A user found a way to charge a 'dead' Pro1X!!! (confirmed by others)

[EskeRahn 5,493]

@Pro1-X jim I split your issue with a not working display into its own thread here. We have other threads on that too, So I might find one and merge them.

[cash 14]

On 7/2/2024 at 6:21 PM, raymo said:

quite easy...too late for me but good to know 😄

I measured 3,20V on the battery connector at red flashing state, is this voltage the very low battery state ? I thought it was more around 3V, but probably depend on battery model/technology

Also I inject 4,1V direct on the battery connector, and in about 30s I had 5% battery, so this trick is very good !

Did you have the red notification light flashing about once per second when trying to charge it?

This seems to be the status of mine too. It's drawing constant 50mA, but even after leaving it for 24 hours, it will not boot.

The rubber band trick is also NOT working for me. I tried several times, leaving it for over 24 hours for one attempt. So I'm guessing you had to disassemble and connect a bench PSU to the battery connector?

[raymo 179]

On 12/2/2024 at 12:39 AM, cash said:

Did you have the red notification light flashing about once per second when trying to charge it?

as far as I recall, yes, the rubber band trick had probably worked in my case but came too late in my knowledge.

On 12/2/2024 at 12:39 AM, cash said:

The rubber band trick is also NOT working for me. I tried several times, leaving it for over 24 hours for one attempt. So I'm guessing you had to disassemble and connect a bench PSU to the battery connector?

Yes

You can also measure battery voltage, but if you fall under 3 volts your battery is probably dead.

Be carefull if you want to disassemble it.

[cash 14]

On 12/5/2024 at 6:39 PM, raymo said:

as far as I recall, yes, the rubber band trick had probably worked in my case but came too late in my knowledge.

Yes

You can also measure battery voltage, but if you fall under 3 volts your battery is probably dead.

Be carefull if you want to disassemble it.

What do you mean by "be careful?"
Just that things are easy to break?

[EskeRahn 5,493]

8 hours ago, cash said:

What do you mean by "be careful?"
Just that things are easy to break?

AFAIK the most likely to be damaged is the cable to the fingerprint reader, at the initial opening of the lower half.

[raymo 179]

There are also some antenna connector on the back (usbC connector side) who connect lower half with upper one, as a ground for antenna if I understand correctly. I recall that @claude0001made a picture in another post, but don't find it anymore.

This is a bit tricky to dismount, but doable. Be cool.

[Hook 3,091]

So, this is strange.  Somehow, even though it was actually connected to power, charging overnight, when I went to check my Pro1x yesterday, it was completely drained of power.  Which is weird... even if the magnetic cable had come loose, I can't see it draining over night.  I was busy yesterday, so I didn't discover it until the end of the day (yes, I actually have days where I don't use my Pro1x, but remember, although it actually seems okay at making calls, I use a Pixel for calls and point and shoot camera and my Pro1x for everything else).  So, this just seems weird, especially as I have a back-up Pro1x that I don't use and haven't installed anything on that I only have to charge every 3 weeks and it still never drops below 70%, lol.

So I have had it on a rubber band now for 24 hours. It still hasn't booted, but I have confirmed it has charged to 21% (it was 3% yesterday) but still isn't drawing enough to maintain that with power hooked up. So I think mine will be one of the 48 hour edge cases. I'll just keep it going until it shows signs of recovery.  I think it will get there, but I'm really curious what could have caused the battery drain.  Is there some other aspect to this bug with the battery that can result in sudden discharge. Probably just I was careless on a couple of really busy days, but still odd.

[Hook 3,091]

I had just posted a "I give up on this" post as endless hours on rubber bands seemed to not be producing results.  But then, just to spite me, lol, it booted.  It was about 22%, I plugged it in and it began losing % again.  So I quickly swapped  in a fast chard 20000mAh Anker external batter and for the first time got the rapid charging message and it is up to 30%.  I think this may be a problem with the Pro1x's charging brick.  Which would explain how it got drained while attached to the charging brick (I tried different cables, so I think it's the brick).

More when it gets fully charged and I make some more tests...

EDIT: Somewhat later. So everything is working again. The Pro1x is fully charged (85%) and it is holding the charge and the brick is able to maintain it, just like my Pro 1.  The rubber band worked but it seemed incapable of getting the phone past about 22% and the brick seemed incapable of providing enough charge when the battery was that low to keep it from losing % but a rapid charge exterior battery worked.   So seems to be an interaction here.  At proper charge levels, the brick is capable of doing maintenance charge, but at some low value is not delivering enough charge to handle maintenance charge.  Not being much of an expert on batteries and charging, I have no idea if these observations make sense.  I still have no idea how the Pro1x got fully discharged, but it must have somehow crossed the line where it was no longer getting enough charge to maintain much less recharge.

If someone who knows what they are talking about has a theory here, I'd love to hear.  I don't even know how to use a multimeter. Lol.

But, for now, my Pro1x is back.  As long as it behaves now, that's all I need to know.  😄

EDIT2: It's the brick. The Pro1x started loosing % plugged in and I noticed when I plugged and unplugged, I would get the lightning bolt for a few seconds and then it would go away. I tested with the brick my Pro 1 uses and that didn't happen.   So I pulled out the brick that came with my other Pro1x and it also worked, retaining the lightning bolt.  I hadn't noticed this detail when the Pro1x was fully charged.  So I have given my old Pro1x the charging brick from the new Pro1x.  Something is just failing in the old charging brick. 

