Well, it has to fit in the space. CRxxyy denotes the size of the battery, where xx is the diameter and y.y is the height, in those pesky metric units. So for example a cr2032 is 20 mm in diameter and 3.2 mm tall. For the metroid cart, this should just work right away. Of coure, you need to respect the polarity, however.

For the bleepbloop cart things get a little bit trickier, since it was not designed to use a CR2032 battery. You might even need a smaller size, say a CR1632. You'll want to solder one of the sides to a pad for mechanical robustness. For this, you'll probably want to connect the + tab to the bottommost terminal. However, only the top terminal (of the two soldered to the holder) is actually connected electrically to the rest of the circuit on bleepbloops. The other one is just an island pad. So you'd need to make a connection between the two pads using a thin wire. And you'd also need to connect the negative terminal of the battery to any ground point on the board using a jumper wire. For example the on in the microcontroller programming port. You also need to put some form of isolation around or under the battery to stop it form shorting to other things on the board. Heatshrink is not recommended, as the battery is sensitive to heat. Or at least be careful if you use it. PHEW.

Oh, or...
http://uk.rs-online.com/web/p/battery-h … s/2197954/

Thanks nitro I will try a cr2032. will that work in place of 1616, if so i will just get  one also for my metroid 2 cart?

Ohhhh, that's what he means. Yeah, the one I listed probably won't work then. My bad.

arfink: Not that. The bleepbloop carts came with a sleeve which was ust a metal part sitting over the battery. See the image below. The advantage of that compared to a more traditional holder is the low profile. However, this also means the PCB needs to be designed for this holder since you need to solder the holder on both sides, and the battery needs to make contact with the board on the bottom side. You can't just put this type of holder in a game cartridge. Nor would you need to. The batteries typically used in game carts are big enough to last 10+ years. As for replacing the sleeve, failing to find the right component, you might just replace it with CR2032 battery instead, assuming you can make it fit.inside the case.

If you're looking for a different mounting arrangement, go on Digikey and look up 16mm coin battery holders. The 1616 is close to the same thickness as the 1612, 1620, and 1632, so they're usually lumped together with just different sized spring arms.

You mean this?

http://www.digikey.com/scripts/dksearch … ageSize=25

Battery sleeve? Please elaborate!

I have a bleepbloop cart that needs a new battery sleeve. i would also like to install one in my metroid 2 cart. where do i find this part?