The Galaxy S3 battery is fully compatible with the S4, despite the different sizing. The thickness and height are the same, with a small difference in width. This only affects the battery capacity (i.e. run time) but otherwise works perfectly with the phone. I have several spare S3 batteries and comfortably use them while waiting for the S4 accessories to drop in price. Please watch the full video and click "Like" if this helped you!
![](https://s2.save4k.ru/pic/vb2hM-ctkpA/maxresdefault.jpg)