Power draw Android tablet Vs. Windows Tablet

[GreenHeaven]

It is becomming increasingly clear that I am going to have run OpenCPN and something else to display an engine dashboard in Windows. A laptop is much too power hungry for days of navigation, so thats why I chose a tablet.

My understanding is that an Android tablet is significantly less power draw than a windows laptop (and more readly available and cheaper)

Has anyone compared the two? got real world experience with a windows tablet for cruising?

[JohnGC]

The single largest current draw of any plotter is the screen backlight. I include Raymarine, Garmin etc in that statement as well as a Raspberry Pi, laptop and tablets of any type.

Managing the screen backlight by allowing screens to be turned off will have a significant impact. Also the type of backlight is important. Modern LED backlights use less power than older cold cathode types. Bigger screens need larger backlights = more current draw.

When measuring the current of a device with a battery, you must let the battery finish charging before taking a reading. Battery charging takes at lot of current but only for a relatively short time.

Here are some real wold readings for a 10" Windows X10GX tablet on a 12V boat system. It was powered by a 12V to 19V DC to DC convertor.

With fully charge batteries;
===========================
Measurements at 19V into tablet.
Full brightness screen: 1.04A
Min brightness screen: 0.81A
Screen off: 0.79A

Calculation for 12V (IE input into the DC-DC convertor)
Full brightness screen: 1.65A
Min brightness screen: 1.28A
Screen off: 1.25A


With flat batteries (IE charging);
===============================
Measurements at 19V into tablet.
Full brightness screen: 2.88A

Calculation for 12V (IE input into the DC-DC convertor)
Full brightness screen: 4.56A

..................

These figures are not significantly different from a previous 10" Netbook I used. I now have a ASUS BeeBox plus rugged 12" screen which is bright enough for outdoor use. The screen backlight uses more current at full brightness. But otherwise the system is much the same.

Whilst it is true that a RaspberryPi can use less current than a Laptop. It still needs a display of some sort and that display is likely to require more current for its backlight than any of the other system parts.

[Tupaia]

I agree with JohnCC



I run an ASRock Beebox but specifically chose it with an N3000 (later N3050) dual, not quad processor. This has a very low SDP and TDP rating and with the screen physically switched off has a minimum power consumption. It has a relatively small SSD and it also runs directly off the house bank so no voltage conversion (heat) loses. For the purposes of running OpenCPN and Dashboard the requirement is to run constantly in background you do not need huge "processing" power so a lesser performance less power hungry chip will work fine. Don't forget to disable wifi, bluetooth and avoid hardwired lighted keyboards and mice.


I have also run a RPi but found the Beebox to be more reliable. But the key is to have a switchable screen.

[JohnGC]

Tupaia you are correct.
Beebox = ASRock not ASUS as I stated.

FYI: I have run my BeeBox on a bench PSU at 6V and at 16V and it seems to be good.
I asked ASRock for the PSU spec but it wasn't forthcoming.