Autos: battery change

Self-tutoring about car batteries and changing one: the tutor mentions a recent event.

I checked both cars’ batteries late last spring. Car1’s battery was, I believe, over 12.6. Car2’s battery was showing a voltage of around 12.5, which I knew meant it would need replacing soon. However, Car2 wasn’t complaining about the battery yet, and neither did the diagnostic computer when I plugged it in.

We drove Car2 down to Vancouver and back a few weeks ago without any problems. However, the engine light came on. When I plugged in the diagnostic, the complaint was about the thermostat. Yet, the engine light only came on sometimes, so I wasn’t in a hurry to change it. I bought a new thermostat last weekend and yesterday evening went to start Car2 again, to see if it would complain about the thermostat. It if did, my plan was to change it.

However, Car2 barely started. I plugged in the diagnostic computer; sure enough, it was complaining about both the thermostat and the battery.

With the battery that weak, I knew I had to replace it while the car would still start. I did some research and headed out in the evening, grateful to God that Car2 made it to the store. I picked up the appropriate battery there – that’s another story.

Having loaded the battery into Car2, still in the store parking lot, I sat back into the driver’s seat, ready to head home. That’s when I noticed Car2’s clock was wrong. That’s how quickly a battery can deteriorate, I suppose, once it’s dying. Thankfully, it did start, though, and I drove home without incident.

Back at home, I changed out the battery, then took it for a test drive. Everything worked fine; moreover, it no longer was complaining about the thermostat: the engine light never came on. However, my wife will need to reset Car2’s clock; I’ve never been good with that sort of thing. Thankfully, she is.

It might go to show: when a car’s battery gets weak, other things it tells you might be suspect. Moreover, a weak battery might perform fine when the temp is 26C, but show its weakness at 16C.