[str8desifer]

Hi,
I found a site that has a couple of m3 gba expansion packs in stock. Being how the product is old, and the battery most likely dead, would i still be able to save my gba files using the real time save? Or is the real time save for ds only? I know that the battery can be swapped by soldering a new one, but I have no such skills. Reason I want it is for the rtc and action replay cheats for the gba. Don't really care about ds games as i have a dsi xl for that.

[DinohScene]

It doesn't have to be dead.

I recently bought a Kirby NES game in mint condition wich still had it's original battery + saved game.
Assuming the battery is more then 18 years old, it still works perfectly fine.

Why do people think batteries only last a few years ;s

How ever.
You could cellar tape a new battery in.
It maybe somewhat of an hillbilly solution but it does the job pretty well.
Still I'd recommend soldering it in.

[str8desifer]

DinohScene, on 24 January 2012 - 03:43 AM, said:

It doesn't have to be dead.

I recently bought a Kirby NES game in mint condition wich still had it's original battery + saved game.
Assuming the battery is more then 18 years old, it still works perfectly fine.

Why do people think batteries only last a few years ;s

How ever.
You could cellar tape a new battery in.
It maybe somewhat of an hillbilly solution but it does the job pretty well.
Still I'd recommend soldering it in.

Thanks for the reply. From reading around the forums, there are people that when they bought came with a dead battery.

[DinohScene]

Doesn't always have to be.

If the battery is dead, cellar tape a new one into it.
Maybe a hillbilly solution but it works.

[alphamule]

Another trick if you want to try it, is to do like I did with my old Gameboy and GB Color systems. I used something called a Mega Memory Card which even worked on the Gameboy Camera I got cheap off of eBay. It was $15 or so with S/H ~10 years ago. The memory card was around $10 if I remember right. If you're playing on a Gameboy Advance/SP, then you can use the multiboot cable to get the same ability. This assumes that someone has wrote the software and it's compatible with the saved game. It would be annoying though to have to constantly upload/download the save before/after a softboot, assuming that it'll even reboot without killing the power to the cart (there's ways to bypass this as well but it requires a hardware mod such as a capacitor+diode on the power rails). By the way, my eCube 1GB cards arrived so I can use the other solution: Just mod one cartridge to have a removable battery clip!

A small solar panel and super capacitor would work so long as you backed up your saved game data when done playing. In hindsight, the capacitor would only rarely have to be charged. In theory, a super cap can run the battery-backed SRAM for a long time. The reason no one does this is expense when they're trying to cut every nickel off the price of the cartridge's hardware. For a hobbyest, it's not a big difference. Here's an example of using a super capacitor for a similar project.

I looked up places to get a small and cheap super capacitor:

http://www.sparkfun.com/products/10317 3.3V, 0.2F, similar to 2032 lithium cell, $2

eBay item #150694457525: 5.5V, 0.22F, 3/8th inch diameter (smaller than dime), solder tabs, $3 for 2, another $1.50 for each additional pair. (75 cents to $1.50)

The 5.5V one would probably work better since it has a higher maximum charge(potential AKA voltage).

BTW: Here's a scary eBay item: 370578012182
3000 Farads = dangerous

Edited by alphamule, 25 January 2012 - 02:05 AM.

[str8desifer]

alphamule, on 25 January 2012 - 01:19 AM, said:

Another trick if you want to try it, is to do like I did with my old Gameboy and GB Color systems. I used something called a Mega Memory Card which even worked on the Gameboy Camera I got cheap off of eBay. It was $15 or so with S/H ~10 years ago. The memory card was around $10 if I remember right. If you're playing on a Gameboy Advance/SP, then you can use the multiboot cable to get the same ability. This assumes that someone has wrote the software and it's compatible with the saved game. It would be annoying though to have to constantly upload/download the save before/after a softboot, assuming that it'll even reboot without killing the power to the cart (there's ways to bypass this as well but it requires a hardware mod such as a capacitor+diode on the power rails). By the way, my eCube 1GB cards arrived so I can use the other solution: Just mod one cartridge to have a removable battery clip!

A small solar panel and super capacitor would work so long as you backed up your saved game data when done playing. In hindsight, the capacitor would only rarely have to be charged. In theory, a super cap can run the battery-backed SRAM for a long time. The reason no one does this is expense when they're trying to cut every nickel off the price of the cartridge's hardware. For a hobbyest, it's not a big difference. Here's an example of using a super capacitor for a similar project.

I looked up places to get a small and cheap super capacitor:

http://www.sparkfun.com/products/10317 3.3V, 0.2F, similar to 2032 lithium cell, $2

eBay item #150694457525: 5.5V, 0.22F, 3/8th inch diameter (smaller than dime), solder tabs, $3 for 2, another $1.50 for each additional pair. (75 cents to $1.50)

The 5.5V one would probably work better since it has a higher maximum charge(potential AKA voltage).

