Viability of an ML 1220 rechargable battery for RTC | CMOS (11th gen)

Community Support
441

Sadly that should be fine, and 24hrs more so.
It would be useful to know what charge rate there is for the ML1220 as we ‘know’ the capacity is around 17/18mA/h

The nominal discharge is 0.03mA/h (Panasonic data) 0.1mA/h (Maxell data)
Days to discharge @ 0.03mA/h = 21 days @ 0.1mAh = 7 days

Given a charge rate of 1mA/h the battery would charge in 17 to 18 hours.
However when the battery is below 10% and above 90% the charge rate is likely to be dramatically reduced, hence the 24 hour advice to charge.

However depending upon it’s 'life; cycle that could be dramatically reduced.

As the charge rate depends upon the voltage even a small resistance cause by tarnishing, low contact pressure, poor soldering etc. will mean the battery never reaches it maximum voltage, yet the charge will stop prematurely.

This is why Framework ‘more or less insist’ that a) It is charged for 24 hours and b) the battery should not be replaced as it may be a fault external to the battery.

Quote
442

Yeah the fact that the battery cradle keeps popping up seems to me it’s a reasonable size batch.

If my issues are purely the CPU bug then I can work around that but if it’s a bad cradle then I want that sorted before I pass it on.

1 Like
443

EDITED: Ahh, you meant popping up as in being mentioned, not “popping up” off the board. Yes, let’s figure out what the root cause is.

1 Like
444

I shall report back. :thinking:

1 Like
445

Yeah, this is what happened to mine too. Mainboard resets became a routine part of my boot process if I let it power down for longer than a minute (even after letting it sit on the charger all week). Laptop used to work fine for 10 months until I left it unpowered/unused in my backpack for a month, which I assume killed the RTC battery.

My workaround was to avoid turning off the laptop and always travel with the screwdriver and a SIM eject tool handy for booting.

446

If you’ve performed the mainboard reset, let it charge for 24 hours, and are not consistently leaving it unused/not on a charger for weeks/months, and are seeing the reset consistently, please contact Support. Either the battery can no longer hold voltage or there’s something wrong with the RTC cradle. The Support agents have updated instructions to assist, even outside of the warranty period.

3 Likes
447

Yes that can easily happen. It was a design oversight not to have battery, in the 11Gen being charged from the main battery. This maybe why support are happy to help in this situation even though the warranty has expired. Hope they keep that up for the 11Gen for - a long time.

448

OK More info on the ML1220

This is taken from https://www.abcde.de/data/ml1220_datasheet.pdf

ml1220charge
ml1220charge760×509 27.4 KB

In case of the datasheet URL becoming unavailable I also have a copy

Note the recommended usage is from 80% to 100% (maybe 77% to 78%) and clearly taking the battery below 20% is a no go.

With nominal drain of 0.03mA/h and 20% of capacity being around 3.5mA/h the 11th Gen should not be off mains power for longer than 166 hours or again 6 to 7 days.

This is a generous ‘advice’ as the battery will be loosing capacity from day 1 and if not treated extremely well will be degrading rapidly.

So a design that really only permits the laptop to disconnected from the mains for a week, without damaging the ML1220 is quite an oversight, and arguably not fit for the purpose that many customers may unwittingly put the laptop too. i.e. leaving it not plugged in for 6 days
:scream:

6 Likes
449

Interesting, but unplugged for 6 days max just sounds too short. I mean, when brand new, how many days did these laptops spend in inventory and shipping to customers? Why did that time unplugged not kill the RTC?

I enjoyed 10 months of hassle-free use after my laptop’s delivery, and it sure felt like I waited a long time for it to arrive at my door.

2 Likes
450

Yes that’s a relevant point.

The 6 days is the time it takes to deplete the Ml12200 by some 20% so it can travel for two or three of weeks and still switch on.

A perfect battery can last 3 weeks. Some people have a problem and maybe that is due to a slow delivery from assembly to delivery.

There’s also the issue that the laptop is delivered in a state where it will not turn on without first connecting it to a power supply. This may have the effect that before that so much of the hardware is disconnected electronically that the ML1220 has a far reduced load. That would be nice to know too :slight_smile:

2 Likes
451

UPDATE: Nirav’s update on this is here with links to the datasheets: Viability of an ML 1220 rechargable battery for RTC | CMOS (11th gen) - #453

Just to provide an update, this is being tracked down in coordination with our team in Taiwan as we want to make sure we’re providing the most accurate information. I’ll update here once I have the appropriate information to share. Thanks for your continued patience.

4 Likes
452

Today my ML1220 died (it seams to leak “dust” and settings are not saved, when switched off and it starts twice until it boots). I have not found it anywhere, can anybody tell me where to buy a replacement in germany?

Is this issue fixed with Gen 12 mainboards?

1 Like
453

Hi all, as @TheTwistgibber noted, we have been reading through this thread carefully and listening to everyone’s feedback. There are a couple of actions we’re going to take to improve the experience for 11th Gen users who are finding that they need to reset their mainboard every few weeks or more often. Note that for the vast majority of 11th Gen users, who are using their laptops more often than every few weeks or months or who keep their laptop plugged into power when not in use, there should be no impact or need to engage on these actions.

RTC Battery Replacements

First, if you’re finding that you’ve needed to perform the Mainboard reset procedure more than a few times on your 11th Gen system after long periods of non-use, we will provide you with a free replacement RTC battery, even if you are outside of your warranty period. We will continue to do this for as long as we are able to get supply of these cells.

