Long lasting cr2032 alternative for motherboard

[Kjelt]

Intro:
I always power up and shut down all equipment in the lab with heavy relays just as fire precaution and since energy has become quite expensive also to save a bit $.

Issue:
My pc's cr2032 battery goes empty within 10 months result in BIOS and clock setting each time. I have an Asus motherboard and the engineers thought it would be a great idea to put the batteryholder under the graphica card which takes me 22 minutes to replace.

Alternatives:
I purchased on aliexpress an empty cr2032 coin with undefined metal red and black wires badly soldered to them. Replaced the wires with decent 0.25mm2 copper Lapp cable and now I have the following alternatives and question:

NiMH two cells 2.5-2.9 V will it be enough?
        Three cells 3.6 - 4.2 V will it be too much?  Diode in series to drop the voltage?

CR123 Lithium expensive how long will that last?

Alkaline two cells: 2.6 - 3V  leakage issues?


What did YOU do or what would you choose?
Anyone know the voltage limits for the mainboard chip?

[Andy Chee]

If your CR2032 is being drained in 10 months, then there is something wrong with your motherboard.

(or you are purchasing poor quality CR2032 batteries from eBay)

[nctnico]

If your CR2032 is being drained in 10 months, then there is something wrong with your motherboard.

Agreed. A good quality CR2032 should last for about 10 years in a motherboard.

[squadchannel]

CMOS batteries for clock and settings data retention are normally not used when connected to the mains.
This is because even when the computer is turned off, it is not completely disconnected; it is still supplied with standby power, which is used to maintain the clock and to process when the power button is pressed.

When connected to the mains, the battery is automatically disconnected and operates on standby power. (This is an ambiguous term. It is actually similar, but different.)

I would expect it to hold up fine if left alone for 10 years or so, but if it consumes it after less than a year, is the bad motherboard, is the battery of poor quality, or is it a design problem? I wonder.

[coppice]

If your CR2032 is being drained in 10 months, then there is something wrong with your motherboard.

Agreed. A good quality CR2032 should last for about 10 years in a motherboard.

More specifically, the drain should be so low the lifetime is dominated by self leakage rather than the board's consumption. So, for a typical CR2032 you should expect a minimum of 10 years, even in a climate where the leakage is maximised. On the other hand, don't expect more than 15 years.

[wraper]

If your CR2032 is being drained in 10 months, then there is something wrong with your motherboard.

Agreed. A good quality CR2032 should last for about 10 years in a motherboard.

10 years is a little bit of a stretch in general IME, but it should last at least 5 years for sure.

[janoc]

CMOS batteries for clock and settings data retention are normally not used when connected to the mains.
This is because even when the computer is turned off, it is not completely disconnected; it is still supplied with standby power, which is used to maintain the clock and to process when the power button is pressed.

You have missed literally the first line:

I always power up and shut down all equipment in the lab with heavy relays just as fire precaution ...

So there is no standby power.

If your CR2032 is being drained in 10 months, then there is something wrong with your motherboard.

(or you are purchasing poor quality CR2032 batteries from eBay)

I have seen this problem with one of the Beelink mini-PCs that my mother has. The backup battery lasts there maybe a year. The motherboard is simply poorly designed and is drawing too much current from the battery.

[squadchannel]

CMOS batteries for clock and settings data retention are normally not used when connected to the mains.
This is because even when the computer is turned off, it is not completely disconnected; it is still supplied with standby power, which is used to maintain the clock and to process when the power button is pressed.

You have missed literally the first line:

If you replace it with a high quality battery and it still wears out, it's probably a bad design or a bad motherboard.
Dallas NVRAM, that guy has a 10 year retension.

[coppice]

If your CR2032 is being drained in 10 months, then there is something wrong with your motherboard.

Agreed. A good quality CR2032 should last for about 10 years in a motherboard.

10 years is a little bit of a stretch in general IME, but it should last at least 5 years for sure.

This can depend a lot on dirt. If a PCB collects a greasy film its surface can leak quite badly when moisture, dust and that grease work together. The electronics would be pretty badly designed to consume enough to keep the life down to 5 years.

[tridac]

The solution here is to fit an AA battery holder to the side of the case, then use a 3.6v Lithium Thionyl Chloride, (eg: Saft LS14500), and never have to replace it again. Use the same for some older test gear that uses those aweful nicad rechargeables, that end up leaking all over the board.

Sounds like you may have a hardware fault, but a larger battery might still help. Have you measured the current drain from the cell ?...

[wraper]

The solution here is to fit an AA battery holder to the side of the case, then use a 3.6v Lithium Thionyl Chloride, (eg: Saft LS14500), and never have to replace it again. Use the same for some older test gear that uses those aweful nicad rechargeables, that end up leaking all over the board.

Sounds like you may have a hardware fault, but a larger battery might still help. Have you measured the current drain from the cell ?...

If original CR2032 was of a good quality, LS14500 will last about 8 years.

[tridac]

Yes, and there are C and D size cells of that type as well, though the 14500 will probably outlive the pc anyway....

[MathWizard]

If your CR2032 is being drained in 10 months, then there is something wrong with your motherboard.

Agreed. A good quality CR2032 should last for about 10 years in a motherboard.

