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    Power consumption of LEGO Bluetooth elements

    Here below I have a look at battery power consumption of the following devices : Boost, Wedo 2 and Powered Up hubs, and Powered Up remote handset. During regular usage, most of the power consumption is caused by the active elements (motors), but the idle power can be significant too, especially for programmable devices that are often "on" while you are writing/debugging programs!

    Some caveats...
    - The measurements were done on only one device, I may have got an exceptionally good - or bad - device!
    - I used a simple multimeter, this kind of tool is not very good at measuring pulsed currents. I don't expect this to be a major problem as a capacitor filters power supply on the electronics boards.

    The battery life quoted below is the time an average alkaline battery would last at the considered current. I used a capacity of 1000mAh for the AAA cells and 2500 mAh for AA cells (WeDo 2)

     

    WeDo 2

Device State

Consumption

Battery Life

Off

2.5µA

> self discharge time

Waiting for pairing

15mA

7 days

Paired

15mA

7 days

With tilt sensor

26mA

4 days

With distance sensor

37mA

3 days

With motor (stopped)

65mA

1.5 day

With motor + dist. sensor

92mA

27 hours

     Overall, thanks to the large capacity of the AA cells of WeDo 2, idle consumption is not a significant issue.

     

    Boost Move Hub

Device State

Consumption

Battery Life

Off

~ 0

> self discharge time

Waiting for pairing

47mA

21 hours

Paired

49mA

20 hours

With color sensor

54mA

18  hours

With color sensor and external motor connected

71mA

14 hours

With color sensor and external motor,
program running, all motors stopped

145mA

7 hours

    For the Boost hub, the idle current consumption is significant. Worse: if the program stops without an explicit end of program, the current remains at 145mA instead of going down to 71mA.

     

    Powered Up Remote Handset

Device State

Consumption

Battery Life

Off

34µA

3 years

With a button pressed

120µA

1 year

Waiting for pairing

4mA with 7mA pulses

8 days

Paired

6mA

7 days

Paired, hub far away

3.7mA

11 days

Continuously transmitting

6mA

7 days

    The power consumption in Off state is a bit high, but nothing really worrying. As a general advice, don't let batteries in any device as they might leak... For a reason I can't explain, the power consumed is lower if the hub is far away (3 - 4 meters). The paired current depends slightly on the LED color (channel), 5.2mA for green to 6.7mA for blue. Probably the LED current was adjusted to keep the same brightness...

     

    Powered Up Hub

Device State

Consumption

Battery Life

Off

~ 0

> self discharge time

Waiting for pairing

41mA

24 hours

Paired

41mA

24 hours

With both motors braked
(both remote handset red buttons pressed)

88mA

11 hours

     

    Idle power consumption of Powered Up hub is OK, even if AAA cells make it last less than WeDo 2 with its AA cells!

     

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