Power consumption of LEGO Bluetooth elements

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!