A typical, single layer PEMC will look something like the photos below:

abThis one is conveniently labelled with the gases consumed/produced on that side. Note that each side has two ports for connecting hoses to. Unsurprisingly, the black and red terminals on the top are the negative and positive cell terminals respectively. Make sure you know which side is Hydrogen/negative and which side is Oxygen/positive – most common fuel cells can be damaged if you connect them the wrong way around. Also, as with a regular battery, a short circuit will burn through your fuel supply quickly and generate possibly damaging amounts of heat, so be careful. Some people like to put a high-current diode between the positive and negative terminals to soak up current if the cell is accidentally charged in reverse, but this is optional. Connect the diode’s cathode to the positive FC terminal, and the anode to the negative terminal if you decide you want to have the extra safety feature.

For the PEMFC to work, it needs high purity water on both sides of the cell. The membrane needs to be left for at least 10 minutes after adding the water so that it can soak in before you start using charging/discharging the cell. The water on the Oxygen-side will also be split into Hydrogen and Oxygen gases during charging, but a tiny amount of water produces a huge volume of gas.
Do not used tap water, mineral water, purified water, filtered water or any of that stuff – they’re all full of impurities that’ll slowly clog up the PEMFC and make it less efficient. Look for water that has been distilled instead, or if needed you can distill your own. I’ve got a big 10L container of steam distilled, ozonated reverse-osmosis treated water that’s about 100 times purer than typical bottled water. $6 at the supermarket, well worth the trouble of lugging it back to the car. Also good for watering bonsai trees.

Hopefully you’ll have been supplied with a few short pieces of rubber hose, a few hose stoppers, and a plastic syringe along with your fuel cell. If not you should probably find some gear along those lines (gardening supplies work well, i.e. automated sprinkler system hoses and fittings).
• Clean your hose, stoppers and syringe by flushing them with distilled water.
• Connect a piece of hose (at least 30mm, or 1inch) to each of the 4 ports on the FC.
• Fill your syringe with the distilled water.
• Insert the syringe into the lower hose attachment on the Hydrogen-side, and push the water into the cel until all the air is expelled and the water starts coming out of the top hose.
• Insert a stopper into the top hose, trying not to let any air back in.
• Pinch the lower hose with your fingers and pull the syringe out, replacing it with another stopper.
• Repeat the filling part for the Oxygen-side of the FC.

Now your PEMFC should be left to soak for at least 10 minutes. After that you can actually start using it like a battery, but since there’s nowhere for the accumulated gases to go the capacity will be pretty low, so the cell will charge and discharge quickly.
This next part may require some creative thinking on your part – where are you going to store the gases for the fuel cell? A few things to remember about your storage system ideas are that they must:
• Be sealed well enough to keep the gases trapped under slightly elevated pressures.
• Not be so restrictive that the fuel cell has trouble pushing the gas into the container.
• Have no problems with exposure to water, Oxygen or Hydrogen.

A common setup is to run the fuel cell gas hoses into two inverted jars/glasses/vials that are submersed inside a larger container and totally filled with distilled water. Oxygen and Hydrogen don’t dissolve in water very much, so when the gas flows out of the hose it’s trapped in the top of the inverted container. As more gas flows in, the water is pushed down into the larger container, so gas can be accumulated without a large increase in back pressure. Producing too much gas just causes the inverted container to overflow and bubble off into the air, so no worries there either. The main disadvantage of this setup is that you have to keep the storage arrangement upright, otherwise everything just spills out. Alternatively you can use the balloon system I developed for Mr. Lobster, which I haven’t had any trouble with.

Regardless of how you store your gases, make sure to once again wash everything with distilled water just to be safe. Also remember to keep your Oxygen and Hydrogen seperated – it’s a pretty explosive mix =)
Once your storage system is prepped you can hook up the lower hoses from the fuel cell to your storage tanks, and now you’re ready to go!