Does the new series X use the same battery packs as Xbox s

The Series X controllers available now uses the same official battery packs as the Xbox One and Series S controllers.

When you say you've tried New battery packs, was it a new battery pack designed for the Series S/X controllers? The Xbox One Venom battery packs won't fit the new controllers (Venom sell newer versions of these). The controller's much smaller size may have necessitated some minor changes?

But then if it;s the wrong battery pack, it shoudn't work with either controller ...the fact it works in one but not the other points to an issue with the second controller

The Xbox One Venom battery pack won't even fit in the Series X controller (or at least not without trimming bits off it)..as the OP can fit the pack with no issue, it suggests it's the right battery pack. Unless Venom have released more than one battery pack for the Series X?

No it's for the Xbox One X, the only difference is the clips on the battery cover, they are slightly further apart

Yeah, Venom cover this in their FAQs:

"Unfortunately due to the Series X/S controllers having a slightly smaller battery compartment we have had to create new batteries for our next gen products. Our Xbox One products will NOT be compatible, as with any other encased battery pack for Xbox One."

Hi,

1. It will work wired and wireless. You can only charge the battery while being wired if you have a battery pack installed. Regular AA re-chargeable batteries can not be charged during play. The official Xbox One X/S battery pack will be released November
   10, same as the console. As far as I know the controller does not come with a USB C cable, unless you are also purchasing an Xbox Series X/S console (cable is in the box). Yes, your PC will be able to charge/power an Xbox Series X controller.
2. Yes, once they run out you'll need to charge the battery. If you need to do this externally (AA batteries), you can connect the controller via USB and power the controller via the cable with no batteries installed. An official Microsoft fully charged battery
   is rated for around 30 hours. Re-chargeable AA batteries will vary.
3. Yes. You can use a Bluetooth USB dongle if your PC does not have BT built into the motherboard.
4. No. Windows 10 will already contain the necessary software to run your controller. There is an Xbox optional Wireless Adapter for Windows 10 available that uses its own wireless protocol and will allow some extra functionality such as headsets, chatpads,
   and the Xbox Stereo Adapter.