Monitoring voltage of a second battery

I would like to measure the voltage of a second 12V aux battery in addition to the main battery.

I have no real idea where to start. I think I need an ADC and should be able to connect it to the GPIO directly. But other than that I’m kinda lost.

Has anyone experience with a similar Project and can help me out? I am interested in HW and SW solutions.


Hi Thomas,

Interesting project. I think you are on right track. I would connected a simple ADC to the I2C port on the AutoPi. You can get ADC in HAT format from most Rasperry Pi shops on the internet. It will most like fit directly on top of the GPIO pins.

Once connected you need to write a small piece of code to interact with the ADC. I recommend using the custom code modules for this.

Let me know how it come along and maybe we can provide you with some pointers if you are stuck.

Best of luck.

Kind regards,

Hi all,

I am planning of extending the autopi with RV functionality (for which project I am looking for other interested people) … one topic will of course be the “stuff behind the drivers seat” and how to put sensors there but also how to integrate it with the dongle and/or the autopi API…

My thoughts are putting another onboard device (raspberry or esp8266 et al based) and collect data there … and send it eventually to some “on dongle” collector service. I would not prefer WiFi for that as sitting in a cage filled with radio frequency doesn’t sound that appealing to me.

So it would probably be some wire or “on demand” transmission.

Thoughts appreciated.