Sega Saturn AA Battery holder

[opethfan]

Hi guys, I have a Model 2 Saturn, and I've been wanting to put a AA battery back in it to replace the CR2032. After all, 2600mAh or so beats 220mAh. Problem is, when I solder the wires to the battery terminal (see here: http://farm4.static.flickr.com/3208/301 ... d94f_o.jpg ), they don't stay. A mild tug and the solder comes right off. Underneath the board (can't find a pic) there are 2 solder points. I presume one is positive and one is negative but I don't wanna experiment with my beloved Saturn. Can anyone give advice regarding Saturn battery mods?

[Ziggy]

I'm pretty sure you can't use just one AA battery to replace the CR2032. The CR2032 is 3v, while a AA is only 1.5v, you would need two AA in series. Though I cannot comment if that would work either. Why use AA anyway? It's not like you have to change the CR2032 that often. I put in new one in my Saturn and it's lasted for at least 2 or 3 years now.

You're trying to solder wires to the battery holder tabs? If the solder isn't taking, it sounds like you're not using a solder with a flux core. You need flux or it'll never take. If you're trying to solder to a battery, that just wont ever happen. You need battery holders.



If you're trying to solder to the battery holder tabs, why not just remove the battery holder and solder the wires directly to the motherboard? I guess you could leave it on and just solder to the solder points on the underside of the board like you said. It's easy to find out which is positive and negative. Just look at the battery holder. Top of the CR2032 is positive and the bottom is negative. Just look at the holder to figure out which part of the battery touches what, then trace that back to the board. If you can't see it, then use a multimeter.

[Mindl3ss]

I'm pretty sure you can't use just one AA battery to replace the CR2032. The CR2032 is 3v, while a AA is only 1.5v, you would need two AA in series. Though I cannot comment if that would work either. Why use AA anyway? It's not like you have to change the CR2032 that often. I put in new one in my Saturn and it's lasted for at least 2 or 3 years now.

You're trying to solder wires to the battery holder tabs? If the solder isn't taking, it sounds like you're not using a solder with a flux core. You need flux or it'll never take. If you're trying to solder to a battery, that just wont ever happen. You need battery holders.



If you're trying to solder to the battery holder tabs, why not just remove the battery holder and solder the wires directly to the motherboard? I guess you could leave it on and just solder to the solder points on the underside of the board like you said. It's easy to find out which is positive and negative. Just look at the battery holder. Top of the CR2032 is positive and the bottom is negative. Just look at the holder to figure out which part of the battery touches what, then trace that back to the board. If you can't see it, then use a multimeter.

I would agree. Make sure you have a solder with a rosin core (flux), or, dab a little flux on the contacts you are soldering to.

If you are desoldering the old battery connector (will work better overall) make sure you clean it up well, and don't get it too hot, or you can take the leads off the board.

That video is excellent. I've watched it before.

I practice by just picking some simple boards at radio shack and a few cheap components, stick them on and solder away until you are comfortable

[opethfan]

Oh I know I need 2 AAs. I have a 2x AA battery holder. My buddy said I need flux, so he's probably right.

[gtmtnbiker]

I put in new one in my Saturn and it's lasted for at least 2 or 3 years now.

The Saturn has to be plugged in for the entire time (powered off) for the battery to last that long, correct? If it's not plugged in, then the battery only lasts 1-2 months.

[Ziggy]

Well I don't keep my Saturn plugged in.

[jeffro11]

I put in new one in my Saturn and it's lasted for at least 2 or 3 years now.

The Saturn has to be plugged in for the entire time (powered off) for the battery to last that long, correct? If it's not plugged in, then the battery only lasts 1-2 months.

Sorry to say but this is totally false. The amount of current needed to keep the SRAM from erasing the data is so minimal it would take years for the battery to drain.

[gtmtnbiker]

Sorry to say but this is totally false. The amount of current needed to keep the SRAM from erasing the data is so minimal it would take years for the battery to drain.

Check out this Sega Saturn battery FAQ found over at assemblergames.com:

http://www.assemblergames.com/forums/sh ... php?t=9053

-------------------------
*************************
Sega Saturn 10 year battery FAQ
*************************
-------------------------
By ASSEMbler
Version 1.3

Disclaimer
------------------------
Sega Saturn battery life greatly varies by how often you
use the unit, how often you keep it plugged in, and temperature.
Battery life has been estimated in both normal use and unplugged terms.

Revision History
-------------------------
1.1Made it a lot more simple to understand and added pictures.
1.2 Removed time estimates until I can calculate for mAh consumed
by the sram.
1.3 Recalculated based on sega estimates per mah, average plugged and unplugged use.

It seems a lot of people have been talking about replacing their Saturn battery.
So I have decided to write a min FAQ as there's a big difference between picking batteries.

========
CONTENTS
========

I -GENERAL BATTERY INFO
-------------------------
1.1 What is the Saturn Battery for?
1.2 What kind of battery does it use?
1.3 All batteries are not equal.
1.4 Battery power and life, mAh.
i. How much power?
1.5 The CR2032 ranking as compared to the SEGA standard 220mAh battery.
A. Bulk or generics
B. Store or name brand
1.6 Extreme capacity mods
A.CR123A extreme
B.CRV3
C.Military batteries, or OVERKILL
1.7 Vendors and Links.


*************************
I. GENERAL BATTERY INFO
*************************

1.1 What is a Saturn battery for?
------------------------

From the SEGA support site:

* The Lithium battery powers the Saturn's system memory.
* If you have had your Saturn for a while: The average life of the Lithium battery in the Sega
Saturn is one to two years. If you have had the Saturn for this amount of time, and had no
problems saving games until now, then the problem may be lack of internal memory space
or the need to replace the battery with a new one.

