As you may know, the Sega Dreamcast was outfitted with a rechargable ML2020 Lithium battery. Released in 1998, the console (and battery) are now 22 years old.
It’s not surprising then, that the battery in your console probably won’t take a charge any longer, and you’ll be asked to input a date and time every time you boot it up.
There are two easy solutions
When fixing the battery in your Dreamcast, there are two methods to consider.
Method 1: Install a new rechargable Lithium battery
Method 2: Remove the charging capabilities, and install a non-recharagble Lithium battery
Method 1 is actually slightly easier to do, but if you’re like me and tend to play your consoles in short bursts ( < 1hour ), then you may find that even with a fresh rechargable installed you still get asked for date and time, due to the battery not having enough charge.
Note: If you decide to go this route, you must use an ML2020 or ML2032 which need around 3.2v to charge. If you use an LIR2032, it requires 4.2v to charge, and will not charge correctly.
Method 2 is a little more complicated, because you have to prevent the console from attempting to charge the non-rechargable battery, but it’s also very convinent (and cheap) to replace CR2032 batteries as they run out of juice. With this method, playtime doesn’t matter, and if you’re into old consoles, you’ve probably already got some CR2032 batteries lying around. If not, they are very cheap, usually about $0.40 each.
In this guide, I will show you how to perform Method 2, and with that knowledge you will be set up to do whichever method you desire.
Parts List
| Item | Quantity |
|---|---|
| Vertical 2025/2032 Battery Holder | 1 |
| CR2032 Battery | 1 |
| BAT85S Schottky Diode | 1 |
Tool List
- Phillips Head Screwdriver
- Soldering Iron
- Solder Flux
- Solder Braid/Wick
- Solder
- Flush Cutters
Step 1: Disassembly
Remove the modem from the side of your dreamcast by pressing in gently on the tab at the bottom and pulling outwards towards the side.
Then, remove the 4 screws holding the top case on.
Next, unplug the fan, and remove the 4 screws that hold in the controller ports. Unplug the ribbon cable and remove the controller PCB from the case. This is all you’ll need, so set the case and remainder of the Dreamcast aside.
Step 2: Remove the old battery
Apply some flux and fresh solder to the old battery, and remove it with your solder wick. Don’t force it and take your time, and it should come out easily. Alternatively, you can snip the legs off it, and use your soldering iron and some tweezers to remove each leg individually.
Step 3: Install the diode
In order to ensure that the dreamcast does not attempt to charge our non-rechargable battery, we need to install a diode in-line with the resisor to prevent the charge from reaching the battery. If you’re installing a rechargable battery, skip this step.
Clip the leg of the resistor as shown in the photo, then use your soldering iron and wick to remove the leg that you cut off.
Next, have a look at your diode. Make sure you’re installing it with the cathode (black stripe) facing downwards! If you install it the other way, it will do nothing.
Prep your diode by cutting the anode leg short, applying flux and tinning the end of it with fresh solder. Then you can insert the cathode leg into the hole where the resistor went, and solder it into place on the resistor, and the PCB.
Step 4: Install new battery holder
Install the battery holder where the old battery used to be. If you bought the correct battery holder, it will fit right into place where the old battery was. Use flux and solder it into place.
That’s it! Install your new battery and assemble your Dreamcast the same way you disassembled it. Once you boot up your console for the first time, it will ask you for the date & time, and then you will be good to go!
Good luck, and I hope this simple how-to was a help to you.
If you have any questions or concerns, please comment below, and I’d be happy to help.
Thanks for reading.
I hope you enjoy what you find on my site, and I will do my best to keep the content flowing as long as I can. Please feel free to comment anywhere on the site, as I would love to hear from you.
– raskulous
Why are you thanking Voultar for this mod? This was known for a long time with references about this on forums gong back further than 2016. Voultar has NOTHING to do with this mod other than taking credit for it. DC Swat and Acid Mods both have threads about this mod long before little V took the credit.
I didn’t say he was the creator of the mod, and neither did he. I thanked him for the information, because I got it from his video on the topic.
He is claiming he came up with it.
Jan 13 2021 – Little V’s Twitter.
