Slow Cranking on a Cold Morning: What Winter Does to a Battery Here

What the cold actually does

A battery makes current through a chemical reaction, and that reaction slows down when it gets cold. Your oil thickens on the same morning, so the starter has to work harder to turn the engine over. Less available power, more work asked of it.

A battery with plenty left in it handles that fine. One that is three or four years in does not. Nothing failed overnight. The cold just found it.

The valley makes it worse than the thermometer suggests

Cold air settles on the floor of the valley and sits there. During an inversion the coldest air in the region is the air your car is parked in, and it stays that way for days instead of burning off by noon.

Cars parked up the benches get a second problem. You start cold, then climb, with the blower and the rear defroster both pulling before the alternator has caught up.

What we check before we sell you a battery

• • Load test A battery can read twelve volts at rest and still collapse the moment the starter pulls on it.
• • Charging output If the alternator is not putting back what the starts take out, a new battery goes flat too.
• • Parasitic draw Something staying awake after you lock the doors will kill a healthy battery in one cold week.
• • Terminals and grounds Corrosion and a loose ground cause plenty of no-start calls that need no parts at all.

Slow cranking is not always the battery. We test the battery under load, then look at what is charging it and what is draining it while the car sits.

Getting to you in the cold

We work outside in it. Most no-start calls are finished where the car is parked, in a driveway or a work lot, and you do not have to stand out there with us if you can leave the keys.

Give us the grid numbers for where the car is and we can plan the run. Same-day service is normal in winter, though the first hard freeze of the season is our busiest week.

Frequently Asked Questions