>I'm wondering if you can still use a tripod with the battery
>grip.

Yepp, you absolutely can! But if you use a heavy lens without tripodmount, the setup can have a little more flex to it than without a grip that may compromise the stability, and the result will then be dependent on the shutter speed, wind or other motion from the tripod. In either case, I would use a remote of some kind, wired, IR or radio for any pictures on tripod. In fact, I would do that in any case, with or without the grip!

/Timmy