Battery Testing: Our Team would like to share our downloadable study with your team!

[Analog]

Originally Posted by Ether

I enjoyed reading your paper. Nice work.

I have one question, one observation, and one request.

Question:

When doing the high current discharge test, did you allow the load resistor(s) to cool to the same starting temperature before performing each test?

Observation:

Figure4 on page 14 looks strange. The voltage at 30s at 200A is lower than the voltage at 15s at 400A.

Request:

Would you be willing to provide more in-depth detail about the design of your dynamic loader and logger?

Dear Ether,

We allowed time for the load resistors to cool between tests. We also had a fan blowing across the resistors during the test.

Figure 4 (from SAE J537) is showing the non-linearity of battery discharge based on load current. This was the reason we tested at two different discharge currents. The curves make sense, as each is a stepped based on the current load, i.e. the larger the current, the lower the output voltage at that current over time, since the internal resistance is making up the rest of the cell voltages.

The team plans to do a "makable" on the battery logger and dynamic loader, hopefully as a summer project once the maelstrom of competition season is over and we get a breather. We specifically kept it out of this report because it would have shifted the focus from strictly analyzing batteries and ranking them.

Thanks again for your feedback, we really appreciate your comments!

-Bob