# how to make 14v laptop battery level indicator with arduino.

I want to sense 14v laptop battery charge level like 80% 90% with arduino. I want to sense atleast 0% and 100% with arduino.

Sami5529:
I want to sense 14v laptop battery charge level like 80% 90% with arduino. I want to sense atleast 0% and 100% with arduino.

Use a voltage divider to drop the voltage at the Arduino to 5V, and then it's NO different from any other battery that you want to monitor the voltage of.

PaulS:
Use a voltage divider to drop the voltage at the Arduino to 5V, and then it's NO different from any other battery that you want to monitor the voltage of.

You mean that by regulator i shall drop 14v to 5v and then by use of voltage divider i shall measure the capacity based on voltage?

Sami5529:
I want to sense 14v laptop battery charge level like 80% 90% with arduino. I want to sense atleast 0% and 100% with arduino.

Lithiums have very flat discharge curves so hard to detect state of disharge
Can you define the percentages? what is 0% in volts?
And how do you intend to connect to the battery? Laptop batteries are normally pretty much enclosed.

To "sense" voltage with an Arduino is easy, work out highest possible voltage under any conditions, build (Google) Voltage divider and use two resistors to build a divider that will step say that max voltage to 5VDC Tap the center point out to an Analog input of the Arduino and write your desired code, there is an example called read analog voltage in the examples that is a good starting point.

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

Sami5529:
You mean that by regulator i shall drop 14v to 5v and then by use of voltage divider i shall measure the capacity based on voltage?

No, do not use a regulator, just use two resistors as a potential divider between the battery and the Arduino.
The gnd of the Arduino and the battery must be connected together.