I have a 4 cell lipo that I want to monitor with the Arduino Duemilanove.
I'am a Arduino noob, but I managed to monitor one cell. This is how I did that...
I used 2x 10K resistors, didn't know how it supose to work, so I just tried. This way I could read 3.71v on the serial. I first tried to use only one 10K resistor, it worked, but the power led on the arduino started to burn, even when it wasn't connected to USB, so I gues the arduino is using it as a power supply somehow. With the extra resistor it didn't. But even with the resistor it is using power. And I gues I need a 4pin on/off switch to turn on and off both the - of the dean plug power cable of the lipo, but also the - on the recharge plug to prevent power loss on storage.
And I used this code...
But I want to monitor all 4 cells at the same time, so I first tried to read the second cell, and arduino displayed 4.94v! I tested it with my multimeter, and it was 7.54v. So it's was in serie, and the next cell and the next were also in serie. This makes it verry hard for me to simply monitor all cells.
I read about voltage dividers, but I gues I need a different divider for every cell :o
My plan was to display all cells on a lcd display. And calculate the total voltage by counting all cells together. But this plan isn't going to work I gues.
Can someone help me with monitoring all 4 cells? And help me with a circuit drawing? I don't know how exactly use a voltage divider, and what code I need for that. Remember, I'am a noob, so every advise must be in noob language.