Reading a 12.62 Volt battery with a voltage divider on an UNO

[Billduck1302]

I have a 12.62 Volt Lithium battery (4S). The voltage goes thru a 5:1 voltage divider to AN0 on the UNO. It consistently uuder reports the voltage. (See photo) For the component, a potentiometer, I am wondering if settings for the pot need to be tweeked. From the photo, the UNO is saying the voltage is 11.18. The Voltage divider
If the attatched photo does not come thru, there are 2 connections for the Voltage to be measured. and I have connected the Signal wire to AN0 and output (-) wire to the analog input (-).
Thanks in advance.

Link to divider

https://www.ebay.com/itm/323881639189?_ ... BMiM_q-PNm

[stefan.erni]

Hi Billduck1302

I suspect the link goes to the wrong module.
Perhaps you could post a schematic. Actually, you only need two resistors.

82 kΩ / 9,1 kΩ → divider 0,0999 and 0,165mA

91 kΩ / 10 kΩ → divider 0,0990 and 0,149mA

This requires a little power from the battery. You can also use higher resistance values.

910 kΩ / 100 kΩ→ divider 0,09901 14,85μA

wrong link?

2026-01-09_08-41-24.PNG (259.63 KiB) Viewed 170 times

[Billduck1302]

Minute 2:14 in this Youtube explanation.
https://www.youtube.com/watch?v=FaoKzi7tgME&t=280s

[stefan.erni]

Hi Billduck1302



I found the modul:

2026-01-09_15-59-57.PNG (230.76 KiB) Viewed 142 times

And what is used in the modul:

2026-01-09_16-01-59.PNG (361.17 KiB) Viewed 142 times

There is a command "map" used in the software,

2026-01-09_16-31-10.PNG (175.05 KiB) Viewed 142 times

I guess that's the same as the map component in Flowcode.

2026-01-09_16-20-14.PNG (9.59 KiB) Viewed 142 times

I hope that helps a little.

I haven't used the map component yet, but I will be using it soon for my project.

[chipfryer27]

Hi

The map component is very easy to use and I think medel35 first created it years ago before it became a component.

Regards

[medelec35]

Hi
The map component is very easy to use and I think medel35 first created it years ago before it became a component.

Regards

Wow chipfryer27 , you have a good memory as that was a long time ago.
Yes, I created the map component based on the Arduino version so people moving from Arduino IDE to Flowcode will be used to the way it works.

[chipfryer27]

Hi Martin

it was such a useful component it immediately stuck in my mind, which is no small feat, especially as I firmly believe guys have a fixed amount of memory and can only remember so much. If full and we want to remember something new, then we must forget something else.....

I make a point of not remembering things, mainly because if my theory is true, I don't ever want to forget Halle Berry in a catsuit.... Greatest movie ever....

Regards

[Billduck1302]

I am not seeing the MAP function in Version 11.

[medelec35]

Hi Bill.
Within Components ribbon, make sure Show Components on the far left is set for 2D & 3D.
Then click on the magnifier next to Show Components and enter map.
The Map Function can also be found within Components > Math > Calculation.

I don't ever want to forget Halle Berry in a catsuit

Oooh, yes, we can't ever forget that in our increasing age.

[Billduck1302]

Thank you. This interplay is what makes the Forum so great.