AppCon power bank for the dynamo of a bicycle

Hello, on my bike I’ve got an excellent SON dynamo which allows me to charge usb devices, not directly as the dynamo produces AC, but via a device called AppCon (which is an AC/DC converter & power bank in one device, produced by the company NC17 in Germany). It works fine with my former smartphones (other brand but also FP3), Garmin, Shimano Di2 battery, etc.).
What a surprise when I notice the nightmare with my FP4! It drained very quickly almost the whole capacity of the power bank while loading the FP4 with 3-4% only, both getting hot before stopping loading. Tried different cables and also at home in a quiet environment (not the same while riding on the bike).
Are there people here with similar experiences? I’d like to read your feedback and most of all the solution(s) you found.
Charging on a usual plug from the net is fine, and also from a « normal » power bank it works fine.
The solution envisaged for me will be to carry another « normal » power bank which can be charged without problem from the AppCon and which can charge my FP4. The main drawback being to use an additional device and its weight (I mainly ride long distances 600km+ in autonomy), as well as the efficiency reduction (two power banks in series, I was told).

Many thanks in advance for your support in the matter,


Did you update your AppCon to the latest firmware? In their blog I see that they had some issues in the past with quick charging devices (don’t know for how long you’ve been using it already). I don’t have many more ideas. From the manual it looks like they are happy to help their users, too, with phone and mail support. I’d try this if no one here comes up with any good idea.

Thanks Martin for your reply. I contacted them directly in parallel to my contact with FP support. They told me (very quickly) that’s a case of incompatibility and I should use another phone for that purpose. It seems hopeless from their side. AppCon is up-to-date also. Mine is from 2019.

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Pew, that’s a pretty poor statement. I doubt that Fairphone can do much about that because it may be related to the charging controller which i assume is fixed logic. So the minimum that the AppCon folks could do is to provide more information about their charging approach. For instance the Forumslader provides 5.3 V to convince most phones that they can take more than 500 mA which works well with FP1/2/3 (haven’t had a 4 to test with yet). Unless they are using any quick charge magic I can’t imagine that it is completely different.

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