Autos: battery testing: one story

Self-tutoring about autos: the tutor mentions an experience with battery testing.

The following is according to my understanding.

As I’ve oft mentioned, I don’t have a car, but my wife and son both do. Over the Christmas holidays, one might do such things as test batteries, etc. After all, the winter season is just beginning, technically. Therefore, I decided to test the batteries in both cars. I mention the idea of a load test in yesterday’s post.

The battery in my son’s car passed with flying colors: resting charge, running charge, and load test all turned out great. The one in my wife’s car, which I would have expected to test at least as well, actually turned out worse: in particular, its resting charge was only about 12.15V. Somewhat interestingly, it fared well in the load test as well as the running charge test. Yet, with car batteries, one might be a little anxious about a resting voltage of only 12.15V; 12.6V, for instance, is much better.

However, my wife’s car is often used for short trips, which as I understand, isn’t good for a car battery. I decided to take it out on the highway, get the revs up, then retry the resting charge: perhaps the battery would be rejuvenated.

Back from the highway drive of around 15 minutes, I turned off the car. Next, I put the headlights on for a couple of minutes to settle the battery down. I turned off the headlights, then measured the battery’s resting voltage: 12.17V, at first. I’d hoped for more.

Yet, as I held the multimeter probes to the terminals, the voltage rose. Eventually, it reached 12.4V, then blinked back and forth between 12.41V and 12.39V. I suspected, at that point, I’d seen the end of the voltage rise.

Well, 12.4V, as I understand, isn’t too bad. Moreover, for the battery to be able to bounce back from 12.17V to 12.4V, I think, testifies that it’s still got some heart. As I mentioned, it passed the running charge and load test fine; it’s just the resting charge that posed a question.

For now, I’ll keep on eye on it, as they say. If there’s news, I’ll likely mention it in a future post:)

Source:

batterystuff.com