SNES battery replacement oddity

[Tithis]

I recently got a SNES along with a few games and plan to replace the batteries in them. The first one I replaced the battery in was Super Mario World. When I went to try the game it still had saves on it. I removed the battery and the game still has the old saves and is still capable of making saves. As such I can't really be sure if I did everything correctly or not.

How long should the saves hold without the battery? I want to know so I can test if the battery replacement was truly successful. I want to be sure I did it right before I replace the battery in LttP and Harvestmoon.

[onemanfilmcrew]

Sometimes when you replace a battery, weird things can happen. I replaced a dead battery in the original Phantasy Star, and not only did the game save perfectly, but about every twenty minutes or so I would find a Silver Fang at the bottom of my inventory (which was really nice because it's the best weapon for one of the characters, and could be sold for a boatload of mesta).

[cyborc]

I replaced several batteries recently, and I found that if you swap the batteries quickly the saves will (usually) still be on the new battery.

I'm not really sure what the timeframe is because I had trouble desoldering one of the legs on one of the batteries so it took a while, and the saves were wiped when I put the new battery in.

[ryanstein]

You probably have a good reason for it, but forgive me if I ask the obvious question: why are you replacing batteries in games where the old batteries are still functioning?

[Tithis]

I'm replacing them mostly for peace of mind. I like knowing that I shouldn't have any problems with dead batteries and loosing saves in the future.

[Ziggy]

Definitely replace them! I got a FF2 cart a year or so ago. There was still saves on the cart. I played about half way through the game before the cart lost my save data, AND restored the data that was on the cart when I got it! Weird stuff does indeed happen. It is my understanding that the CR2032 batteries become unstable when dying. This would explain why my old Sim City cart would some times loose saves, but still be able to keep them.

Any way, because of FF2 I will put a new battery in any cart before I go ahead and play through the game, especially a long game like an RPG.

[opethfan]

Batteries are cheap. Why not replace all the batteries in all your games, just to be sure you won't have your day and game ruined when you least expect it?

[Ziggy]

Lol, the thought crossed my mind to just replace the batteries in ALL my carts. But then after I was thinking about it... that's a LOT of batteries! Some where around 200 for me.

Not to mention it's kinda a pain in the ass to replace them because of the way they're soldered in (those two stupid little clips) so doing 200 would take forever, and I'd probably break down and cry around cart # 50 lol. I have some battery holders from old motherboards, I was gonna see if it would fit inside the cart (it should).

Also, I figure, the longer I go before changing the battery the longer the battery will last for. So if I don't get around to playing Link to the Past for 2 or 3 more years, that's (theoretically) 2 or 3 more years longer the battery will last.

So in conclusion, that's why I decided to just replace a battery when I decide to play the game.