About those old Sega games with suicide batteries ...

I'm looking to buy some old Sega boards, namely Alien Storm and Golden Axe, and apparently those two come with suicide batteries. I have heard that they can be replaced, but I was wondering: How long will a fresh battery last in this case? I know its approximately 5 years with CPS-2 boards, but what about Sega System 16/ System 18 boards? Anybody know? Thanks.

(Or should I take the easy, but shady, way out and look for bootlegs of said games? )

If If remember correctly there are two different ways those batteries are employed. The first way employs using the battery in a custom cpu, when the battery dies the board will not work at all. The other way involves using the battery to power a decrytion table which in turn support the audio output of the game, when this battery dies video will still work but audio will not. The battery is a cr2030 or cr2032 and is physically encased in the custom chip it powers. The battery is hard to replace way more so then those on the C board of cps 1 games but if you did manage to do it will last about 4 to 5 years. The hacks to revive these games are not so good because they will produce numerous bugs if you can even get them to work at all. Your better off getting the boots.