It seems like it has been a while since anybody has posted about this topic, so I thought I would weigh in.
Eight Ball Champ uses the Bally 6803 Control Board and Pinitiech's 6116 NVRAM is advertised as a "Plug and Play" replacement of the battery and RAM modules.
Yesterday, I cut the battery from my Control Board and replaced the RAM chip with the 6116 NVRAM. At first, I didn't realize how much force it would take to get the pins seated. They are a nice, tight fit. This is probably a good thing since there is no locking mechanism to keep the chip in place.
I booted up EBC and... blank. I took the control board out and put it on a firm surface and finally applied enough pressure to get the pins to seat properly. My fault for improper installation. After putting the board back in, the machine immediately booted up with factory default settings.
The instructions that came with the NVRAM did not apply to my particular machine; I think the instructions were written for later models - the A button does nothing on EBC and I am not sure where I would be able to read "Feature Options" on a display. I just followed the programming instructions in my EBC manual and aside from a typo in my manual (register 27 is for sound options, not 28), everything works perfectly! I set it to free play, customized background sounds, reset the high score, and set number of balls per game within a few minutes. High Score and all customized settings work perfectly and there is no battery within 30 feet of my 6803 control board.
This is probably the best $20 (with shipping) mod that I can think of. 6803 Control Boards are becoming hard to find and there is no reason to risk damage from a battery failure. I have seen battery mod suggestions elsewhere, but this is so much simpler, more elegant, failsafe solution.
Final opinion: No brainer, 5-star replacement for Bally 6803 Control Boards.
I would consider using it for Williams System 9 or System 11 boards, but that requires that you de-solder your RAM chip from the board and replace it with a socket. There may also be jumper change(s) required. Sounds like quite a bit of work but may also be worth the effort if you are OK with DIY circuit board repair. Other battery mods would be easier, but you still end up with a battery connected to your control board with the other solutions that I have seen.