In system preferences/energy saver i checked Enabled Power nap while on battery power, and i start backing up to my TC and close the lid and this morning starts from where i let it last night...i am doing something wrong?
Have you tried using the power adapter to see if it does complete the backup in Power Nap while connected to power? It may be that TC wireless backups only work when connected to a power source.
If you check the Apple Support Forums you'll see that there are still many reported problems with Power Nap especially with MacBook Airs.