I am trying to understand the battery management system, but I didn't find any algorithm for columb counting (or) voltage method or any thing else. can you please share this algorithm's if they are with you (or) please share that information to get that algorithms.

My idea to calculate the State of Charge & State of Health of the battery for CAR(preferably electric), please help me to understand this.

  • \$\begingroup\$ This is anything but trivial. For a demanding application like a car where the pack itself is worth a large amount of money, you are going to look at not only present-time measurements like voltage and temperature, but probably logged history too. \$\endgroup\$ – Chris Stratton Nov 6 '15 at 5:16
  • \$\begingroup\$ How did you do your research? I googled "modelling soc of li ion batteries" and found (among other stuff) this thesis which might be what you are looking for: macsphere.mcmaster.ca/bitstream/11375/15253/1/fulltext.pdf \$\endgroup\$ – 0x6d64 Nov 6 '15 at 7:38

The scope of your question is very large, but I will try to give you an example of a relatively simple setup that you might be able to apply to your project.

My electric battery powered lawn mower has a gauge on it that I would call a coulomb counter and here is how it works:

First I had to install a current shunt in series with the motor on the negative wire after it exited the motor, but before the wire entered the battery. The current shunt is just a piece of metal with a known resistance so that when current passes through it, your gauge can measure the voltage drop and then convert that to a measured current. The gauge also measures the battery's voltage at the same time.

With the voltage and current along with time, the gauge, or coulomb counter can now display the amp hours used, the power being used in watts, along with other measurements such as volage. My particular gauge also has the feature where you can program in the battery's capacity so the gauge can then tell you the percentage of battery used as well. If you wire in the battery charger in the reverse the load and ensure it goes through the current shunt, this gauge can also keep track of where you are with your battery charging in terms of how full the battery is.

By measuring the current leaving the battery along with time, you get a much more accurate method of state of charge reporting for battery versus just measuring the battery voltage, which is not as accurate.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.