12 VDC Power for Preamplifier

[theoleman]

I've got off grid property that I'm putting up a tower. My plans are to include a preamplifier that requires 12VDC 0.5A. The preamplifier is normally powered by a wall wart. Rather than placing a DC-AC inverter into the existing 12VDC setup for said wall wart; could I power the preamplifier with 12VDC from the battery and a resistor to reduce the amperage to 0.5A?

I've searched on this subject for sometime but haven't found anything explicit on the subject. RVers usually have an onboard inverters. Seems that off gridders only want power for their cells and computer. One company has a 12VDC to 12VDC 0.5A trickle charger. I hesitate to go this direction because of the expense. I also hesitate on an inverter because of the expense, noise and finding a larger box to mount it in.

I appreciate everyone's suggestion and comments.

ToM

 

[prcguy]

I've got off grid property that I'm putting up a tower. My plans are to include a preamplifier that requires 12VDC 0.5A. The preamplifier is normally powered by a wall wart. Rather than placing a DC-AC inverter into the existing 12VDC setup for said wall wart; could I power the preamplifier with 12VDC from the battery and a resistor to reduce the amperage to 0.5A?

I've searched on this subject for sometime but haven't found anything explicit on the subject. RVers usually have an onboard inverters. Seems that off gridders only want power for their cells and computer. One company has a 12VDC to 12VDC 0.5A trickle charger. I hesitate to go this direction because of the expense. I also hesitate on an inverter because of the expense, noise and finding a larger box to mount it in.

I appreciate everyone's suggestion and comments.

ToM

If the preamplifier draws 500ma @ 12V then that's what it uses when supplied 12V. Just connect to a 12V battery and it will work as intended. However, 500ma over a 24hr period will use about 12 amp hours of battery power so you need to design the battery/solar system accordingly.

 

[davidgcet]

put a 0.75 or 1A fuse in line to protect it. no need for a resistor