Yes, the tin is highly conductive. Do you have a multimeter? You can always check things like that with a multimeter. I think the best way is to use a small piece of wood cut to size, to install your battery terminals to. You can just screw them in to the wood with a tiny screw, or glue them. Also what I have done is fill the space with hot glue (also non conductive) and trim it to size with a sharp knife once it has cooled.
There are many ways to do it but one constant is you really should check your work with a multimeter for shorts. Never just shove batteries in a mod you made without checking for shorts. Of course you probably already know that
-Sam
Electrician's tape I put around the edges of my tin mods and bottom, anywhere a wire or connector touches, then hide it a material![]()
if you can put a block of wood or something inside of it to stablize it as you dril through that will help. I'm guessin the drill bit caught and torqued the metal right?
Other trick is fast drill, slow even pressure.
For drilling through the tin, use an awl or nail to get a starter hole and use an 11/32" or smaller drill bit to drill the hole for the connector. What I usually do is start smaller than the connector and then enlarge the hole with a cone-shaped stone grinder bit so that the connector is as snug as possible. I highly recommend the pilot-tipped dewalt drill bit set from home depot which do a decent job of preventing the bit from walking, but a little pilot hole is still a good idea. http://www.homedepot.com/h_d1/N-5yc...1&keyword=titanium&storeId=10051#.UHox3d1lQbM
Step bits also work nicely but are usually $30+. Well worth it if you often need to drill holes into metal, dont leave for work without ithttp://www.homedepot.com/h_d1/N-5yc...0053&langId=-1&keyword=step+bit&storeId=10051
Other than fast drill and slow even pressure, try and drill as straight as possible. "Let the drill do the work" is what I was told when I was a young electrician's helper. A good quality bit that's used for its intended purpose will save frustration/money.