Edmonds Auto Repair

A weak battery and a weak alternator can make a car act the same way. You turn the key, the starter hesitates, and the lights look a little dim. Many drivers replace the battery first, only to have the new one go flat a few days later. The reason is simple: the battery stores energy, but the alternator makes it while the engine runs. When the alternator falls behind, the battery takes the blame. Why a Bad Alternator Mimics a Bad Battery Both parts live in the same electrical loop, so their symptoms overlap. A worn alternator does not keep the battery charged, which leaves too little reserve for the next start. Short trips make this worse because the alternator has less time to replenish what starting the engine used up. Cold mornings add load from the heater, window defogger, and seat warmers, so the battery drains faster and voltage dips. It feels like a tired battery, but the charging system is the root cause. Common Signs the Alternator Is Struggling ... read more