Scenario: '98 Camry (2.2L); 117k miles withoriginal alternator and3 year old Interstate battery installed;no known history of starting/charging problems; then, dome lightaccidentally left on for nearly 72 hours straight[:@]; batterybecame discharged enough thatengine wouldn't start; battery was jump-started (off another vehicle's battery);car driven immediately for9 hours on the interstate (minus two 15-minute rest/fuel stops); all starts since that trip have been problem-free.

Has the alternator's remaining lifespan beensignificantly reduced by the lack of proper re-charging of the battery?

How much additional time might I expect to receive from this alternator, given its age (10 years), mileage (117k), and this battery discharge scenario?

Thank you.

 

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No, the primary cause of alt failure is the brushes wearing out. Recharging a dead battery will have nil effect in this area. The alt is designed to put out 70-80 amps much more then is needed to recharge a battery.

 

OK.

Well,why do you think that several different automotive sources claim that the alternator is stressed beyond its designed application whenever it's demanded to fully recharge a fully discharged battery? They specify that the alternator is designed only to "top off" an otherwise mostly charged battery and that, by asking it to do the job of a battery charger (which is specifically designed to fully recharge a fully discharged battery), you're usingthe alternator ina manner far beyond what it was designed to accomplish (although it can certainly do it), and thus, overstressing it and causing it to have a shorter life than it would otherwise have. One source even claimed that the alternator could easily overheat while attempting to fulfill this long, constant (i.e. several hours) demand of re-charging the battery. They say that it's the build up of this heat for this sustained time period is enough to shorten the serviceable lifespan of the alternator.

Do these other sources (e.g. automotive tech. articles on charging systems) not know what they're talking about? Or are they accurate, but just blowing it out of proportion? Thanks.

 

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