Funny that you can't buy them anywhere! You can easily find the kit you need but without battery or charger (Humminbird PTC UNB 2). Make sure you get the "2" for your Helix if you go that route as this will have the correct shuttle for mounting. You can find the older version just about anywhere but I'm not sure if it could be easily modified to fit the Helix. You really just need to accomplish 3 things before using this unit on the ice:
1: Put it into a case or shuttle to make it portable. Buying Humminbird's cloth case ($50) and building your own shuttle is not a bad idea. People have used all kinds of things to build their own. It only needs to hold the sonar unit and a battery. Here's mine (Husky cooler), along with more ideas throughout the thread:
http://www.iceshanty.com/ice_fishing/index.php?topic=189700.msg3549306#msg35493062: Hook up a battery. Most guys use the 7AH to 9AH sealed lead acid batteries that can be had for around $20. Lithium batteries are nice but cost around $100. The wiring is very simple but feel free to message me if you need a hand. I bought a Battery Tender Jr to charge mine with so I wired the charging cord in as well. Makes it easy to charge.
3: Get your transducer to point down at the fish. I rigged my DI transducer so I could use it through the ice and it works well for me. You can buy the ice transducer from Humminbird for around $80-90 and it'll be easy to drop down your hole. Keep in mind that ice transducers do not have DI or SI capability so those features won't be accessible with the ice 'ducer.
If you want simple I'd buy the ice transducer and Humminbird PTC UNB 2 case (this is the newer case for the Helix, but it doesn't come with battery or charger. Easy to find on Google.) Then order a battery from Cabela's or somewhere (7AH sealed lead acid battery). Grab a Battery Tender Jr and you're all set. Of course this will not be the cheapest route. If you want cheap look more closely at the setups in the thread I linked to. Good luck, these are awesome machines on the ice!
