Range can be shortened if we take the Porsche out on the freeway and drive at 85 miles an hour, not so much because of the speed of the motor, but from the air resistance from 45 miles an hour up to 85, it increases dramatically and causes a little bit more power to be used, quite a bit more power to be used just to go down the road. If we idle around town here at 25, 30 miles an hour, we could probably do 100 miles on a charge on this car. Beyond that, we haven't really run the batteries completely flat in doing that.
At 100% discharge, it probably would be more like 100 mile average. However, it's important that we maintain our batteries at a discharge level no greater than 80%. And that takes me to some of the considerations about charging and the batteries themselves.
How long it takes to charge the car, again, varies depending on how much energy we've taken out of the pack. If we've taken the full 80% or 144 amp hours out of the pack at home in the garage using a 240-volt AC system, I can charge this battery pack in about 4.8 hours. If I plug it into a 120-volt AC system, it's going to take correspondingly twice as long, nine to 10 hours.
In actual practice, it doesn't take either one of those, and we'll talk a little bit about why. The charging process is pretty simple. The Porsche, like most of the Volkswagens, the Beetle, had the gas tank up front, so you had to open the hood.
And we followed that metric in doing this and put a small Revco recessed male three-prong connector in the front of the car. Beneath our protective cover, we've got essentially a standard three-prong male plug in a recessed receptacle. To charge it, I have a cord here in the garage made especially with a 240-volt connector on one end and, again, an ordinary 120-volt AC female connector on this end.
And we left the weather cover plug the cord in and walk away. We use the three-prong connector, which is somewhat unusual when using a 240-volts AC. The cable and the connector are nominally rated for 15 amps.
This is a very heavy cord, and when you do this, you want a good quality cord, not a lamp cord, with a very well-insulated, heavy connector blades and actually 10-gauge wire within the cord. And so for a short distance of 20 or 25 feet, it's well able to carry the current. The reason we have this setup is I also carry a 25-foot cord in the car.
In theory, if I was out somewhere and wanted to take advantage of an opportunity to charge at work or at a friend's house or the store, whatever, I could pull this out, plug it into any 110, 120-volt AC receptacle, and charge the car for a little while and have enough juice to get home. In practice, you can see I don't even have the wrapper off the cord. But that's the concept, is to be able to charge either way.
The charger we use is a Brusa model NLG511. This is a $3,000 charger that comes from Switzerland. It's a little bit over-engineered and a little bit overpriced, frankly, but it gives us several advantages.
The charger, which I can't really show you, it's located between the front wheels and underneath the fiberglass front compartment. It's connected to the batteries all the time. This Revco connector, where I plug it in, has a cable that goes to the Brusa charger.
And the Brusa charger will first operate on any AC voltage from 90 to 300. And so it can swing both ways. We can charge from 120-volt AC or we can charge from 240-volt AC without making any configuration changes to the car at all.
And that's why we set up this connector, where at home, I have a cord. The other end of this cord actually has a standard L6-30 30-amp 240-volt AC connector. You can get it in a hardware store.
And I have a similar female receptacle on the wall hooked up with a 60-amp circuit, which is twice what this is rated for, but I wanted to have plenty. And so this is the cord I use at home to put 240-volt AC into the charger through a standard 120-volt AC three-prong connector. The other thing that that does is this charger provides quite a bit of power, particularly in the 240 volts.
We can charge at 30 amps. There aren't very many chargers. Perhaps this one in Manzanitas that can produce that level of power in that small a package.
And in a small car like this, we have to have a small package. Do you have to spend $3,000 on a charger? We wanted one on board, but you can get chargers that do just as much current, the same voltage, and will charge car in the same amount of time. Most of them are about the size of a small dog house and have a big cooling fan and so forth to handle that amount of power.
So the Brusa gives us a small package with very flexible AC input power, and it's quite programmable. Underneath this casing, I've got a RS-232 connector that I installed that connects to the Brusa and allows me to hook up a laptop computer. We'll talk a little bit more about that in a bit.
First, let's talk about batteries. Most of the electric cars out there that people convert use lead-acid batteries. This is largely due to cost.
The lead-acid batteries for this car, had I gone that route, would have only been about $2,500, and the car would operate pretty well. It wouldn't go as far, and part of that is the weight. The lead-acid system, configured as I have this, would be about 1,350 pounds just in batteries.
The batteries we did use are Thundersky lithium-ion iron phosphate batteries from Shenzhen, China. They've just become available in the last year. People have started to use them, but looking around on the internet, I can find less than 35 examples of cars that are actually running on these batteries.
So as a result, some very helpful and knowledgeable and authoritative people have provided me a lot of advice. Most of it derived from lead-acid battery experience, and almost all of it, 100% misinformation. And so we've had to learn quite a bit about these batteries.
The good news is they make an electric car viable in a way that the lead-acids simply do not. These particular batteries in this car, we have 16 four-cell batteries, if you will, in two eight-cell banks, and their total weight is 475 pounds, about a third what the lead-acid weight and volume would be. And they have much higher energy density.
This is an example of one of the batteries we have in the car. This is their 90 amp hour type cell. They actually come in individual cells.
I have four of them here strapped together with the copper straps that you would use to connect them. They have two aluminum end plates and some straps to bind them together. And that's because they do have a tendency to swell up when they're under a heavy discharge or charge regime.
And so you have them kind of clamped together. The swelling isn't really harmful. You want to contain it mechanically, but it doesn't do anything to the battery.
These batteries have a nominal voltage of 3.2 volts per cell. And so we have about a 12.8 volt cell.