We’ve uploaded the datasheets for the two cells that our manufacturing partner had been sourcing for us during 11th Gen production. The key callout is that while cycle life is reasonable during normal shallow discharges, doing a full 100% discharge of the coin cell more than 10-12 times results in serious capacity degradation. From what we have seen, this is typical of Manganese Lithium coin cells, but we are reaching out to other coin cell makers to see if anyone has parts that handle deep discharge better.

Note that because these are bare Lithium Ion cells, they require very careful shipping to comply with transportation safety regulations. We’re working with our shipping carriers in each region to set up compliant shipping paths, so it may take some time for us to turn on shipments of these coin cells for all supported shipping regions. We have a small quantity of cells in the US currently, and we’re working on sourcing more of these from our suppliers, which similarly will take time due to lead times and handling requirements. Note also that we are only able to ship these cells to our supported shipping regions. We will also be listing the coin cell on the Marketplace for folks who are interested in purchasing them outside of this replacement process.

After you receive your replacement RTC cell, please make sure to let it fully recharge by keeping your laptop plugged into power for at least 72 hours. We also recommend keeping your laptop plugged into power during long periods of non-use to avoid letting the RTC battery fully discharge. Note that even a normal 5V/900mA USB-C power adapter will sufficiently trickle charge the system and RTC cell. Finally, we also recommend keeping your system up to date with the latest firmware releases. We’ve recently released 3.17 BIOS for 11th Gen.

Rework instructions for 11th Gen Mainboards (For advanced electronics repairers only)

While the above is available to all 11th Gen customers, we have an additional item that we do not recommend except for those who have both advanced soldering equipment and advanced electronics rework experience. This is a circuit modification for 11th Gen Mainboards to charge the RTC battery circuit at all times as long as the main battery is connected, even when the system is off. With this modification, the RTC battery can actually optionally be removed. This modification will make the 11th Gen similar to 12th Gen Mainboards where the RTC circuit is powered and charged directly off of the main battery. Note that because this is an advanced and difficult rework, this is not something we will be providing additional support around or warranty replacement in the event that you damage your board in the process of performing the rework. We will only be providing the instructions for doing the rework. We are currently writing this as a Knowledge Base article and will post in this thread once it is up.

20 Likes
454

Very interested to know what the rework will be. Great that FW is making this an option but I’m feeling like we will see mainboards with ripped pads.

3 Likes
455

Thank you.

I had written a letter some 8 months ago but kept with this thread thinking I will modify my letter. Luckily some of my queries have been answered :slight_smile:

First let me thank you for the

we will provide you with a free replacement RTC battery, even if you are outside of your warranty period. We will continue to do this for as long as we are able to get supply of these cells.
That is the honourable thing to do :+1:

On the modification.

I was planning to do something when the warranty expired.

I was going to add a small dc to dc converter between the main battery to supply 3v to the ML1220. Now it looks like I won’t have to. Back in the 60’s I was a radio electrician and hopefully my fingers are still nimble enough.

This is all very good news :tada:

Thank you again

:om:

All the best

It may be a good idea to put it a the top as a sticky and put a link to the above post.

Looking forward to seeing what you have in mind :slight_smile:

1 Like
457

This is exactly what I hoped to hear, thank you!

1 Like
458

Okay 24 hours on charge. Unplugged the power and it fired right up.

I’ll leave it 48 hours and see it if powers up again.

1 Like
459

While I’m waiting for the replacement mainboard for the replacement mainboard (hasn’t shipped yet, confirmed on the 4th but… crickets, still just “confirmed”, not sent. Initially figured it might be chinese holidays, but I’ve seen reports of people ordering laptops after that and already having them), I have a question: does this mean it might be a good idea to remove the coin cell in case a longer time away from wall power is expected? (Eg. if replacing the 11th gen with a 12th, but intending to use the 11th gen board for something else “whenever you get time”. In my case, it would probably become a Proxmox box to replace my raspberry pi stack, but no time for that now.)

Throughout my support experience, it’s been a bit weird to be told to be extremely careful with replacing the cell because the cradle is fragile - but let’s have you take it out for the 5th time as part of troubleshooting. :stuck_out_tongue:

If that is the case, this might be good to document somewhere. Since the 10-12 times can be reached fairly fast for a board you use in learning projects.

3 Likes
460

Figured I’d check in since recent developments in this topic: As promised, support was understanding and ready to send a replacement ML1220. The FDK battery from Amazon continues to work well, but I feel putting the manufacturer sourced cell in is the best option in the long run. Once it’s arrived, installed, and charged, I’ll check back in.

I promise I won’t blow up your forum notifications anymore, but thanks again to @nrp and @TheTwistgibber for your attention here. Sincerely appreciated.

3 Likes
461

I might, though… :stuck_out_tongue:

@TheTwistgibber a question. I just got my ticket escalated to logistics, since the replacement for the replacement isn’t shipping, it’s just stuck in “confirmed”. Given that support previously was under guidance that cell replacement is not a thing and mainboard replacements are what does it. (And appear restricted in their ability to give anything but the copy-paste answers to questions.)

Then the replacement mainboard was a desktop. Then the replacement for the replacement doesn’t end up shipping at all… Guidance seems to now have changed after my case started back in November, so is this a situation where the “correct” option for my original issue is actually to just get my original board one of the replacement cells and let’s be done with it? (I’d otherwise have been tempted to request an annulment of the whole purchase.)

At this point I am really at a loss of words because this crap is taking so darn long to reach any kind of conclusion, but luckily for Framework I’ve grown fond of the 3:2 screen ratio (great with a vertical split in vim while coding) and there’s a dearth of options in that form factor that aren’t soldered down.

Given the information shared recently, it really seems like my case could have been solved all the way back then. But not knowing whether this recent change affects the whole “we looked at your pictures of the RTC cradle and will replace the mainboard” I’ve gotten twice…