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The alternator is frying itself by trying to charge and maintain that dead battery.
Exactly right...... This is akin to trying to fill up a bucket that has no bottom. Pretty soon either the alt or the man is going to wear out from the trying....
Doing that is a good way to say good bye to the diodes in the regulator..... I have seen people get lucky and no fry the bridge, but most of the time that bridge gets toasted.
Not to mention all the other potential problems this could create.
Easier to paste a link than type all the reasons...
Yes they can...... There are tools called load testers.
True. Our load testers were always built into the quick chargers, so in an hour you'd either have a fully charged battery or a hot mess of sizzling battery acid. But even then, we'd juice some up only to have the customer come back later and complain the battery was dead again. In fairness, root cause was probably something else, though.
I originally meant the tech has no way of checking its ability to hold a charge quickly, as in not having to remove the battery from the car. I'm not saying the equipment doesn't exist, but we were never given anything for it.
If the motor runs and continues running fine after a jump start and the jump-start cables are disconnected from the vehicle, then the alternator is doing what it's supposed to do. But if the motor stops right after a jump start when you remove the jump-start cables, then there is a good chance that the problem is with the alternator.
The life-span of a battery usually is around 3-4 years. Sometimes they last a lot longer when a good maintenance schedule is followed. But sometimes a battery is slowly discharged by accessories we leave plugged into the cigarette lighter: leaving any of the lights on (cab, headlight, etc.), or just using battery power when the motor is off to play music, and so on. Sometimes the battery is discharged much rapidly if there is a short to ground on one of the power leads, or a short in any of the vehicle's components.
If the battery is old, the most probably cause is the battery., however.
Bad alternators seem rare to me. I have had to replace maybe three in my lifetime and one was due to overloading it with a big stereo system. I have replaced probably 50 batteries in various cars. Probably more. I had to replace 4 of them this month. I probably abuse alternators because I run big inverters in most of my cars (at least 400 watts, some have 2400 watt inverters). Smoetimes the inverters have 5 or 6 items plugged into them. I have melted lighter plugs feeding inverters (needed to use direct wiring), but not had an alternator go out in at least ten years, probably 15.
The longest lasting battery I personally know of is the OEM nearly 12 year old battery in my Mom's 2001 Toyota Corolla S...
Mom did leave the lights on once and it was stone dead in the morning about 5 years ago.
Other than the one case of user error, the batter/charging system seem to be in a perfect zen state
She drives it less than 75 miles a week, mostly trips less than 5 miles to church or shopping.
That said... your problem could be one of four things.
Defective Battery which is best checked by charging and then load testing.
Defective Charging System which can easily be checked with most Battery Load Testers.
Parasitic Loss which is something constantly drawing current... a friend was always having battery problems and it turned out to be the after market sound system he installed.
User Error in leaving some on... lights, dome light, trunk light etc...
When batteries are near to their lifespan 3 to 4 yrs on cheap type batteries and 4 to 5 yrs on high grade batteries), it's just time to replace them when all the symptoms are present! Also about alternators, with the engine is running, disconnect the battery terminals, if the car doesn't shut down, your alternator is good, but if the car shuts down after a few minutes with the terminals disconnected, your battery has lost it's charge completely and also your alternator needs replacing! Usually a full charged good battery on it's own with a bad alternator can probably run for days before discharging completely. Anyway, most cars has an idiot light or a volt gauge on the instrument panel which indicates that the alternator is going bad!
Do not do this....this is dangerous to your car's electronics and NOT the way to test an alternator.
Do not do this....this is dangerous to your car's electronics and NOT the way to test an alternator.
Electronics? Sorry! I forgot to mention my car is a classic 1979 Toyota Corolla SR 2 two dr coupe without any delicate electronic gadgets to be concerned about! She's still running pretty well ever since I bought her in 1999! She has been well pampered all these years
Last edited by Art2ro; 11-29-2012 at 02:06 AM..
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