Dear friends,
The Figure 1 shows a monitor designed for inexpensive circuits powered directly from the battery, without an intervening voltage regulator chip. The monitor requires only a comparator, a voltage reference, four resistors, and a capacitor. When the battery voltage is greater than the design threshold, the comparator output is high. When battery voltage drops to a certain level set by 10k pot, this simple battery monitor circuit energizes a LED. For reading battery voltage in 1 V steps or even steps as small as 0.1 V, we can add any number of additional circuits.This circuit provides LED indication for easy use on modern cars, replacing the ammeter reading which is too complicated.
I'm a teacher with basic knowledge in electronics. My experience is really on programming. However, I'm supporting a group of students in a project to build a simple battery charger using a solar panel. One of the students is familiar with Arduino. He decided to use the board to monitor the battery charge and automatically 'activate' the solar panel.
Simple Battery Monitor shows both time remaining and charge percentage at the same time. Time values may vary from values displayed in Activity Monitor. It is due to the fact that Simple Battery Monitor has its own remaining time computation and it adapts to your usage. A simple library for monitoring battery voltage in Arduino projects. Utilizes the 1.1V internal reference of the ATmega328 to accurately monitor battery voltage and current.
He is using a clever association of resistors to create a voltage divider and monitor the charge in the battery. Their design includes a relay to activate the connection between the battery and the solar panel. Here is a diagram of the design we are planing to build.
Simple Battery Monitor Circuit Diagram
We were able to test the battery monitor and it works perfectly. However, now we are going to connect the solar panel and I'm afraid to burn the whole circuit, including our board. We would appreciate any advice on the design. We are using a 6v 2A battery and a 6V 1800mA solar panel.
Battery Monitor Software
As a note, this is a students project. The main idea here is to get them excited about electronics and in solving problems. The circuit isn't intended to work for long periods or to be efficient. It just need to work without smoking.
Thanks,
Marine Battery Monitor
Juliano