Bump... I also bought 2 cheap batteries for Omnia 7, and had the same problem, although it works ok, when you plug in the charger (or microUSB on PC), after 3-4 seconds the phone reboots. and then boots again, and instantly reboots...leading to an endless booting-rebooting loop. When you disconnect the cable, it's boots ok.
The batteries I got were marked 'Made in China' (made in Korea for the original). Also they had a (slightly) different P/N: EB504465VB (chinese) vs EB504465VU (original)
I have tried to charge the battery when the phone is in Download mode. It works, but I'm afraid that the constant image of the bootloader may burn in the Omnia7 AmoLED screen.
Has anyone found any decent source of replacement batteries for Omnia7 (apart from Mugen, that is very pricey)?