Battery does not charge - Maybe caused by Read NFC

Troubleshooting
#1

As seen rarely before in this forum, today my Flipper Zero stopped to charge properly. The second time.
For example this post with solution: Battery stuck at 49%

My symptoms:

  • It charged with up to only 76mAh
  • It says at 30% ‘all good’
  • The LED blinked shortly green and back to red

So I needed to open the Flipper Zero the second time, disconnected the battery, waited 10 minutes and plugged it back. The Flipper Zero started and says ‘87% Battery’. Everything is fine again.

But why I started a new topic:
I observed it happens both times while/after reading a Mifare NFC card, while testing the keys.
At the first time I’ve read a old employee card, I’ve had at home. Today I’ve read a access card from a camping site.

I am curious if others with this behavior have also read a NFC card, before.
@Calidora_52 @sawyer @Mystic0x31

@Astra Are the Devboards still available? It would be more easy to debug this, if I don’t need to disassemble the Flipper each time :wink:
If not, maybe somebody with a devboard could help out.

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#2

You know what. It was after reading an NFC card that it started for me as well. Interesting, I have a second flipper. It’s doing fine so far. Do I dare experiment.

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#3

The last time I managed it , i was just reading in sub-ghz, without hopping, just out of nowhere, I also did not see any logical reason to cause this ,and trying it on purpose after reflashing it etc does not seem to be that easy, so i do wonder how it happens, but just disconnecting the battery and have a break seems to be the best solution. Sometimes replugging USB while holding middle/back button also got me back into DFU but there seems to be a state where it goes into panic, and physical disconnect of the battery works?

It could be a total coincidence but the times i managed to get those states the batt temp was over 36C on hot days being idle, so maybe it panic if it goes over average?

#4

If this starts happening to me I may consider adding a little reset pin to the battery. It would be very annoying to take apart repeatedly. The only freezes I have had so far have been fixed with the two button reset or 30 seconds on the back button.

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#5

I actually was thinking about adding a small switch so i do not have to remove the plug, but so far i only managed to do this twice where i actually had to reconnect it. But adding microswitch to it might be a good idea if you are reflashing it far to often :slight_smile: my target is to keep it original as long as the battery lasts, as soon as that needs replacement anyways, i might add a little switch. till then im keeping it in its original state.

But it does hit your feelz when you cannot get it to boot or DFU anymore or it starts to act weird, but it is kinda soothing if you just had to remove a couple of phillips screws and just disconnect it. The plastic however with the screws do need some feeling of tension , so you do not break it and you also do not make your flipper sound like a squeaky toy.

So if it happens more often i think the switch is a good upgrade.

1 Like
#6

The devboards are still available, yes, but having one won’t really help with debugging this particular issue. You can run power info and power debug in the USB CLI to get all the needed data.

However, the NFC Read is most likely just a coincidence, it has no ability to affect the battery. The issue (to the best of our knowledge) is caused by the battery connector not mating properly with the socket, which in turn makes the connection between the contacts worse.

This doesn’t really affect the positive and negative wires, but the middle wire, which is for the temperature probe, uses the resistance to calculate the internal state of the battery (and protect from overheating). A bad connection makes the resistance higher, which confuses the power management IC and breaks all the calculations that it does, which results in unexpected charging behaviour.

This physical problem isn’t affected by anything that NFC could do (apart from hitting your device with a card really hard, maybe).

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#7

I’ve had the DevKit (Flipper on plastic frame) in mind for easy battery disconnect/connect, not the DevBoard (GPIO thingy) Sorry.

Thanks for the heads up, I’ll try the next read with the power commands.

#8

Ah, the devkits have been discontinued more than a year ago, unfortunately. They were all made pretty much by hand, so we switched away from them as soon as we could, it was too expensive to produce them.

If you have a Flipper that you can mod (possibly irreversibly), you can remove the orange SD card holder/strap reinforcement piece and route the cables through the strap holes in the case. That would require splitting the battery wires to make them longer and to install a switch, though. Not sure how relevant this is for you, but that’s our usual method for routing wires out of the Flipper.

But just running power info and debug should be more than enough, and definitely not as destructive :stuck_out_tongue:

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#9

I believe 30 seconds on back button is a reset on battery. It goes to a separate pin on charge controller.

#10

Thank you for the excellent explanation! I see how that could be an issue.

#11

It seems as though this does not work for some people in certain circumstances. Unless I have the issue and the usual reset options don’t work I don’t plan to do it.

#12

Yeah the 30s is not enough apparently if you mess up the temp sensor, but if you do it after reconnecting the battery for me it instantly got DFU working again. But except some hot days, I saw little other reasons for it to go panic, I did not drop it before or anything like that, so not sure why but if temp-panic is triggered it does seem to prefer a physical reconnect. Lucky I only had to do this twice afer breaking the firmware/configs and apps multiple times over.

1 Like
#13

I had the same problem and re-plugging my SD card helped.