Hi Danny,
* Double check to see if your new parts are good, make sure there are no signs that the ipad is not on other than seeing nothing.
* It is possible that you may have damaged a couple of components around a connector, Please take a couple of high resolution, focused photos of the battery connector.
* Other than that possibly the flex cable for the charging port, make sure its seated, and there is no physical damage. If you have access to a replacement I would try that.
Good luck