However what Sega fails to tell you is that they expect you to keep the unit plugged in
most of the time.

1.2 What kind of battery does it use?
------------------------

The Saturn uses a simple CR2032 battery to system setting and game saves.

1.3 All batteries are not equal.
------------------------

Q: Why does my Saturn eat batteries so fast? I just replaced it a few months ago and it's dead again!
A: CR2032 batteries are like any producible item; you can cut corners or skimp. As an example,
all of you have had cheap cola drinks, and quality ones. Just because they have the same name
doesn't mean they are of the same quality.
B. The Sega Saturn SRAM uses a lot of voltage compared to modern SRAM.

1.4 Battery power and life.
------------------------

The CR2032 battery used in the Saturn is a lithium battery.

(Do not confuse lithium batteries with lithium-ion rechargeable (Li-on) batteries. Do not use rechargeable batteries in the
Saturn as rechargeable batteries lose about 10-15% of their capacity every 30 days without use.)

The formulas used to make lithium batteries vary, and with it battery life. Cheap batteries are just that, cheap. They
have poor chemical properties and don't last very long.

Lithium can be partnered with many different chemicals for different life spans and power capacity, and that is the key
in picking the right battery.

Any decent lithium battery has a shelf life of about ten years. This does not mean you can run it for ten years.

i. How much power?

Capacity is quoted in 'mAh' or 'thousandths of an Amp x 1 hour. It indicates the current that the battery could supply
if it was going to take an hour to run out. It follows that if you discharge the battery at half the rate then it will last twice as long.

We are aiming for the battery with the highest "mAh" we can get without spending a large sum on exotic batteries.
However, for the extreme or modder type, I will go into detail on these exotics.

1.5 Choosing a battery.
------------------------

The CR2032 is a button type battery. Given its size it has limits to capacity. However,
through superior chemistry, we can get batteries in that size with superior life compared
to what you get from eBay, or a walk in shop.

The CR2032 ranking as compared to the SEGA standard 220mAh battery.

A. Bulk or generics
B. Store or name brand
C. High capacity
D. Small MFG - High quality hobbyist.
E. Extreme capacity mods.

A. Bulk or Generics
------------------------
"Bulk" or generic batteries are found on eBay, usually in large lots. They seem like a good deal,
but they really have inferior capacity. Expect 50-70mAh. YES ONLY 70mAh. Cheap and usually very old
chinese garbage or old military surplus that has 1/2 charge left in it.
Sometimes even alkaline passed off as lithium. Beware of counterfeits.

This kind of battery is what gives people the idea that changing the Saturn battery is pointless.

This would give a life of about four to six months with normal use.
This would give a life of about six days unplugged.

B. Store or name brand.
------------------------
The names don't really mater so much as these batteries usually never go above 220mAh.
Think of this as a standard replacement. But it will only last ONE to two years. Sega stated one to two.
(However this is an average based on the unitl being plugged in percentage of the time.)

MAXELL: 220mAh
PANASONIC: 220mAh
SANYO: 220mAh
SONY: 220mAh
ULTRALAST: 220mAh
ENERGIZER: 225mAh
DURACELL: 230mAh
KODAK: 230mAh
VARTA: 230mAh

This would give a life of about one to two years with normal use.
This would give a life of about ninteen days unplugged.

1.6. EXTREME CAPACITY MODS.
------------------------
So you're not content for two meager years of battery life.
(This should give you a

A.CR123A
B.CRV3
C.SAFT

Extreme capacity batteries will not fit into the coin battery slot on your Saturn.
You'll either have to make a dummy coin or directly wire a battery or battery holder to the motherboard.
However, for the average person this is easy to do.

A. CR123A
----------------------
CR123A batteries are small canister style cells that have a much higher capacity than a button style could
ever hope to have.

You can get these fairly cheaply and have outstanding capacities.
KODAK 1550mAh
VARTA 1600mAh

This would give a life of about six to seven years with normal use.
This would give a life of about 130 days unplugged.

B.CRV3
---------------------
Pretty much a double CR123A so you'll have to wire it up like in the diagram.

KODAK 3200mAh
VARTA 3300mAh

or if it's easier to understand

This would be the best route. Given the 10% gradual loss over ten years with lithium,
the CRV3 provides a healthy 297mAh even in it's last year. Far more than the 220mAh
battery that came stock ever provided new.

This would give a life of about ten years with normal use, this is limited by the lifespan of lithium batteries (10 years).
This would give a life of about 260 days unplugged taking into account the power curves batteries have when being discharged.

The FAQ implies that the Saturn SRAM consumes more power than other SRAM. It also says that you can make the battery last longer by having the system plugged in. Lastly, the type/brand of battery makes a difference in how long it lasts.

[Ziggy]

I'm pretty tired, but I don't see where it says that. All I see about plugging it in is "However what Sega fails to tell you is that they expect you to keep the unit plugged in
most of the time." Doesn't say that plugging it in makes it last longer. And if it does, I would assume it to be wrong information. But anyways, like I said, I keep my Saturn unplugged all the time. Battery has lasted a while now, and it wasn't even a new battery when I put it in there. I pretty sure it's a battery I took out of an old Pentium 3 computer.

But of course the type and brand matter. I've been trying to stress this for a while now. I've gotten cheap CR2032's that tested below 3v straight out of the package. A new battery should be like 3.08v or some where around there.

[opethfan]

Yeah, I contributed to that thread a few weeks back, asking if the system draws any power when turned off. The consensus was that it doesn't. I'm gonna try soldering to the bottom with the battery holder, it won't damage it if I get the polarity wrong, will it?