Questions about Body+

The batteries required are 4 ordinary 1.5V alkaline batteries (AAA). charging via USB is not possible. Of course, you can also use rechargeable batteries. For example, the following product (charger incl. batteries): Panasonic Eneloop Basic Charger incl. 1x4 AAA Micro batteries (battery + charger, AAA, 750mAh, 4pcs.)

Yes, my Fitbit app shows the weight and other measurements that the Body+ took. I had to authorize this connection. Fitbit will download the data from Withings. You have to have accounts with both.