How to measure remaining LiPo battery?

Hi,

I am developing a system where the nVidia Jetson will be on board of a autonomous vehicle. I want to achieve an accuracy measure of the remaining battery using the nVidia Jetson. I need it to take some previous decisions on the board and then turn off the system.

I have already used some LiPo battery indicators for other purposes (the typical buzzer or led indicator shown in the wiki) but they have poor accuracy and also I do not know how to read those indicators with the nVidia Jetson.

I will use 3s or 4s LiPo batteries, 5200 mAh capacity, and 10C discharge. I will have connected some other hardware appart from the board (brushless motors, servo motors, controller, rc receiver, camera…)

Is this possible? What would be the best way?

Thanks to all, Juan.

Are you planning to drive the motors directly from Jetson or will you have a separate MCU for those? I’m using a separate MCU in my project and with that it’s easy to drop the LiPo voltage using a voltage divider and then use an ADC to measure the voltage level.

There probably are ICs that can do something similar and you could hook that to the Jetson with e.g. I2C.

You can measure voltage by INA219 or INA226 i2c chip;

http://www.jarzebski.pl/arduino/czujniki-i-sensory/cyfrowy-czujnik-pradu-mocy-ina219.html
http://www.jarzebski.pl/arduino/czujniki-i-sensory/cyfrowy-czujnik-pradu-mocy-ina226.html

Sorry, entries are Polish :)

Kulve, I will use some PWM outputs of the Jetson to control the motors. The brushless motors are powered through ESC (Electronic Speed controlers),and the servos by constant 5 V. Then yes, I am using a separate MCU if that means not powering the motors directly from the Jetson. In the case of the 5 volts I will take some 5 volts output from the Jetson (options at the end of the page - http://elinux.org/Jetson/Jetson_TK1_Power)

I think I will try with one of the i2c chips that Santyago said. They look great, thank you!

It will take me some time to get it working, but I will post here when done.