I have been working hard to find the facts about charging electric cars. Tesla has some new special charging stations that are rated at 90KW. Exactly what does that mean? That is the point of this blog.
To understand all of this, you don't have to be an Electrical Engineer, but it helps. Let's start with the 90KW figure. We are all familiar with the common 100 watt light bulb. If powered by the standard 110 volt circuit, the 100 watt light bulb consumes 0.91 amps. For the record, most modern homes have a maximum power input of 200 amps at 220 volts. That means you could run a maximum of 440 100 watt light bulbs. You would be consuming power at the rate of 44 KW. If you were paying $0.15/KWH, it would be costing you $6.60 per hour. Now, let's look at the electric car.
From the best that I can determine, it takes about 50 hp to run a normal car at 50 mph and a hp is equal to 750 watts. Notice above that the total power from your home's electrical system is just 44KW while the Tesla charging station is rated at 90KW. To drive your electrical car at 50 mph for one hour requires 37.5KWH of energy. If your charging system were 100% efficient and you used 100% of your home's power to charge the battery, for every hour you were on the charger, you could drive 1.17 hours or 59 miles. That amount of power would have cost you $6.60.
For comparison, in my town, gas costs $2.50/gal and I get about 25 mpg. That means to drive the same number of miles above, I would burn 2.36 gal of gas that cost me $5.90. Notice also that part of the price of the gas was taxes to build and maintain the roads a bridges that I was driving on. We need to count that some place, but my main point is about the charging time.
With the Tesla special charging station, if you are the only person plugged in, for every hour you are on the charger, you could drive for 2.4 hours. I know that anyone who can afford a Tesla or any other all electric car has to be earning well over $50.00 per hour. Who is counting that "dead" time while you are sitting in charging station. I just filled up my truck with 41 gal of gas in about 10 minute. I can now drive about 1025 miles before I have to fill up again. My gas fill time for the 2.4 hours of driving above works out to 1.17 minutes compared to the 60 minutes of the Tesla above. Who is counting?
I am still working on claims that there is some new battery that can be recharged in "one" minute and can then go for 500 miles. That system sounds like a bomb to me. For a system like that, I would think that you would need a "blaster's" license.
PS--Here is a point about the electric power system of your home. If you were to use 100% of your home's electric power to run an electric motor, the biggest motor you could run would be 58.7 hp. As I pointed out above, it takes about 50 hp to run a typical electric car 50 mph down the high way. If you come to a hill, you will not be able to drive 50 mph. You will have to slow down. If it was cold and you had to wait for one of your children to get out of school, much of the energy in your battery would have to be used for "heat". This would significantly reduce how far you could then drive.
To understand all of this, you don't have to be an Electrical Engineer, but it helps. Let's start with the 90KW figure. We are all familiar with the common 100 watt light bulb. If powered by the standard 110 volt circuit, the 100 watt light bulb consumes 0.91 amps. For the record, most modern homes have a maximum power input of 200 amps at 220 volts. That means you could run a maximum of 440 100 watt light bulbs. You would be consuming power at the rate of 44 KW. If you were paying $0.15/KWH, it would be costing you $6.60 per hour. Now, let's look at the electric car.
From the best that I can determine, it takes about 50 hp to run a normal car at 50 mph and a hp is equal to 750 watts. Notice above that the total power from your home's electrical system is just 44KW while the Tesla charging station is rated at 90KW. To drive your electrical car at 50 mph for one hour requires 37.5KWH of energy. If your charging system were 100% efficient and you used 100% of your home's power to charge the battery, for every hour you were on the charger, you could drive 1.17 hours or 59 miles. That amount of power would have cost you $6.60.
For comparison, in my town, gas costs $2.50/gal and I get about 25 mpg. That means to drive the same number of miles above, I would burn 2.36 gal of gas that cost me $5.90. Notice also that part of the price of the gas was taxes to build and maintain the roads a bridges that I was driving on. We need to count that some place, but my main point is about the charging time.
With the Tesla special charging station, if you are the only person plugged in, for every hour you are on the charger, you could drive for 2.4 hours. I know that anyone who can afford a Tesla or any other all electric car has to be earning well over $50.00 per hour. Who is counting that "dead" time while you are sitting in charging station. I just filled up my truck with 41 gal of gas in about 10 minute. I can now drive about 1025 miles before I have to fill up again. My gas fill time for the 2.4 hours of driving above works out to 1.17 minutes compared to the 60 minutes of the Tesla above. Who is counting?
I am still working on claims that there is some new battery that can be recharged in "one" minute and can then go for 500 miles. That system sounds like a bomb to me. For a system like that, I would think that you would need a "blaster's" license.
PS--Here is a point about the electric power system of your home. If you were to use 100% of your home's electric power to run an electric motor, the biggest motor you could run would be 58.7 hp. As I pointed out above, it takes about 50 hp to run a typical electric car 50 mph down the high way. If you come to a hill, you will not be able to drive 50 mph. You will have to slow down. If it was cold and you had to wait for one of your children to get out of school, much of the energy in your battery would have to be used for "heat". This would significantly reduce how far you could then drive.
