Battery solution for Nano Every Project

Official Hardware Nano Family Nano Every
1

Hello I'm planing a battery powerd device that will measure temperature, humidity and air pressure over a period of about 60 days. I thought of a BME 280 sensor. The measurement period would be every 5 or 10 minutes (measurements: 8600 - 17000). In the meantime, the device should run in sleep mode. For this I would need the power consumption of the controller. The power consumption of the BME 280 is a maximum of 0.3 microamps in sleep mode and 1.3 mA during measurement. Which battery can you recommended?

Wenn einfacher gerne auch auf deutsch.
Ich plane ein Batterie betriebenes Gerät, dass Temperatur, Luftfeuchtigkeit und Luftdruck über einen Zeitraum von ca. 60 Tagen messen soll. Dabei habe ich an einen BME 280 Sensor gedacht . Der Messzeitraum wäre alle 5 oder 10 Minuten (Messungen: 8600 - 17000). In der Zwischenzeit soll das Gerät im Schlafmodus laufen. Dazu bräuchte ich den Stromverbrauch des Controllers. Der Stromverbrauch des BME 280 liegt im Schlafmodus bei max. 0.3 Mikroampere und während der Messung bei 1.3 mA. Welchen Akku könnten Sie empfehlen?

2

You can ignore the BME280 as the sleep current is so low.

The key bit of information is what is the sleep current of the board.

Does anyone know what the sleep current of the Nano Every is ?

3

@srnet, the 4809 can go down to 15 uA according to the datasheet. But there is also the ATSAM11D and I have no idea if one can get that in some low power mode.

Battery power is expressed in Ah. A battery that is specified for 1Ah can deliver 1A for 1 hour or 2A for 30 minutes or 100 mA for 10 hours; and so on. And the minimum voltage for 16 MHz is 4.5V.

4

I note that the regulator used by the Nano every, AP2112K, has a quiescent current of 55uA, so its unlikley the designers had low sleep current in mind for this board.

5

I found a page that compares the power consumption of the Nano. This is 24.7 mA in normal operation and 7.4 mA in sleep mode. If I calculate this over the period of 60 days, I come to 53.28 Wh (watt hours). That seems to me quite a lot?

Is a german page: Stromverbrauch Arduino & Wemos Boards (arduino-projekte.info)

6

Arduino dont seem to consider having a low sleep current in their designs.

For battery life calculations its often easier to just think in mAhr. A set of good quality AA batteries would have a capacity of circa 2800mAhr.

So an Arduino with a 'sleep' current of 7.4mA would last;

2800/7.4 = 378hours = 16 days.

Its not difficult to build an 'Arduino' that has a sleep current of circa 3uA with RTC wakeup.

1 Like
7

I think that´s the better approach. Nevertheless, I need a voltage of 5-12V or I am wrong?

8

If I use a power bank that has a voltage of 5-12V. So 1.5A at 12V delivers and has a capacity of 10000mAhr.

Can the calculation then be made:
10000/7.4 = 1351.3hr = 56 days

Can I assume that my device needs less than 1.5A?!

9

For a Nano Every, perhaps you are correct. It's not a good choice for this project. A better choice would be a 3.3V Arduino compatible board designed for low sleep current.

Is it required that you use Nano Every?

Where will the data be stored?

10

Not really.

The powerbank itself will have a quiescent current, which you need to account for.

And a lot of power banks have a low current cutoff, so may switch themselves off when the drawn current is as low as 7.4mA.

11

No it isn´t fixed. I´m still looking for the right controller. So far, only the data shoud be recorded and stored (for example SD-Card).

So I found other Controller for example the WeMos D1 mini with sleep mode 0.17mA and normal Mode 70mA. But it is a 32Bit Controller

12

That should not matter.

Consider a SparkFun ProMini (8MHz/3.3V version); uses the good old 328P and after removing the LED the processor is the only power consumer.

13

Wemos mini is ok but not great for long battery life projects. My weather station is powered by a 2,400mAh 18650 li-ion battery and lasts around 8~9 weeks between charges. It consists of a wemos mini, which sleeps for 15 minutes, transmits data to a remote server in around 5 seconds before going back to sleep. The current consumption you mentioned above is accurate. However, because some of the sensors require constant monitoring (anemometer, wind vane, rain gauge) is also has an attiny85 which consumes a constant ~0.5mA. Without the attiny, the battery life would be much longer.

When I get around to replacing the weather station, I will do things differently, having learned better ways in the ~5 years since I built it. I will use atmega328 because I know know how to get that to run on ~20uA, even when monitoring sensors continuously. The attiny won't be needed. I will also switch from wi-fi to LoRa which is lower power and has far greater range.

14

Thanks for Help. I prefer the SparkFun ProMini // Arduino Pro Mini 3.3V 8Mhz. In SleepMode it has 1mA - 50uA, in Normal Mode up to 8mA.
With this Controller and an industrial cell (18650 - 3500mAhr) I will bridge 60 days.

15

That sounds a little high for 18650. I would expect closer to 2500mAh. For 3500mAh I would imagine a 21700 size would be needed.

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