Category Archives: Technology

Leveling up

To take advantage of an electric vehicle you really need a Level 2 EVSE installed at home unless your daily commute is roughly half of the vehicles range (I’m speaking of the “low cost” BEVs with a range of ~100 miles–a 300 mile Tesla Model S is a different story). At Level 1 charging rates a completely empty battery could take as much as 20 hours to charge–much longer than your average night time.

Level 2 EVSE’s can cost a few hundred dollars (the DIY versions) to up to about $1000. Do some research; you may find deals and/or rebates. For myself I found a $2500 rebate towards the price of the EVSE and installation from my power company. The deal also included me in the EV program for time-of-day rates on electricity (charging at night reduces my electricity cost by a factor of 4). The program was part of Bosch’s “Plug In Now” EV business (formerly SPX). Note 1: you can even search for incentives in your area on that link. Note 2: You need to have possession of the EV before you can use that program.

The installation process was pretty easy: They first send out a contracted electrician to quote on the installation (funny that it always seems to come very close to or above the $2500! at least from the few I’ve talked to who also did this). After the quote is approved by you and Bosch they order the EVSE. Once the EVSE arrives they schedule a date to come out an install it. Now the fun begins: You can start charging at Level 2 speeds (at this point you may not be billed for the EV separately yet as the power company has to then come out and install a 2nd meter).

My Bosch EVSE

My Bosch EVSE

Using a Level 2 EVSE won’t use any more power than the Level 1 EVSE: The car still charges to whatever battery level it has; it just does it faster. In many cases Level 2 charging is slightly more efficient and thus will use less power.

Now you may ask: What does that really do to your electric bill? Using all that electricity it must be a lot! (A question I just received recently) To that my answer is below: Exhibit A my EV electric bill for the first month:

First months electricity bill for the FFE

First months electricity bill for the FFE

Yup: One month of driving around in my car cost me a whopping $37.79! In our ICE Focus the same commute was costing me $200+ per month in gas.

 

Fill ‘er up

When I tell people that I have an electric car I get the usual spate of questions: Has it ever left you stranded? How far can you go? Do you have to charge it every day? (As if that is such a huge inconvenience!) What do you do if you run out while away from home?

The quick and simple answers are: No, about 75 miles, no, you plan so that doesn’t happen.

Lets start with charging and the big misnomer: The thing on the wall with the chord that you plug into the car is NOT a charger, its called an EVSE: Electric Vehicle Supply Equipment. It is basically a smart GFI. The actual charging circuitry is inside the car. The EVSE provides a safe connection to electricity. There is a sense line where the car knows if it is plugged in or not, and how much current that the EVSE can provide to the car (which also determines how fast the car can charge up). The J1772 specification, which governs everything about EVSE’s, is actually spec’d out up to 80A (which could charge my car in about 2 hours or less if the car could handle it). The actual charge time is determined by the lesser of the supply current or the power rating of the internal charger in the car (my FFE’s charger is rated at 6.6kW). (The “No” answer above to: “Do you have to charge daily” is true depending on how much you drive. If you only drive 5 miles a day then no you don’t have to charge daily–just like an ICE car: If you empty the tank in a day then you have to get gas daily!)

Now the big deal, or at least it is for most people who ask, charging daily: You plug in your cell phone every day (sometimes more than once per day) how is that less of a hassle than plugging in the car? For myself I just get in the habit of plugging the car in every time I get home–every time, whether I know it will charge or not. It really only takes seconds to grab the cable, open the charge port door, and plug in (I do listen for the cycle the relays make as I’m unloading or locking or otherwise walking away from the car to make sure everything is working). For those few seconds I’m saving a 30 minute round trip to the gas station and back (of course this refers only to the times when I make a specific trip to the gas station, but even just stopping on my way in to work adds 10-15 minutes to my commute).

Here is something to think about as well: If you plug in daily, and charge nightly then every morning the car has a “full tank”. What “range anxiety”? I rarely drive more than about 60 miles a day. On a normal day I barely look at the battery gauge; don’t even give it a passing thought. Conversely when I get into one of our ICE vehicles the first thing I do is check the gas gauge to see if I have enough!

You do have to get a Level 2 charger at home though, that makes all the difference (Level 2 = 240V and can charge the car at its maximum rate). The “convenience chord” that comes with the car (most EVs come with one) is called a Level 1 chord that can be plugged into 120V–the slowest possible speed to charge (up to 20 hours in my case). I was able to find a deal through my electric company that covered most of the cost of the install..

Technology/Efficiency

Taking a break from the story for a bit.

Here I am going to go into a general discussion of the differences between various vehicle propulsion methods: Gas engine, hybrid, and electric motor.

Your normal gas engine operates at about 18%-20% efficiency. Much the losses associated with gas engines are attributed to heat loss through the exhaust and friction in the drive train. This can be increased slightly by adding turbo or super chargers but they only bring the engine closer to its theoretical maximum efficiency (37%).
Electric motors, on the other hand, have an efficiency in the range of 85%-90% thus more of the “fuel” will go to moving the car. This also poses a problem as there isn’t enough waste heat to be used for other purposes (heating the cabin, warming the batteries, etc.). This large difference gives the electric car an advantage in “fuel” economy.

Now lets look at other aspects of the vehicle: What is the one thing that a car does that wastes the most energy? Its not acceleration; its stopping. Think about it: What do brakes do? Brakes turn the forward momentum of the vehicle into heat at the braking mechanism. All of this heat is dissipated into the air–just thrown away.

How can we recover that lost heat? There is no way to feed that back into a gas engine and re-create gasoline. What you can do is spin up a generator and store the electricity. This is the exact principle used by hybrid vehicles: There is a motor/generator that recovers the stopping momentum and puts it back into a battery for use during acceleration (this is what regenerative braking does). Hybrids aren’t designed to run on electricity alone–the battery isn’t large enough–they are only designed to capture and re-use the deceleration energy (for the most part).

Now adding all the equipment for a hybrid increases the vehicles weight by a significant amount (we now have two “engines” and two “fuel” tanks). Manufacturers make a tradeoff between the sizes of the engine, motor, fuel tank, and battery when designing the hybrid car.

An electric car does not suffer from that limitation–only one motor is present and one “fuel” tank. In addition the electric car can make full use of regenerative braking.

Given all these advantages an electric car has one huge drawback to it (as you are probably screaming at your screen about now LOL): The energy density in today’s batteries is nowhere even close to the energy in a tank of gas. There is a ton of electricity storage research (battery, super capacitor, air-battery, etc.) going on with the goal of giving today’s electric vehicles more range. I’ve read of a few people posting their opinions for the battery criteria required for BEV’s to go mainstream. Jumping into the fray here is my guess as what is required for mass adoption of BEVs:

  • BEVs must have a range of 250+ miles (Not saying 300+ miles because one of my ICE vehicles (a rather large truck) only has a range of 250 miles on a tank)
  • The battery in said BEV of range 250+ miles must be not much larger than the average tank of gas (note that the battery doesn’t have to have the same energy density of gas due to the electric motors higher efficiency)
  • There must be available charging stations to allow the 250+ miles to be replaced in approx 10 minutes or so

Easy as pie right? The Tesla Model S comes really close to all of those above with a luxury price tag. The sub $30k planned Tesla model should take the market by storm..