I believe it really wants 7.5V, but will operate on 6-8. Not 12, though.
da-p1 will run safely at 13.5v. i run mine on 12v. even the output of the da-p1's ac adaptor is 13.5v, although it states 7.2v on the box.
marc
??
I have measured the UNLOADED voltage out from the DA-P1 AC adaptor to be 13.8 Volts DC. But it drops to a stable & well regulated 7.5 Volts (measured at the DA-P1 input terminal) when delivering the 650 to 800 or so mA the DA-P1 uses.
There are two power supply capacitors within the DA-P1 that see the DC input voltage. They are both rated for 10 Volts operation.
I take your statement above to mean that the DC-DC converter tackles a fully charged lead acid (13.6-14.5 Volts I imagine depending on your charger?).
Heat should not be a problem for the DC-DC converter. But linear regulators develop heat in proportion to the voltage across and heat shortens the expected lifetime of semiconductors.
I.e., I would not exceed 10 Volts when powering the DA-P1 with an external DC source.
Jon