Read Battery Level with lithium battery and nRF52832

RE: Read Battery Level with lithium battery and nRF52832

EeChin — Thu, 30 Jul 2020 06:36:46 GMT

Greetings,

Thank you for the assistance. Just an update: I manage to make it work!

For future readers: I realised in the schematics that a step down has been implemented so there is no need for me to do that anymore. As for battery level percentage, I use a power supply and alter accordingly to know whats the highest and lowest voltage needed for the device to power it up. It turns out that the interpolation is quite similar to the example ble_app_proximity battery calculator function so I followed.

Best Regards,

Ee Chin

RE: Read Battery Level with lithium battery and nRF52832

haakonsh — Fri, 24 Jul 2020 11:06:09 GMT

[quote user="EeChin"]Is there any formula/conversion to follow?[/quote]

That depends on the battery. I suggest you do some research, keywords:
* Battery fuel gauge (app notes)
* Battery level
* Battery indicator
* etc.

I'm going on vacation for a week, but I'll assign your case to another Tech Supporter.

BR,

Håkon Holdhus

RE: Read Battery Level with lithium battery and nRF52832

EeChin — Fri, 24 Jul 2020 01:53:19 GMT

Hello, please ignore my previous message as I realised that there is already a divider in place as shown in the schematics.

My question now is, to calculate the battery percentage level, how do we make use of the millivolts (from the adc_result_in_milli macro) ? Is there any formula/conversion to follow?

Please reply. Thank you.

RE: Read Battery Level with lithium battery and nRF52832

EeChin — Thu, 23 Jul 2020 09:10:07 GMT

Hello thank you for the kind reply.

I am a beginner in this so pardon me for asking stupid questions.

Does the divider refer to a piece of hardware?

In order to use the battery percentage calculator in proximity example: 3v to 2.1v AND not having to use the divider but directly calculate, which kind of battery shall we look into?

Thank you for reading this. Hope to hear from you soon.

RE: Read Battery Level with lithium battery and nRF52832

haakonsh — Thu, 23 Jul 2020 09:04:22 GMT

[quote user="EeChin"]May I ask what is the common power supply that people use for nRF52832?[/quote]

1.7 V–3.6 V supply voltage range.

[quote user="EeChin"]When/where shall we implement the divider in code?[/quote]

What do you mean?

[quote user="EeChin"]how do i know which pin shall i use?[/quote]

For the battery voltage sensing you can use any of the analog input pins.

RE: Read Battery Level with lithium battery and nRF52832

EeChin — Thu, 23 Jul 2020 05:00:49 GMT

Hello,

an additional question, how do i know which pin shall i use? please reply and help me thank you.

RE: Read Battery Level with lithium battery and nRF52832

EeChin — Thu, 23 Jul 2020 01:49:27 GMT

Thank you for the reply.

May I ask what is the common power supply that people use for nRF52832?

When/where shall we implement the divider in code?

Please reply, thank you so much.

RE: Read Battery Level with lithium battery and nRF52832

haakonsh — Wed, 22 Jul 2020 15:49:27 GMT

[quote user="EeChin"]How do i see whats the supply voltage on VDD pin? [/quote]

It's up to you to specify the power supply for the nRF device.

[quote user="EeChin"]Also what's the different between the AIN pins and VDD?[/quote]

VDD = power supply pins, AIN = Analog INput.

[quote user="EeChin"]I am not sure which part is the divider, is it (2 M/(0.8 M+2 M))?[/quote]

correct, see https://learn.sparkfun.com/tutorials/voltage-dividers/all for basic theory.

RE: Read Battery Level with lithium battery and nRF52832

EeChin — Wed, 22 Jul 2020 14:34:24 GMT

How do i see whats the supply voltage on VDD pin? Also what's the different between the AIN pins and VDD?

I am not sure which part is the divider, is it (2 M/(0.8 M+2 M))?

RE: Read Battery Level with lithium battery and nRF52832

haakonsh — Wed, 22 Jul 2020 12:54:06 GMT

[quote user="EeChin"]What does VDDnrf mean?[/quote]

The supply voltage on the nRF52's VDD pin.

[quote user="EeChin"]But how to exactly implement the divider?[/quote]

The blog post is quite detailed, I don't know what questions you have not gotten answered yet. What exactly do you need help with.

RE: Read Battery Level with lithium battery and nRF52832

EeChin — Wed, 22 Jul 2020 11:17:42 GMT

Hello, thank you for the reply.

Can I ask what do you mean by 0v - VDDnrf? What does VDDnrf mean?

I have read this: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/measuring-lithium-battery-voltage-with-nrf52

But how to exactly implement the divider?

Please reply. Thank you.

RE: Read Battery Level with lithium battery and nRF52832

haakonsh — Tue, 21 Jul 2020 15:28:27 GMT

You need a voltage divider in order to reduce the analog input voltage into acceptable levels, 0V - VDDnrf.

The resistance of the divider cannot exceed 800kohm.