Greetings qedded,
Let's troubleshoot the power issue you are having with your EOS R8 camera body. First, we would recommend using the official Canon charger when charging the battery. Please check for debris inside the battery compartment where the pins are located and check for debris on the metal contacts on the battery pack. You may use a dry microfiber cleaning cloth to wipe the contacts. In case the battery shows that it is fully charged, then it may be possible that the battery is no longer holding the capacity it once used to and may prevent the camera from turning on. You can try testing a new battery pack with the camera.
Otherwise, with the camera switched to the 'Off' position please remove the lens and the memory card from the camera. Make sure there are no other accessories attached to the camera body. Turn on the camera body only to see if it powers on. If the camera does power on, then let's turn off the camera and insert the memory card only. Turn the camera back on to see if it does power on. In case it doesn't, then it may be an issue with the memory card causing the camera to not power on. I would suggest testing a different memory card.
If the camera does turn on with the memory card, then let's turn off the camera and mount the lens back on to see if this is what is causing the power issue. If the camera does not turn on, then I would suggest testing a different lens on the camera. If other lenses work, then it may be an issue with the current lens you're trying to use.
In case the camera is still not powering on, then we would suggest on sending the EOS R8 camera to our facility for repair.
Canon U.S.A., Inc. has created a new online repair portal that allows you to set up service in a few simple steps. The repair portal gives you the ability to set up service for multiple pieces of equipment at once, and to receive a repair estimate in the majority of cases, depending on your model and issue. The portal also allows you to upload images or videos that will assist us in repairing your product. You can also select how you wish to be notified of the progress of your repair. The portal's service history section allows you to view all services that have been performed on any of your camera or video products since January 7, 2020.
Please follow the link below to access our online repair portal to arrange for service:
https://mycanon.usa.canon.com/signin
Instructions for Accessing and Using the Online Repair Portal.
You will need to access or create your My Canon Account.
If you already have a My Canon Account and your product is already registered, simply click on the “Get Repair Services” link on the left menu and follow the onscreen instructions to arrange for service for your product.
If you have a My Canon Account and your product is not registered, you must register your product first. Click on the “Get Repair Services” link on the left menu, then click on the “Register Product” link on the right. After your product is registered, click on the “Get Repair Service” link on the left menu and follow the onscreen instructions to arrange for service for your product.
If you do not have a My Canon Account, you will need to create one. After you create your account, click on the “Add Product” link to register your first product. After your product is registered, click on the “Get Repair Service” link on the left menu and follow the onscreen instructions to arrange for service for your product.
Once you have completed the repair request, you will have an opportunity to print a copy of the request for your records. This request form will also contain shipping instructions and an address label that you will attach to the outside of your shipping box when mailing your equipment for repair.
