Snowpulse avalanche airbag backpacks (what are these?) were the first to provide a user refillable air cylinder. This feature allows you to refill your spent cylinder and get back on the slopes without delay or shipping costs, and if you don’t want to refill it yourself, you can always exchange it for a full one through the mail. My fiance has had a Snowpulse for a couple of years and we’ve refilled it several times (no she didn’t use it in an avalanche, just for regular tests). Snowpulse is coming out with a new system (2.0) next season, which is similar to that described below, but more user friendly. While the current system may appear complex, once you’re used to it and have a good place to get the compressed air, you can do a refill quite easily. Old 1.0 or new 2.0 system, below will give you an idea of what’s involved in a refill. For our reports on this process for other brands, please see our index of Avalanche Airbag blog posts.
You’re done with the assembly part, now the cylinder is ready to be filled. This can be done at one of four places: some licensed retailers, a paintball shop, a dive shop, or a fire station. You cannot do this at the gas station or on a construction compressor as you need 3000 psi of air! The head comes with a paintball fill fitting, so that’s the easiest route, but beware that paintball shops may not be good about keeping their air dry, which is very important. Dive shops require a paintball to SCUBA adaptor, have dry air, and should be very willing to fill your cylinder in the slow winter months if they are open. Fire stations require a paintball to SCBA adaptor and also have dry air. My experience is limited to fire stations, which is a great option as they should do it for free, every town has one, and they’re often open 24/7. However, it’s a mixed bag as far as how willing they will be to do it. Some stations will even change their minds (Aspen would do it a few years ago, but not anymore), so be sure to be courteous and perhaps consider a donation of some form (although this should be a free community service- you pay taxes right?) to keep them happy. A fifth option could be a ski patrol that uses the packs, but I haven’t tried and am not sure how involved in this they would want to get.
Whoever you have do it, have them fill the cylinder slowly (to avoid overheating) to 3000psi. Let them know that there is a check valve in the cylinder assembly, so when they unhook the adaptor, the air will stay in (I’ve had some confusion with that one). The cylinder will be hot, so you must cool the cylinder to room temp and then top it off. The reason for this is that gas expands when it is hot, so when the cylinder cools, the volume will drop. The cylinder gauge must read 3000 psi at room temperature. A water or snow bath will work, or just wait a couple hours. If you over fill the cylinder, there is no bleed valve, so to release some air you’ll have to release all of it.
Bonus: For air travel, you unfortunately cannot bring a filled cylinder aboard. You must remove the cylinder head from the cylinder body so that security can look inside. Make sure to take these apart before you get to the airport, and keep them that way until you reach your destination. Goes without saying that this should only be done with an empty cylinder! The head should screw off easily by hand, if you encounter resistence, a wrench may be necessary (some early Snowpulses have Loctite on the threads). When you reach your destination, screw the head back on by hand, not too tight and be careful to not cross the threads. You will then have to fill it, so be sure to have an idea on how you will do this wherever you end up. For more on flying, see my airbag overview.
Also, be sure to check out Snowpulse’s videos.