Battery or alternator? A jump start often shows which one failed. The battery sends power to the starter. The alternator recharges the battery while you drive.
If the car starts after a jump and keeps running, the battery is usually the problem. If it dies soon after, the alternator likely isn’t refilling it.
Other signs help too:
- Battery: slow cranking, rapid clicking, or a battery that’s three to five years old
- Alternator: dash lights that pulse brighter and dimmer, or a whine when you rev
- Either one: a battery warning light on the dash
One Canadian shop says a good charging system reads 13.7 to 14.7 volts with the engine running. Below 13 volts points toward the alternator.
A battery that goes flat overnight but tests fine may have a drain, like a dashcam.
Don’t count on a weak alternator to get you home. The car runs only as long as the battery has a charge. It can stall while you drive.
Get both parts tested before you buy one. For prices, read our guide to car battery replacement cost in Vancouver.
Service desk The full guide
Car battery replacement cost in Vancouver: the published prices, what a quote covers and how to compare quotes.