I am working on refurbishing an old ghettoblaster using a Raspberry Pi 3 + HifiBerry AMP2. (I will post pictures and schematics once it is done :) ) I will start by using the stock loudspeakers (7 ohm, 2*2W), but in the long term I will replace them by car loudspeakers (4 ohm, at least 2*30W).
I am wondering whether it is recommended to power the AMP2 from a battery? Given that the battery voltage is not very stable. I am still hesitating between these two batteries:
- LiPo 4S, 14.4V. The output current will be more than enough, but the voltage will drop as the battery empties.
- Regulated 12V Li-Ion battery. The voltage is regulated at 12V, but the max output current is only 2A, which might not be enough for the AMP2 at full volume.
Which leads to my next question: what is the maximum current drawn by the AMP2 + Raspberry Pi 3 under the conditions I mentioned?