I have never replaced a battery in any of my NES cartridges and they all still save just fine.
I have never replaced a battery in any of my NES cartridges and they all still save just fine.
I have never replaced a battery in any of my NES cartridges and they all still save just fine.
Seriously though I was just talking with my friend about how we had to replace our Pokemon cart batteries yet our 35 year old NES games save just fine
it's cause pokemon games either use batteries with a quarter of the capacity or have an RTC which drains the battery really fast.
my R/B/Y carts still have their original saves
meanwhile my G/S/C ones have all crapped out
G/S/C has an RTC that drains that shit within a week.
How much current is needed to keep the SRAM alive? Assuming CMOS, wouldn't it theoretically be zero?
Yes. In theory you only need voltage.
But in reality there inevitably are leakages. No insulator is perfect, not to mention microscopic surface flows. That's why over time every battery will run dry.
in extremely low current cases like these, the battery dies mostly from its own internal resistance
CMOS chips only need a tiny amount of current to hold a transistor's state. Full power is only used to change states.
SRAM alone has basically no power consumption. The battery loses more power from external wear factors such as shock and corrosion than it does from normal operation pretty much, so the battery will basically last for an indeterminate but really fricking long time.
The only time a save battery ever really "reliably" dies is when it's used to power something else like an RTC module.
nor SRAM specifically but CMOS SRAM which was what NES cartridges as well as the RAM in the console itself was
until the '90s most more complex ICs were NMOS with CMOS being limited to simple components like logic chips and SRAM. it took some advances in manufacturing tech for CMOS to be universally used. mostly. yes, Intel did the 386 in CMOS since 1985 but they had the most cutting edge tech which not every chip fab had.
That was an important reason why the Mega Drive was the last 80s console and the SNES the first 90s one--the former had an NMOS chipset (at least in Model 1 MDs) while the latter used all CMOS chips.
I had to replace the one in my Zelda 1 cart. It would keep its save for a while but if you left it overnight it would erase everything.
Nintendo used various brands and makes of SRAM (in US carts normally always an 8k chip, Famicom ones had more variation) some of them drew more current than others
So you may have this happen.
>I never touch my NES cartridges so I just assume the saves are fine and working
This is you.
I'd be less worried about whether or not is saves and more worried about it spewing corrosive acid all over the PCB.
It's zinc-carbon and alkalines that leak.
NES cartridges use lithium batteries which don't leak.
I've seen enough destroyed carts to know otherwise.
Much more likely to be caused by the electrolytic leaking, not the battery.
>battery splooged all over the pcb
>"it's probably something else"
ok
pics or it didn't happen
Never seen a coin cell that leaked in my own projects or any videos I've seen.
Pics or it didn't happen.
like others said the RAM in NES carts are CMOS chips. the ROMs are usually CMOS as well but NMOS was sometimes used--you can tell these carts as they get noticeably warm when you've been running them a while. Nintendo's MMC mappers existed in both NMOS and CMOS versions.
My NES and SNES games all save fine.
The only batteries that have died on me were on Game Boy and Game Boy Color games
They all use batteries.
Green/Red/Blue use CR1616s
Yellow uses a CR2025
Silver/Gold/Crystal use CR2025s as well, but have an RTC chip that drains the battery really fast (like 10 years).
Given this, Yellow should have the longest lasting battery because it's big and has no RTC.
>(like 10 years)
GSC drain their battery in like 3-4 years, maybe a little longer for Crystal. I remember being 10 in like 2004 and doing the pen lighter trick to open my Silver cart and peel the battery off its tabs because the battery died.