Battery life on nrf52840 using meshing.

RE: Battery life on nrf52840 using meshing.

Hung Bui — Mon, 17 Feb 2020 09:19:34 GMT

Could you clarify are you really using mesh or you are just using Bluetooth Low Energy (start network, point to point, one central node and multiple peripheral node) ?

If you are using mesh, which technology are you using ? How many node in the network ?

Could you explain what is the "Open Alarm" and "Close Alarm" ? Why the duration is 24 hours and 280s ? Even if the duration of the alarm is 24 hours, you don't need to transmit data all the time, continuously for 24 hours, correct ?

Please describe in more detail the "Long Range" mode you are using, what radio configuration do you have ? Which output power ?

RE: Battery life on nrf52840 using meshing.

Marciano-PL — Fri, 14 Feb 2020 18:16:41 GMT

If your tx device is not expected to ever need to pass along messages for another device, it would be quite viable to employ the LPN example code. When LPNs go to sleep, they turn off the radio rx that mesh requires, meaning your sleep current could be below 10µA. You could also just deactivate mesh on your device manually if you don't need the friend node capabilities. Here is a ticket showing how to turn off mesh. https://devzone.nordicsemi.com/f/nordic-q-a/57450/reliably-disabling-mesh-stack-quickly-for-low-power

I would definitely consider reading into the friend + LPN features because they sound like they would accommodate your project well.

RE: Battery life on nrf52840 using meshing.

Robbylaw — Fri, 14 Feb 2020 17:06:23 GMT

Ok I have a transmitter mounted to a garage door using 2-3.6v batteries in paraelle when door is closed transmitter is in sleep mode when door opens transmitter awakens and send signal to receiver (nodes) . the receiver starts to blink LED lights and make a beeping noise. the distance in range with just one node is about 90 feet indoors then another node further. the receiver nodes are plugged into a usb wall charger and have full power supply at all times. but battery life is way to short. I am not sure what you mean by what feature of bee long range I am using ? we are using the blue nrf52840 chip with long range and meshing. the nodes are not running on battery only the transmitter. and it is in beacon mode.

RE: Battery life on nrf52840 using meshing.

Hung Bui — Fri, 14 Feb 2020 13:20:44 GMT

Could you describe your mesh network ? Which nodes are relay node, what is the communication between them ?

As mentioned by Marciano, relay nodes and normal mesh nodes require main power. You can run a low power node on a battery. But this node can't relay mesh message.

You mentioned that with Bluetooth 5 you have longer range, which feature of Bluetooth 5 you used that improve the range ?

RE: Battery life on nrf52840 using meshing.

Robbylaw — Fri, 14 Feb 2020 01:45:42 GMT

I was only getting 50 feet distance indoors using ble 4 so upgraded to ble 5 and now I am getting 90 feet indoors I did ad meshing just Incase I needed to extend range beyond that but the battery issues are killing me.

RE: Battery life on nrf52840 using meshing.

Robbylaw — Fri, 14 Feb 2020 01:41:30 GMT

Thank you for your reply. When you say meshing not for battery operated devices. My tx is the one with the battery and my rx nodes has unlimited power supply. Does that make a difference? And the tx sleeps when the garage door is closed when Door opens a tilt switch activated the tx which send a signal to the nodes. To better understand my device please have a look garagedoorminder.com

RE: Battery life on nrf52840 using meshing.

Robbylaw — Fri, 14 Feb 2020 01:41:29 GMT

RE: Battery life on nrf52840 using meshing.

Marciano-PL — Fri, 14 Feb 2020 00:57:49 GMT

I'm not sure exactly what some of your weekly current consumption formula means. If you are running the radio the whole time then
2.4Ah / 10.8mA = 222.22h = 9.25days

RE: Battery life on nrf52840 using meshing.

Marciano-PL — Fri, 14 Feb 2020 00:52:35 GMT

Unfortunately I think your numbers are realistic. Mesh requires that you have your radio on at all times, which adds up. Mesh isn't really designed for battery operated devices, unless you can have some devices with an unlimited power source nearby. If this is possible for you, consider reading about low power nodes (lpn) and friend nodes.