Running standalone (with no external sensors) the new Lowrance HDS 8 uses the following amount of power:
|Standby ('off')||0.4 W|
|Booting (display 100% backlight)||14 W|
|Chart display (brightness = 1, backlight off)||5.0 W|
|brightness = 2||5.0 W (usable at night)|
|brightness = 3||5.1 W|
|brightness = 5||5.7 W (usable in cloudy day)|
|brightness = 8||8.9 W|
|brightness = 10||13.3 W (max, very bright even in sun)|
Enabling the sonar added 2 to 3 Watt. In fact the sensor usage is the only difference between Standby and running with the backlight very low or off.
This was all measured at the wall plug using a laptop AC to 12 V DC converter and a Voltcraft Energy Check 3000. Actual power use measured at the DC input should be about 15% lower still.
All in all I am extremely satisfied with this new plotter -- Excellent functionality, great NMEA 2000 interfacing, great screen, cheap charts, all for a very reasonable price. I got mine from JG Tech in the UK.