Charge problems since I bought a Samsung external Battery

Hi, I’m having charging issues with my Fairphone 3+.
When I plug it in, it seems to charge slower than before, and while the cable is still plugged in, it suddenly stops detecting that the cable is plugged in and then continually redetects it.
I recently bought a Samsung 20,000 mAh power bank (QuickCharge 25W) and I’m wondering if it has damaged my FP3+.
Here is the battery model I bought: 20,000 mAh Battery Pack PD, Dark Gray Mobile Accessories - EB-P5300XJEGUS | Samsung US
Do you think it’s related, or do you think it’s just a coincidence?
Can someone confirm this battery is compatible with the Fairphone 3+ ?
And what do you think I should do?

Welcome to the Fairphone community.

Did you check the USB connector for damage or debris? Can you try different cables and chargers?


To me that’s typical with a damaged cable or problem with the port.

It’s not the battery that has to be compatible as that isn’t connected to the phone, it’s the charging chip in the power bank that communicates with the power chip on the main board than communicates with the phone battery.

Quick Charge 2.0, and Power Delivery 3.0 standards for fast and safe charging.

The FP3 uses QC3 not QC2 so it could well be a communication problem.

Although as above it could be a physical connection issue, so clean the USB port and check the cable with a few other devices and try a ‘new’ cable.

Difference between QC 1.0 and QC 2.0

  • Speed difference:
  • Voltage variation:
  • QC 1.0 supports up to 2A and operates on 5V.
  • QC 2.0 works on a multi-voltage charging system offering 5V, 9V and 12V up to 3A. This multistage voltage means when your device battery is really low it charges with 12V, this allows for a really rapid charge, then as the charge gets highest it slowly kicks back the V until you reach normal QC 1.0 voltages and speeds.

Difference between QC 2.0 and QC 3.0

QC 3.0 builds on QC 2.0’s voltage variation, but instead of only 3 voltages, it can vary to any voltage between 3V and 20V. It is around 15% faster than QC2.

Yes I checked that before posting here.

No the problem comes from the phone.

In 2 years of intensive usage, I had never had any problems with this phone using 1A or 2A chargers or batteries. I would even say that it worked perfectly.

I started having problems when I bought the samsung quick charge battery (mentioned above).
I now have a few weeks of hindsight and here is what I did and tested.

I tested several chargers, as well as several cables.
Some cables work better than others, but I think it’s a matter of connector design.
So I extracted the bottom module, I cleaned the internal usb connector, and I tightened it with pliers (be careful if you do that, it’s very fragile). The result is that all the cables are working and the detection of the charger is good.

Then I hadn’t noticed before, but when I plug the phone in, it often goes into slow charging mode (and rarely in normal charging mode).
And when I plug on the quick charge battery, it often goes to slow or normal charging mode (and rarely in fast charging mode).

Sometimes I put the phone to charge, and the yellow light on top turns on, but the phone does not charge.
And sometimes I put the phone to charge, the charging mode starts, and when I come back to check a few minutes later, the phone no longer charges even though I haven’t touched it and the cable is still plugged in (no charge information on unlock screen, and no lightning logo on the battery icon).
Unplugging and reconnecting the cable causes the charge to restart in these cases.

Searching the forum I find a lot of people having slow charging problems, and I think it’s related. Using this quick charge battery triggered this problem in my phone in slow/normal/quick switch charge.

I do not know if it is an hardware of software issue. Do the slow/normal/fast charging mode a software or a hardware switch? Where is it placed? On which module?

My phone is no longer under warranty and I wanted to change the bottom module to see but they are out of stock everywhere.

Do you have any suggestions to help me fixing my issue?

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In a case like this a fairphoneangel may be able to help by lending a bottom module or testing yours in another phone. Check the map to see if there’s one near you. Or you might be able to get in touch with another FP3 owner who could help.


Hello thank you, where is this map? :slight_smile:


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Okay thank you but there is nobody in my town (Lille).
Do you know if bottom modules will be available soon?

No, we as users like you don‘t know.

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Hello, to let you know I managed to get a brand new bottom module and now everything works well (Fast charge etc…). So yes it was a problem with the old bottom module, thank you for your help!