The signs
Any one of these is worth paying attention to. Two or more together usually mean the battery is close to the end.
- The engine turns over slowly, most noticeably first thing in the morning.
- You hear rapid clicking when you turn the key or press start, and the engine doesn't turn.
- The headlights and dash lights dim while the engine is cranking.
- The battery warning light comes on.
- Small electrical oddities: a clock that resets, windows that move slowly, a radio that forgets its presets.
- The car has needed a jump start more than once in a few weeks.
- The battery case looks swollen, or the terminals are crusted with white or blue-green corrosion.
Why heat is harder on a battery than cold
Cold weather gets the blame, because a cold morning is when a weak battery finally refuses to start the car. The damage usually happened months earlier. Heat speeds up the chemical wear inside a battery and dries it out, and a DFW summer full of 100-degree afternoons does a lot of that wear.
Most car batteries last somewhere between three and five years. In a climate this hot, plan on the shorter end of that range.
When it probably isn't the battery
If the lights are bright and steady but the engine won't turn over, the starter may be the problem. If the car dies while you're driving, or the battery light comes on with the engine running, the alternator is the more likely cause.
A jump start won't fix either of those, and neither will a new battery. Have a repair shop look at it.
What to do about it
If the car still starts, replace the battery on your schedule instead of waiting for it to choose a bad moment. A battery more than three years old that shows any of the signs above is worth replacing before the next cold snap.
If the car won't start, a jump start gets you moving, and the driver can tell you whether the battery looked likely to hold the charge. If the battery is swollen, leaking or smells like rotten eggs, don't try to jump it yourself. Call for help.
Common questions
Usually three to five years, and heat pushes it toward the shorter end. If yours is past three years and showing any of the signs above, replace it before it leaves you stuck.
It gets you moving, but it can't bring back a battery that no longer holds a charge. If the car needs another jump within days, the battery needs replacing.
Every car draws a little power while it's parked. A healthy battery covers that easily, but a weak one runs flat. A battery that dies after sitting was often already near the end.