So how is that possible though, what semiconductor's have such low leakage currents ? I would have guessed just the PCB materials or device leakage currents would drain a battery way way quicker. Or some internal issues that batteries have.

I saw a cheap smoke detector once at a hardware store, that claimed it's battery would last ten years, and it wasn't mains powered. I didn't trust the claim. And usually there's some LED or test LED on a smoke detector, nevermind the buzzer. So yeah I'm sure it won;t last 10yrs if they are used at all.

[wraper]

If your CR2032 is being drained in 10 months, then there is something wrong with your motherboard.

Agreed. A good quality CR2032 should last for about 10 years in a motherboard.

So how is that possible though, what semiconductor's have such low leakage currents ? I would have guessed just the PCB materials or device leakage currents would drain a battery way way quicker. Or some internal issues that batteries have.

I saw a cheap smoke detector once at a hardware store, that claimed it's battery would last ten years, and it wasn't mains powered. I didn't trust the claim. And usually there's some LED or test LED on a smoke detector, nevermind the buzzer. So yeah I'm sure it won;t last 10yrs if they are used at all.

PCB leakage is less than insignificant (unless its surface is heavily contaminated). RTC/CMOS RAM drains a few uA at most. It it say drains 5uA, CR2032 should be good for 5 years.

[wraper]

And usually there's some LED or test LED on a smoke detector, nevermind the buzzer. So yeah I'm sure it won;t last 10yrs if they are used at all.

I don't know shit but they certainly lie 

[CatalinaWOW]

Finding and fixing a motherboard fault is hard, and probably expensive since replacement is probably the solution. 

One obvious solution would be to parallel your new connector with the existing one and then setting a maintenance schedule.  Just add battery replacement to filter cleaning and all the other things you should be doing.  With two batteries the interval should be well longer than a year, and as long as you don't take both out at once you won't have to redo bios settings, etc.

Save the brainpower for more interesting stuff.

[nctnico]

If your CR2032 is being drained in 10 months, then there is something wrong with your motherboard.

Agreed. A good quality CR2032 should last for about 10 years in a motherboard.

So how is that possible though, what semiconductor's have such low leakage currents ? I would have guessed just the PCB materials or device leakage currents would drain a battery way way quicker. Or some internal issues that batteries have.

Typically there is some kind of dual power setup using diodes so when the PC is powered, the CMOS gets power from the mains supply. If the reverse diode has a lot of leakage, then it could drain the battery. It is also possible the diode and/or CMOS backup chip got damaged due to ESD when changing the battery and are leaking a lot now. Some measurements on the motherboard should be able to reveal what is wrong with it

[coppice]

PCB leakage is less than insignificant (unless its surface is heavily contaminated). RTC/CMOS RAM drains a few uA at most. It it say drains 5uA, CR2032 should be good for 5 years.

The leakage of PCBs varies enormously. They are usually very low leakage, but I have seen some super leaky ones, with signals crosstalking all over the board. I assume those were bad batches. In one case I know it was due to moisture trapped between the FR4 and the solder mask on a large batch of boards. More common its dirty boards, especially in humid climates. Don't fall into the "it isn't a condensing atmosphere" trap. If there is any porosity or dust, that non-condensing atmosphere argument doesn't work. Having dealt with quite a lot of ultra low power stuff I say never discount board leakage until you have checked it out thoroughly.

[Kjelt]

CMOS batteries for clock and settings data retention are normally not used when connected to the mains.
This is because even when the computer is turned off, it is not completely disconnected; it is still supplied with standby power, which is used to maintain the clock and to process when the power button is pressed.

When connected to the mains, the battery is automatically disconnected and operates on standby power. (This is an ambiguous term. It is actually similar, but different.)

I would expect it to hold up fine if left alone for 10 years or so, but if it consumes it after less than a year, is the bad motherboard, is the battery of poor quality, or is it a design problem? I wonder.

This is exactly the issue I cut mains fully off to the PC so there is no 3.3V standby power supply and the battery is 24/7 used. This is not a bad motherboard the quiescent current is large enough to drain a cr2032 if the pc is not used often.

[Kjelt]

Sounds like you may have a hardware fault, but a larger battery might still help. Have you measured the current drain from the cell ?...

Good idea, I will do that this afternoon.

[magic]

Maybe two old fashioned non-rechargeable carbon-zinc AA cells? They are notorious for maintaining fairly constant open circuit voltage even if practically dead, maybe they will be OK for a light load like this for a few years.

[Kleinstein]

The quality of CR2032 cell is scattering. If it was just 1 cell or cells from the same pack, it could be just the battery quality.
CR123 would probably be the next logical step up. Depending on the holder one may get an CR2050 in as well.

[Kjelt]

Just measured 14uA consumption.
With a 200mAh CR2032 that should be almost two years.
Brand coincell was Grundig and they are pretty cheap so could be that the mAh is way less.

[nctnico]

14uA is way too much!

[wraper]

Just measured 14uA consumption.
With a 200mAh CR2032 that should be almost two years.
Brand coincell was Grundig and they are pretty cheap so could be that the mAh is way less.

14uA is a lot. Grundig is a Turkish shit brand for about two decades since it went bankrupt.