29 May 2009

Apple 30" Cinema HD Display power usage

Now that I've got the power meter out, I've started measuring more stuff than what's going onto the boat. Maybe having actual figures will help somebody out there.

For instance, my Apple 30" display at the office uses up to 150W according to Apple. The actual consumption figures that I've measured are:

SettingQualityPower
0%On the dim side, but still pretty good51 W
50 %Normal office use75 W
100 %Good for use with indirect sunshine114 W

11 May 2009

Simrad/Lowrance NMEA2000 network power usage

Third in what is turning out to be a small series on power usage. This time I figured I'd benchmark the power usage of all the navigation equipment that I have collected so far for the new boat.

Again measured using a Voltcraft 3000 at the 230V AC, so the actual figures are too high by 10-20% when using a direct 12V DC source. Since I am going to use a 24 V to 12 V DC/DC converter that will probably have the same sort of efficiency as the AC/DC converter that I am using now, I figure these measurements are good enough for me personally.

DevicePowerCumulative
Lowrance HDS-8 (backlight @ 6)6.3W6.3W
Simrad IS20 Wind wand0.9W7.2W
Airmar DST800 depth/speed/temp sensor1.0W8.3W
Lowrance EP-65R fluid level sensor0.4W8.7W
Navico NAIS-300 AIS-B (receive mode)7.3W16.0W
Simrad RC42 compass0.9W16.9W
Simrad IS20 Graphic display0.8W17.7W
Simrad IS20 Multi display0.6W18.3W
Simrad IS20 Wind display1.0W19.3W
Simrad AC42 course computer2.5W21.8W
Simrad AP24 auto pilot controller0.8W22.6W
Airmar P319 sonar (depth) sensor1.4W24.0W

As always there are some small surprises here:
  1. The chartplotter only uses 25% of the power envelope
  2. NMEA2000 nodes seem to use at least 0.4W.
  3. The NAIS-300 uses more power than I'd thought it would. Being able to shut it down completely is something to be considered.
Note to self (and reader): this is on the benchtop, the following is still missing:
  • RF300 rudder feedback (should be neglible)
  • Hydraulic pump (e.g. using the autopilot as opposed to just having it in standby)
  • VHF #1
  • Simrad WR20 remote
  • Broadband RADAR sensor
  • Ethernet switch

05 May 2009

Lowrance HDS 8 power usage

Finally had a chance to hook up parts of the new NMEA 2000 kit to the power meter.

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
Standby5.0 W
Chart display (brightness = 1, backlight off)5.0 W
brightness = 25.0 W (usable at night)
brightness = 3 5.1 W
brightness = 55.7 W (usable in cloudy day)
brightness = 88.9 W
brightness = 1013.3 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.

Apple 24" LED Cinema Display power usage

Yesterday I was trundling the isles of Office Center, and noticed that power usage is now getting more attention of office/home TFT display manufacturers. Good!

In particular they had a LG 22" display that only used 22 Watt at full backlight. It was not very bright, but it was fine for office or home use.

As they had a power meter attached, the power claim of 50% reduction was easily verified. At full backlight usage hovered around the 21 W mark. It also showed that it only used 11 Watt at the lowest backlight setting, where it was still somewhat visible.

They had one of the new 24" Apple LED Cinema Displays. An employee asked whether I had any questions, so I asked whether it was OK to move the power meter to the Apple displays to check out how much power they were using. Lo and behold the manager turned up, said yes sure. We set the meter up with the Apple display. The results were:

SettingQualityPower
0%backlight off or almost off; not watchable11 W
20 %Normal office use20 W
40 %About as bright as the LG at 100%30 W
100 %Very bright88 W

I was amazed by the range actually. Certainly in that store the picture was usable at 20-30 W, meaning you can easily save quite a lot of energy by turning your screen down a bit.