Confucius say: A ding with no dong is dung". 
Adding a 1.8K resistor in series with the rectifier stopped the solenoid from triggering.

For comparison, I measured the current draw of both lights. 
Incandescent Light:  21.8VAC   75mA    1635mW
LED Light:                21.8VAC     3mA        65mW
Less power draw on the inefficient low voltage transformer and less current leaking through the solenoid resulted in even more power saved. The 1.5 watt savings from swapping out the incandescent light nearly tripled into 4 watts when the power consumption was measured on TED.

You may say that 4 watts is a trivial power reduction. That may be true, but the sailors sure are furious. 

Even Coal Is A Renewable Energy Source If You Wait Long Enough!

If you think about it, everything on Earth is solar powered.  All the coal and oil in the Earth came from plants and animals millions of years ago that grew by the light of our sun.  The mechanisms that bring us wind, rain, and rivers are all powered by the sun.  Without the sun, we would not have any energy.  Solar power is the past, present and future of our energy production.  But this is a topic for another day so let's get back on track shall we? 

According to Wikipedia, the total global electric power consumption is 15 TW, (15,000,000,000,000 watts). The potential available solar power is 86,000 TW.  That's almost 6000 times more than we, the people of Earth currently need.  The available wind power is 870 TW and the available hydroelectric power is 7.2 TW.

According to Technology Futurist Ray Kurzweil, the total amount of solar energy being produced every year is doubling every 2 years.  In 8 more doublings, he says that solar power could generate enough energy to supply all our energy needs.

Not to say that he's right or that this will happen, but the stage is being set for a great paradigm shift in the way we power our homes, our cars and for that matter, world economies.  

Solar power alone cannot provide all the world's energy needs. We still need something that works at night and when it's cloudy.

The Eventual world wide renewable energy solution will be solar and wind power with hydroelectric acting as the regulator and battery back up for it all.

There are currently 60 planned or operational pumped-storage hydroelectric stations larger than 1 GW world wide.  These work by pumping water to an upper reservoir during times of excess energy production and releasing it to the lower reservoir during peak demand.  While most of these utilize conventional power plants to pump the water, solar and wind power is the next logical step.