Let's take a simplified look at how hybrid cars work.
Hybrid electric car engines are made up of two different motors that are responsible for moving the vehicle. Because the load is now shared by two power sources, the fuel economy increases since some of the power comes from the electric motor and some comes from the gas motor.
Of course, it's not that easy. Because of the extra weight from the battery, it's actually harder to move the vehicle. Another problem is in how you charge the battery. If your only source of power for the battery comes from the gas engine, you would lose out in the energy transfer from the gas engine to the battery pack to the wheels, rather than a more direct route of gas engine to wheels.
That's where regenerative braking comes in. By taking in the energy you normally lose to friction and heat and put it back into the battery pack, hybrid cars can increase the fuel economy by a truly significant amount, depending on the system.
But, if you can recharge the battery pack through the electric grid, in other words plug the car in, you take even more of the pressure off of the gas engine.
I know, it looks like I'm straying a bit, but stay with me.
The X-Prize is a $10 million competition to "design viable, clean and super-efficient cars that people want to buy." The team "that win a stage race for clean, production-capable vehicles that exceed 100 MPGe" will be the team that wins. The winning team will have developed a "real, production-capable cars that consumers want to buy, not science projects or concept cars."
Alphacore, a business from CT, thinks it may have met the challenge presented by the X-Prize committee by doing things a little bit differently. Rather than building a new car altogether, they are putting together a kit (that will be ready to go in June!) that turns a normal car into a hybrid electric plug-in for only $3300 ($600 to install).
So, there's no regenerative braking system. No onboard computer system to check with. No complicated system to mate the two motors together. Since there are fewer parts, the cost comes down. More importantly, the system works with any car.
The electric motor is attached on the outside of the wheels and is powered by a 72V 120Ah Deep Cycle Lead Acid battery pack with six batteries inside, located in the trunk. Those batteries are recharged through an onboard charger, which is installed next to the batteries.
By doing so, the team at alphacore believes they can turn any car that gets a normal fuel economy into an extraordinary gas sipper.
- On-Wheel motors: Brushless DC construction. Dimensions 14" diameter x 2". Weight 35 lb. Rated power: 10KW = 13.5 HP (motors on two wheels).
- Adapter plates: 4 and 5 bolt patterns, available with 100, 108,114.3mm(4 1/2") and 120mm bolt circle diameters fitting app. 95% of cars.
- Motor controllers (2 pc) 72VDC max 120A (one per motor).
- Batteries: 6 pc. 12V 120 Amp hours lead/acid deep cycle, or 4 KWh Lithium-ion battery pack (Expected available from several sources by mid 2008).
- On board charger: 72 Volts/10 Amp.
- Total Weight: App. 300 lb with lead acid batteries, 200 lb with Lithium Ion batteries.
- Added un-sprung weight, 38 lb per wheel.
Everything I've seen on the Poulsen system lists the battery pack as a lead/acid deep cycle battery. But in the specs (from the poulsen site), they list a possible alternative as a Lithium-ion battery pack. That makes me wonder about what the measurements would be from the Li-Ion pack? Also, will the cost be different? I would assume it could go way up, but would you get more bang for the buck?
What kind of results are they seeing? I know the competition is to produce a car that can get over 100 mpg, but since the test vehicle they show is a 2003 VW Jetta Diesel, I'm wondering what a car with average fuel economy figures would get?
How durable is the system? How long will the lead/acid battery pack last? In modern hybrid cars, computer systems keep track of the charge remaining on a battery pack, making sure it doesn't get too depleted or too charged. That makes the battery last longer. Is the recharging system keeping track of the charge left? Or does it keep the electric motor running until it can't run anymore. If you had to replace the battery pack, how much would it cost and how often should you expect to do so?
What happens if you want to remove the system altogether? Is it hard to do so?
I would guess that if you had a short commute, you would do better than in a long commute, simply because you probably would not be able to recharge at your location, like you would at your home.
I think this is an exciting system. A fairly cheap method for updating any car? The cost savings in gas could be enormous if you really can go improve by 30, 40 or 50 mpg.
Sources: Poulsen Hybrid, Alphacore, X-Prize, orange hues, Autobloggreen, and USNews.