Frequently Asked Questions: Fuel Cell Car & Experiment Kit
Q: What kind of fuel cell does the Fuel Cell Car & Experiment Kit use?
A: The fuel cell uses a Proton Exchange Membrane or PEM fuel cell. PEM Fuel Cells utilize the energy from the electrons given up by hydrogen ions (or protons) during the reformation of water across the membrane to run the car’s motor. The fuel cell is “reversible” meaning that it can both split water into hydrogen and oxygen, and combine hydrogen and oxygen into water.
Q: So you’re telling me this car runs on water? What else do I need?
A: All you need is distilled water and sunlight (or light from a bright lamp) to power the car.
Q: Is this thing safe?
A: Yes! The fuel cell car is safe, reliable and efficient. If only we could get a full-sized fuel cell car to work as well! The fuel cell generates gases that are easily ignited, but the tanks do not hold enough gas to be dangerous. Still, we recommend that the kit should only be used by persons 12 and up, and only under the supervision of adults who have familiarized themselves with the safety measures described in the manual.
Q: How much voltaic force is generated during the various processes performed using the Fuel Cell Car and Experiment Kit? How much amperage?
A: During solar-powered electrolysis, you can expect to generate about 1.7 Volts at about .7 amps. When this process is reversed, the fuel cell has a No-Load Voltage of about 1.7 Volts and an Operating Voltage of about 0.9 V.
These numbers were experimentally obtained at our test facility using a 75 Watt incandescent bulb as the light source for the electrolysis. Your findings will almost certainly differ to some degree. Values will increase for experiments done in sunlight.
Q: What are the dimensions of the constructed model car?
A: The car has an overall length of approximately 20 centimeters (8 inches) by a width of approximately 12 centimeters (4 3/4 inches). The height of the car is about 8 centimeters (3 1/8 inches). These dimensions don’t include the removable solar panel, which is a flat rectangle about 12.5 cm (5 inches) wide by 13.5 cm (5 1/4 inches) long.
Q: How much light is needed to run electrolysis?
A: We’ve found a 75 Watt incandescent bulb adequate for all of the experiments in the manual. Sunlight is always a better choice of course, if available.
Q: How long will the fuel cell car run on a full tank of hydrogen?
A: On a full tank of hydrogen (approximately 24 ml) the car will run for up to half an hour under optimum conditions.
Q: How long does it take to collect a full tank of hydrogen using electrolysis?
A: In full sun, the fuel cell will split enough water to fill the tank in about ten minutes. Using a 75 Watt incandescent bulb, this will take closer to 15 minutes.
Q: How often do I need to replace the water in the fuel cell?
A: Not very often. Because the fuel cell is a reversible fuel cell, the water gets split into hydrogen and oxygen during electrolysis and then that hydrogen and oxygen are re-combined back into water. The water can be used over and over again. Of course, you will lose water to evaporation and spilling, and thus you will need to replace the water periodically.
Q: Regarding the subject of Fuel Cell efficiency (pg 90); you use a voltage ratio rather the conventional Power ratio as used for the calculating the efficiency of water electrolysis on page 67. It is calculated and stated as an "overall efficiency" but labeled as a "Fuel Cell efficiency".
Noting your statement "the formula is not completely correct" can you explain this so we can clear it up with students, if asked?
A: The formulae utilized for the experiments mentioned above are different because of the fundamental difference between Power and Efficiency. Power is a quantifiable value - a "something" if you will. We call it a "something" because it has units; Power is the measure of Joules of work done per unit time. If something does 1 Joule of Work every second, (1J/s) it has a measurable Power of 1 Watt.
Efficiency is simply a fabricated number - if you notice, it has no units; it's not a "something", in other words. It's a simple method to ballpark the amount of energy you're getting out of a machine compared to the amount you're putting in. The formula given is not "completely correct" because in order to calculate true efficiency, ALL factors affecting the performance of the fuel cell must be accounted for. The increase in accuracy isn't worth the added calculation of such factors as friction, drag in the fluid tubes, whether or not you've got stray ions in your water, and so on.
Print This Page
First, add water and watch it separate into hydrogen and oxygen. Then, use those stored gases to power your vehicle across the floor. Now that we have your attention, roll up your sleeves and find out more through experiments and demonstrations you can do on your own, in a classroom or with friends.
Fuel cells are a promising means of producing energy in the future. Some fuel cells, such as this one, do not consume fossil fuels and therefore are considered environmentally friendly. Automobile manufacturers are already experimenting successfully with this technology and it is widely believed that fuel cells will power automobiles and many electronic devices, including laptops and cell phones, in the near future.
can build your own experimental reversible fuel cell car to learn more about this energy source. With more than 30 experiments and demonstrations, users will learn how a reversible fuel cell works to perform electrolysis as well as to create energy. The electricity required to activate electrolysis is created with a large solar cell included with the kit. During electrolysis, water is separated into hydrogen and oxygen and the resulting energy is stored as a gas. When needed, the gas is fed into the fuel cell, which then serves as the power source.
Experiment Manual offers over 30 experiments, including:
The Thames & Kosmos Fuel Cell Car & Experiment Kit won a Silver Award from the Parents’ Choice Foundation in 2002. Here’s their review:
