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Fuel Cell User Guide
Introduction
The information in this document provides instruction on the proper way to setup,
charge, and use the Heliocentris Fuel Cells. It is recommended that this document be
read carefully and completely before attempting to use the fuel cells. Following the
proper directions will ensure that the fuel cell membrane is not damaged during use in
the classroom.
The Parts of the Heliocentris Fuel Cell
1.
2.
3.
4.
5.
6.
7.
8.
Water reservoir – Hydrogen side
Storage cylinder – Hydrogen side
Hydrogen side stopper
Storage cylinder – Oxygen side
(hidden)
Banana jack – negative terminal
Protective diode
Banana jack – positive terminal
Water reservoir – oxygen side
Preparing the Fuel Cell for Use
1. Place the fuel cell upside down on a flat surface. In this placement the numbers
will be upside down and the negative (black) terminal will be on top.
2. Remove the stoppers from both the oxygen and hydrogen storage cylinders.
3. With distilled water, fill both storage cylinders to the top of the small tubes in the
center.
a. Note: Failure to use any liquid other than distilled water will result in
permanent damage to the proton exchange membrane (PEM).
© 2012 Project Lead The Way, Inc.
Principles Of Engineering Fuel Cell User Guide – Page 1
4. Tap the fuel cell lightly. This causes water to flow into the area surrounding the
proton exchange membrane (PEM).
5. Be sure to have towels nearby, because water will spill on the tables during this
step. Add more water until it starts to overflow into the small tubes in the center.
6. Put the stoppers back onto the cylinders. Make sure no air bubbles larger than
0.5mL are trapped inside.
7. If the membrane has not been used in a while and is dried out, allow it to soak for
about 10 minutes before attempting to charge the fuel cell.
8. Turn the fuel cell right side up.
Powering the Fuel Cell (Electrolysis)
Solar Panel as a Power Source
1. When powering the fuel cell, a solar panel in combination with a light source
can be used as the power source.

Using the sun as a power source is only recommended on a very sunny
day. This may take significantly longer to produce enough hydrogen and
oxygen to power the fuel cell.

A good source of indoor light is a 100-120 Watt Parabolic Aluminized
Reflector (PAR) light bulb.

Warning: Failure to follow guidelines regarding the light source could
result in malfunction or permanent damage to the solar cells.
© 2012 Project Lead The Way, Inc.
Principles Of Engineering Fuel Cell User Guide – Page 2
o Use light sources with a maximum power of 120W or less.
o Keep the light source at least 8 inches away from the solar panel.
o Do not concentrate the light with a reflector.
2. Connect the solar panel and the fuel cell as shown. The diagram below
illustrates the necessary setup for separating hydrogen and oxygen in the fuel
cell.

The positive terminals on both the solar panel (1) and fuel cell (3) are
connected by a conducting wire.

The negative terminals on both the solar panel (2) and fuel cell (4) are
connected by a conducting wire.
3. The formation of gas should begin immediately in both storage cylinders.
4. Once gas begins to bubble up from the small tube on the hydrogen side, the
fuel cell is fully charged. The light source can be turned off at this time.

For optimal performance, continue producing gas until the oxygen storage
cylinder has also been completely filled. An endpoint is reached when gas
begins to bubble up from the small tube on the oxygen side.
© 2012 Project Lead The Way, Inc.
Principles Of Engineering Fuel Cell User Guide – Page 3
Alternative Power Sources
Other power sources can be used to power the fuel cell, but this should be done
with caution. Failure to power the fuel cell according to the following guidelines
will result in permanent damage to the PEM. Over time, the fuel cell may lose its
functionality.

Do not allow currents more than 500 mA to flow through the fuel cell.

Electrical connections are the same as when using a solar panel. Connect
the positive terminal of the power source to the positive terminal of the fuel
cell with a conducting wire. Connect the negative terminal of the power
source to the negative terminal of the fuel cell with a conducting wire.
Examples of Alternative Power Sources

A current limiting DC power supply set to a maximum current below 500
mA and maximum voltage of 2 V.
1. Prior to connecting the fuel cell to the power supply, set the voltage
limit to 2 V and the current limit to 0 A.
2. Connect the positive terminal of the power supply to the positive
terminal of the fuel cell. Connect the negative terminal of the power
supply to the negative terminal of the fuel cell.
3. Gradually increase the current limit until it reaches 0.4-0.45 A, which is
safely below the 0.5A threshold. Gas should be produced immediately.

A different solar panel with the same current / voltage limits.

Two solar panels connected in parallel, as long as the 500 mA current limit
is not exceeded.

Hand-crank generator, as long as the 500 mA current limit is not
exceeded.
Fuel Cell as a Power Source
Failure to follow these warnings will result in irreversible deterioration of the PEM.


DO NOT short circuit the fuel cell. This will result in irreversible
deterioration of the PEM. A 10 Ω resistor in the circuit will prevent a short
circuit.
Do not allow current flowing out of the fuel cell to exceed 500 mA.
© 2012 Project Lead The Way, Inc.
Principles Of Engineering Fuel Cell User Guide – Page 4
Fuel Cell Storage
1. Remove stoppers and pour out all remaining water. Storing the fuel cell with
water in it will result in deterioration of the fuel cell.
2. Allow the fuel cell to dry completely.
3. To ensure that the PEM is allowed to dry fully, do not replace the stoppers prior
to storage.
4. Store the components at temperatures between 10–35 °C (50–95 °F).
© 2012 Project Lead The Way, Inc.
Principles Of Engineering Fuel Cell User Guide – Page 5
Specifications
Solar Panel
Characteristics
Value
Operating Temperature
10–65 °C (50–149 °F)
Length / width / height
52 mm × 70 mm × 130 mm
(2.04" × 2.8" × 5.11“)
Weight
60 g
With incident power of
1000 W/m2 at 25 °C (77°F):
Open circuit voltage
2.8 V
Short circuit current
250 mA
Operating current
200 mA (with 10 Ω load)
Operating voltage
1.4–1.6 V
Fuel Cell
Characteristics
Value
Length / width / height
70 mm × 90 mm × 80 mm
(2.75" × 3.54" × 3.14“)
Weight (unfilled)
140 g (2.1 oz)
Operating temperature
10–40 °C (50–104 °F)
Storage temperature
5–40 °C (41–104 °F)
Gas storage
2 × 15 mL
Electrolyzer operation
Working voltage
1.4–2 V
Current
0–500 mA
Rate of hydrogen production,
maximum
3.5 mL / min
Fuel cell operation
Operating voltage
0.5–0.9 V
Operating current
500 mA
Operating power
250 mW
© 2012 Project Lead The Way, Inc.
Principles Of Engineering Fuel Cell User Guide – Page 6