As a camera that shoots video, rather than a video camera, the Sony A7S II is restricted to the 29min 59 sec recording limit that is imposed in the EU. It’s an import duty thing apparently. Luckily this shouldn’t be of too much concern for most filmmakers, unless you are shooting live concert footage or long interview pieces.
As for the batteries, it takes the standard Sony NP-FW50 batteries that are used in the other A7 series cameras, and the current Sony CSCs, as well as the older NEX cameras. This means that there are plenty of them around, which is lucky as when shooting video the A7S II does get through them. Expect a battery to last for about 45mins recording. Luckily two are supplied in the box, but I’d suggest getting a couple more if you are doing a lot of shooting.
The camera can also be charged via micro USB on the side of the camera. This is useful when you are on the move. A USB battery pack is a good investment, and for about £30 you can pick up something that will charge a NP-FW50 about 4x over. That and you can charge in virtually any car or hotel room (use the socket in the back of the TV, but do so at your own risk!). It isn’t the quickest way to charge the batteries, but to keep topped up, or for an overnight charge, it is a very handy addition. Again, I would track down a dedicated charger if you are doing a lot of shooting.