ok thank you, but what about with the unpluged battery?
The Plan is, a little Switch between the psu and the Battery.
when the switch is "off", I only play on the external psu.
and "on" I charge the battery.
so that Helders psu doesnt have to load and play at the same time.

Hi. Can someone tell me if I can use the psu without a battery.
as it were a normal powerboost.
If so, what is the optimal input voltage so the psu gives the 3.5A

well .... with play and load should not be a permanent solution but it should be possible.
Okay. Thanks for the Info's

Hi Helder,
Thanks for your psu. I still have an external power supply with 5.45 v and 4a, can I use it or should I buy another? Or what would be the maximum input voltage? Sorry for my stupid questions in bad English.
Greez