Charge FP4 with a 6V solar charger. And a 20V?

What are voltage and current limitations for FP4 battery charge, please?

I would like to commercialize small PV panels with USB output of 6V 2A max, but is it safe to do it on a daily basis?

Moreover, I have a USB-C computer charger of 20V and I have tried it once to charge very quickly my FP4.
And it has worked.
What are implications please?

Finally, I know our smartphone batteries should remain between 10% and 90% charge levels (DoD).
Any app’ or feature to recommend, to keep it this way please? I have set up the Fairphone warning for low charge, but I would like to stop charge at night at 90%.

Thanks for your reading and support,

Please see this discussion, I think there are more in the Forum when you search for it

The App AccuBattery can warn you with a tone when a limit is reached. To stop charging you need root or another custom ROM like Iode

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Hi You say panels, implying more than 1.

With 2 to 4 in series you get 12 to 24 V and you can use a 12|24V cra charger with QC3 output to do a fast charge.

You would be better finding an ols 12V battery to connect the panels to and then the charger to that.

A computer charger of 20V ? USB C outputs do not give 20V by default, they provide 5V and then negotiate with the device and can supply up to 20V often in steps (9,12,15,20)

I have a Raspberry Pi USB charger with a USB C plug. However it has a voltage of 5.1V not 5V - Will this cause a problem for a FP4?

Hi and welcome, I moved your post, please see above linked topic as well.

Hi and welcome to the forum.

You should be fine. I have a 3A 5.1V mains supply for a Raspberry Pi too. It may charge a bit slow but it’s fine. I use it on my FP3

All the best

Thanks, good to know…

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