Hopefully, I'm done here.  Lol.

[EskeRahn 5,493]

There still is the bug that has been there quite a while, that the system in that is to protect the Pro1X from being overcharged, sometimes kick in so it will not charge at all.

I see no pattern in when it happens, it can heal it self, so a later charge attempt work. And no it is not a plug issue. Once it charges, no amount of unplugging and replugging will bring it back in the state of refusing to charge, so it is a software bug.

[Hook 3,091]

4 hours ago, EskeRahn said:

And no it is not a plug issue

I agree with you that the bug is a software issue, but in my case, there was an interaction and there was indeed a problem with the charging brick.  If I connect the Pro1x to it's original brick, it now slowly (very slowly) loses percentage and the lightning bolt on the battery goes away.  This does not happen when it is connected to the other brick I have. It's totally reliable to reproduce. 

Talk about a double whammy.  The week was so hectic that I actually didn't pick the phone up for 48 hours and that's how it drained.

[Name_not_avail 65]

I agree that it must be a software bug, and it happens more readily as the battery is aging. Might be connected to LineageOS breaking the original charging software (you recall when offline charging got broken with respect to the stock Android rom, and the LOS devs eventually gave up trying to fix it).

The LED often glows red when I leave the 1X on charging for longer than it takes to hit 100%.

One time I left it charge overnight and it completely discharged the battery, presumably after reaching 100% and then bugging at that point. I had to use the rubber band trick to get going again.

I have set Android charging control to 96% in the settings, and this seems to be an effective work around. Give that a shot, maybe it works for you too.

[Hook 3,091]

23 minutes ago, Name_not_avail said:

I agree that it must be a software bug, and it happens more readily as the battery is aging. Might be connected to LineageOS breaking the original charging software (you recall when offline charging got broken with respect to the stock Android rom, and the LOS devs eventually gave up trying to fix it).

The LED often glows red when I leave the 1X on charging for longer than it takes to hit 100%.

One time I left it charge overnight and it completely discharged the battery, presumably after reaching 100% and then bugging at that point. I had to use the rubber band trick to get going again.

I have set Android charging control to 96% in the settings, and this seems to be an effective work around. Give that a shot, maybe it works for you too.

I have mine set to stop charging at 85%.  🙂

[cash 14]

On 12/2/2024 at 10:39 AM, cash said:

Did you have the red notification light flashing about once per second when trying to charge it?

This seems to be the status of mine too. It's drawing constant 50mA, but even after leaving it for 24 hours, it will not boot.

The rubber band trick is also NOT working for me. I tried several times, leaving it for over 24 hours for one attempt. So I'm guessing you had to disassemble and connect a bench PSU to the battery connector?

An update:

TL;DR: I ended up getting the battery to charge after disassembly.

I left the phone sitting in a drawer until today, as I didn't have time and wasn't looking forward to disassembly. I felt like I was in the mood today and that I had nothing to lose, even if I broke something along the way.

I followed this guide by the way (read all of the tips, as the author is very correct): https://github.com/imax9000/fxtec-pro1-teardown

I managed to not do too much cosmetic damage using a combination of guitar picks, plastic prying tools and small flat-head screw drivers.

Now for the interesting part. Once I finally got to the main board portion, I removed some kind of thermal tape covering that concealed the battery and the connector cover assembly. Then I removed the connector cover, which had several of the connectors stuck to it. I'm lucky I didn't pull too hard and rip off the flexi cables. I was then able to disconnect the battery, get a multimeter on to the terminals and see it showed 0V.

I read many resources on the interwebs saying to not try to revive a 0V lithium ion battery. But they were referring to cells like 18650, which do not have any protection circuitry. I assume this battery has inbuilt protection, so I thought maybe it has gone into low voltage protection.

I tried crocodile clips directly on to the connector, but I don't think they were making a good connection as the connector and its pins are tiny. What I ended up doing was solding two small wires on to the connector. This was not easy and I made a bit of a mess, which I later had to carefully remove without shorting out the battery. But with the jumper wires, I could connect the battery to a bench PSU. I set it to 4.2V and 50mA constant current. Within a couple of minutes, the voltage had climbed and it was above 2V. This is why I suspect that the battery was fine but had gone into protection mode.

I crept up the current over the next hour, checking if the battery was warm or swelling. It was still cold, so stepped up to 500mA. Once it got to about 3.5V, I removed it from charge, checked its voltage with a multimeter, then came back 10 minutes and 20 minutes later, so ensure the voltage was not dropping. It appeared to be stable, so I cleaned up the wires I attached, removed any solder mess, then connected the screen back up.

I connected the USB-C cable and immediately saw the phone was booting!

I am yet to reassemble the phone and will keep an eye on the battery for a while before I do, but from what I can understand, the battery should be fine. Sure, it's 5 years old, so I don't expect a good capacity, but at lease it booted!

[claude0001 1,368]

7 hours ago, cash said:

TL;DR: I ended up getting the battery to charge after disassembly.

Congrats. 👍

I once documented my very similar procedure here:

This was before the rubber-band trick was discovered, so I hadn't tested if that would have worked in my case.

At the time, I also measured 0 V between the pins, but you are probably right, that the internal protection disconnects the cell below some critical value. My Pro1-X has been working fine since (though I do not use it much anymore).

Edited Wednesday at 05:52 PM by claude0001