QUOTE
“FYI: If you’re sending a Dreamcast to someone to be HDMI modified and they tell you that they also offer a battery mod that they came up with after careful analysis that allows you to use a standard CR2032 battery which will yield A VERY long life, they’re lying. That was me.”
END QUOTE
I only watched the video, I don’t follow his socials at all. I simply thanked him for the informational video.
edit: Clearly Voultar has some haters in the communuty, and all the power to you if you want to call him out on his bullshit. That’s between you and him. Go reply to his twitter post or something.
I simply wrote a blog post to show the details of the battery installation, and I got the information from his video on the subject. If that’s not okay with you, then please take your hatred elsewhere.
Just because the mod existed on some esoteric forum that I wasn’t aware of doesn’t mean that I didn’t sit down with an oscilloscope, map out the charging schema of the Dreamcast’s ML-2032 battery and select properly spec a diode with just enough current leakage to make this viable.
Nice of you to troll, though. I’m pretty sure I know who this was, and this person later apologized to me for their behavior and admitted to being wrong.
How long does a CR2032 last for you? I’ve read everything from 10 days to 5 years… Former would be super impractical and make me stick to my ML2032, but id it really held out several years, I’d try this mod.
It works essentially the same as most computer motherboards that use a CR2032 for CMOS settings. It’s just a small voltage to keep the data in SRAM.
Typically a 10 year old motherboard will still have the original battery and be just fine.
Thanks for the reply! Have you actually tested this for a prolonged amount of time? Because as I said, I’ve been reading all sorts of reports, that apparently the DC draws way more current and therefore the battery depletes much faster than one would expect.
P.S: And the issue I am facing with my now ~3 yrs old ML2032: While the DC doesn’t nag me about time/date everytime I boot it up, it appears to lag behind if I keep it turned off for a couple of days/a week. That said, i feel that the ML2032 (3V) never kept the Time/Date for much longer than a week anyways.
I haven’t tested it for a prolonged amount of time, as I only performed the mod shortly before posting this article. I have been having motherboard troubles with my Dreamcast, and I only recently got it working again about 2 weeks ago.
I fired it up just now, and it has the date/time saved just fine, if that’s any consolation.
That said, it’s a pretty well-known mod in the community, and I’m sure there would be tons of reports of it not working if it was a useless mod.
I did the mod now, as the time was running behind again after a week of down-time with the ML2032 battery. I measured the ML2032 and its voltage was at around 1.2V, so it figures the clock would always desync… Guess it was just a very cheap make of rechargeable battery.
With the CL2032 installed I now measure the proper 3,25 V (3,24 after the diode), so I hope this solves the clock issues for good 🙂
Thanks for the great guide. Much prefer written guides to video guides!
I’m happy I was able to help! If you do the non-diode method, you must use an ML2032, but if you decided to put in the diode to stop the charging, you need a CR2032.
Basically, the ML is re-chargable, the CR is not.
Yep, just be wary of cheap rechargeable ML2032 batteries. As I said, mine never held out much longer than 1 week, even when I let the DC charge it for a whole night. After 1 week, the time would always be behind and at some point, if unused, the DC would completely lose time (as if no battery was inserted).
So I added the diode and installed a CR2032. Curious just how long this will last, before it’ll need replacing. 🙂
When doing Method 2 it’s best to remove the 13ohm resistor entirely since its sole purpose is to limit the charge current for the ML2020/ML2032 batteries.
If the resistor is kept, the CR2025/CR2032 battery’s current will be further limited thus reducing the battery’s lifespan in the Dreamcast.
Also, just about any small through hole Schottky diode will do fine for this mod.
I bought a modded Dreamcast off eBay with a battery mod. The battery included is an LIR2032. Is this a problem? If I play the Dreamcast regularly, it doesn’t ask me to put in the date or time. If I don’t play for a few weeks, then it prompts me to enter date and time again.
LIR is a rechargeable lithium ion battery, which is what the dreamcast came with. It’s not a problem to leave it like that, but it seems like your battery is no longer able to charge. I would recommend you follow my mod here and change it out for a replaceable battery instead.