BTW: Here's a scary eBay item: 370578012182
3000 Farads = dangerous

Thanks for the links. I ordered the m3 with the gba expansion pack. I'll see how it goes.

[alphamule]

Awesome. Good luck with your cartridge!

The only thing with super capacitors that would hurt us is that they self-drain pretty damn fast. Even compared to a Nickel-Metal-Hydride cell such as 'rechargable AA batteries' you can get at a Wal-Mart or the like. We're talking at most days to fully drain. But the good news is that the RTC has virtually no impact on that time, which is hilarious!

A solar cell charging it up while you're awake would keep up the charge, in theory. I'd not trust it for my game progress, although an LED flashlight would be a great application of some of the larger super capacitors. Even 'just' 1 Farad is enough to run an LED at full brightness long enough to be useful. It sure beats batteries or having to use a magnetic/mechanical charger/generator. That 3rd link was a PITA to find, by the way. I was thinking that the ones I had back in the 1980s had a dynamo that you had to pump your fist to spin. They were the yellow/plastic ones but the brand name has long escaped me. Bah, that third link just talks about them. http://safetycentral...dynpumflas.html This is a more faithful reproduction. The flywheel makes it run a lot smoother and gives more currant than a LED would ever need.

Edited by alphamule, 25 January 2012 - 07:25 AM.

[Ajax]

I'm bumping this topic to let you guys know that installing a supercapacitor in place of a dead battery seems to actually work quite well.

The battery on my M3 GBA expansion cart died a year or two ago, so I replaced it with another battery, and when that one died a fairly short while later, I was pretty bummed, and figured that I would be forever doomed to have a cart that wouldn't hold sram. After reading this thread, I eventually decided that this super capacitor would work the best (this one is similar to one of the ones linked in this thread, but has the solder tabs in the same arangement as the original battery, making it really easy to solder in). Even though the capacitor was a lot smaller than I expected, and solder tabs were a bit closer together than the ones on the original battery, it was still a sinch to solder it in place, and shouldnt be too hard to do as long as you have had a little soldering experience.

One thing to note, however, is that these little super capacitors seem to take a long time to charge. I was getting errors for a quite a while before the card finally started booting games properly, so I suggest turning on your DS and letting the capacitor charge for 20-30 minutes (though honestly, I have no idea if the capacitor needed to charge, of if my cart was just being flakey).

Well anyway, I have no idea how this will turn out in the long run. I'm just happy to have my GBA expansion cart working again.

[yellowsnowcone]

Ajax, on 15 April 2012 - 08:44 AM, said:

One thing to note, however, is that these little super capacitors seem to take a long time to charge. I was getting errors for a quite a while before the card finally started booting games properly, so I suggest turning on your DS and letting the capacitor charge for 20-30 minutes (though honestly, I have no idea if the capacitor needed to charge, of if my cart was just being flakey).

Your cart's memory was probably working on near-threshold voltage, and draining the cap too fast, causing hard errors all over the place. High internal resistance makes for longer charge and slower discharge, which is what makes a supercapacitor useful. I don't know enough about the M3 GEP (I ended up getting a EZ IV) to say whether it will work better in the long run than a battery.

[Ajax]

The funny thing is that even when I had a dead battery (really dead, <0.5V), I could still load up roms and play just fine. the only problem would be that my sram would clear between power cycles making it impossible to retain saves (the M3 real firmware automatically writes saves to sdcard every power-on after playing a GBA game). However, when I had recently installed the capacitor (multimeter showed the charge to be ~2.6V), the DS would appear to freeze when loading roms onto the cart.

Well, initial tests show that the capacitor can retain sram for at least a couple hours after DS power off, and I am currently testing to see if it can reatain saves for >1day after DS power off. Though in actuality, as long as you quickly reboot your ds after playing a GBA game in order to get the M3 firmware to transfer sram to the SDcard, you should be fine.

...though now I need to fix my broken L button, anybody know of any decent sources for DS lite shoulder button switches?

[alphamule]

Llama?

[yellowsnowcone]

Ajax, on 17 April 2012 - 01:05 AM, said:

The funny thing is that even when I had a dead battery (really dead, <0.5V), I could still load up roms and play just fine. the only problem would be that my sram would clear between power cycles making it impossible to retain saves (the M3 real firmware automatically writes saves to sdcard every power-on after playing a GBA game).

That would be expected of a dead battery. While your DS is on, it should be primarily getting power from the DS, not the battery/supercap.

[Densetsu]

You should ask how_do_i_do_that directly. He's like, the resident expert on all things Slot-2.