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6 years, 8 months ago.
How to measure battery percentage
Hi All,
I am pretty new to mbed and also new to electronics in general. I am trying to develop a small application that checks the battery percentage and based on that it will make an HTTP connection to our server. I am using an MTQ-H5-B01 dragonfly on a UDK2 board, and a 3.7v Lithium Polymer battery.
So my questions are:
1) How to get the voltage and measure the battery percentage?
2) If measured, how to know if voltage measured is coming from battery or direct plugin?
I have checked the below links but they are not providing required results:
https://docs.mbed.com/docs/mbed-os-api-reference/en/5.2/APIs/io/AnalogIn/
https://developer.mbed.org/users/tylerjw/notebook/battery-voltage-monitor/
Regards, Dawit
1 Answer
6 years, 8 months ago.
Dawit,
It's almost impossible to accurately predict battery percentage from voltage alone.
This stack exchange article is a good introduction:
https://electronics.stackexchange.com/questions/18818/reading-a-li-po-batterys-remaining-charge
Cheers, Nick
To mesure the battery-voltage you need some kind of reference-voltage, e.g. a linear-regulator or the supply of the mcu, then you can compare the two voltages (via analog-in and a voltage-divider). The plug-in-detection could be managed with a digital-in-pin connected to the supply-line of the charging-circuit (pay attention on on the maximum input-voltage and use a voltage-divider is needed). Some battery-charger-ICs provide informations about the battery, I don't know your board, maybe you can use something like that.
posted by Theo Bestenlehner 06 Aug 2017