The Dreamcast uses a soldered-in, rechargeable battery to store the console's date and time settings. The battery recharges whenever the console is powered on, takes about 2 hours to charge from empty to full, and should hold date and time settings for about 20 days. The batteries on most all Dreamcast consoles should be totally dead by now, so one can desolder the original battery and replace it with a plastic battery holder to allow easy replacement of a compatible battery, such as ML2032, in the future.
It is highly recommended NOT to use the LIR2032 battery type, as the Dreamcast does not output the voltage necessary for it to properly and fully recharge (LIR2032 are 3.6-3.7V batteries, rather than 3V). Instead, ML2020, ML2032, and ML2430 coin cells should be used, as they are all rechargeable 3V batteries of differing capacities and physical sizes per the following table:
diameter (mm) x height (mm)
|ML2020||45||20 x 2|||
|ML2032||65||20 x 3.2|||
|ML2430||100||24.5 x 3.0|||
Note that the ML2430 may be too large to fit with an appropriately-sized, vertical reusable battery holder, and as such ML2032 is the recommended replacement type. The vertically-oriented, soldered-in ML2430 type does fit, however, as some consoles came with those instead of the soldered-in ML2020 type.
- Standard vertical CR2032 battery holders such as these have the same footprint as the stock, soldered-in battery: https://console5.com/store/vertical-holder-for-2032-batteries.html
- ML2032 batteries can be found online from various places.
- Page 12, "Rechargeable Battery": https://archive.org/details/DreamCast_Instruction_Manual_2000_Sega_US/page/n11/mode/2up
- My R7 console did. --Moopthehedgehog