Managing nRF52832 with a 3,7V Li-Po-battery

RE: Managing nRF52832 with a 3,7V Li-Po-battery

codebreaker176 — Wed, 19 Aug 2020 18:03:40 GMT

Hi,

Even I am using the same,

Can you please tell me how long does it take to charge this battery.

RE: Managing nRF52832 with a 3,7V Li-Po-battery

Jørn — Fri, 19 May 2017 09:21:06 GMT

Hello Ray Breslin

Please note the ADC's of the nRF51 and nRF52 do differ in a few aspects, so be sure to read through the SAADC section of the nRF52832 product specification here.

You can find a SAADC example in the SDK->peripheral->saadc folder (SDK11 and later). The example you refer to is outdated as it was made for SDK 6, which was released several years ago. I recommend you look at the examples of newer versions of the SDK.

For the resistor divider you will need to set the acquisition time (described in the PS linked above) to a suitable interval, based on the total source impedance of your divider.

Another relevant read is this blog post on battery voltage measurements with the nRF52

Best regards

Jørn Frøysa

RE: Managing nRF52832 with a 3,7V Li-Po-battery

Ray Breslin — Tue, 16 May 2017 09:36:16 GMT

One thing that I thought about is the usage of a 3V-step-up-/step-down-regulator in order to handle the voltage-regulation for the 3,7V-LiPo-battery in order to power the nRF52832 and optional sensor components.

Question here is now wether it is possible to measure the actual voltage-level of the LiPo-battery by using a GPIO of the nRF52832 - considering that the voltage connected to that GPIO is reduced with a proper diode.

Is that realistic?

[Edit #1:] Seems like Turbo J already suggested the usage of a voltage-divider here - now the only question that remains is on how to readout the voltage-level from that GPIO?

[Edit #2:] Now after a quick check of all the other provided links for a designing a voltage-divider-circuit, the nRF51-manual (which should be pretty close to the nRF52-manual) and also some code-example for ADC-measurements there are no more questions left so far! (Ill check back when I ran some tests with the hardware!)

[Edit #3:] In order to have the ADC-example working, do I need explicitly need that nRF51 DK or nRF52 DK? Because I need to run it on my custom-board and I am not sure on how to handle the ADC-pins...

RE: Managing nRF52832 with a 3,7V Li-Po-battery

Ray Breslin — Mon, 15 May 2017 16:28:03 GMT

Oh thank you very much for that clarification... learned something new there. Then it is obviously even more essential to work on a proper voltage-regulation-concept!

RE: Managing nRF52832 with a 3,7V Li-Po-battery

Turbo J — Mon, 15 May 2017 15:43:26 GMT

If you connect a component that draws current, then the voltage-level will immediatly drop from 4,2V to 3,7V while being in operation-state (open to corrections here!).

Nope:

As you can see, it can take may hours for a LiPo to reach its 3,7 volts. This is an NRF52 setup consuming about 20mA altogether, powered with an 1000mAh LiPo cell. It was already running for some hours before the recording started.