function of the alternator

The alternator recharges the battery and supplies power for the entire vehicle while it is running. The life expectancy depends on how it is used, I have seen some alternators run over 200000 miles while others have failed within factory warranty. Cost to replace an alternator varies greatly, I have done some that only took a half an hour to replace while other have required the engine to be removed to even get to the shielding that covered the alternator. .

They are right, the alternator can die at any time or last many years. The working part of the alternator is diodes that can get dirty and fail. Most of the time a thorough cleaning can rejuvenate the alternator if there is no physical damage.

Obviously, the alternator supplies all the electricity the car uses..... What's the life expectancy of an alternator? Well, that depends on how the car is maintained; especially the battery. When a battery is worn out and should be changed, it makes the alternator work harder to recharge a battery that is slower to take a charge or doesn't have the ability to get fully charged. Most batteries in newer cars last three to five years, and many people try to extend the battery life to save money on replacement, and that might be an extra year or more. It's that damaging attempt to extend the battery's life that's the hardest on the alternator, and that's usually why an alternator lasts fifty-thousand miles, rather than two-hundred-thousand miles..... Now, compare the cost to replace a battery, around a hundred bucks, to the cost to replace an alternator, around $500 or more.