My son had to repeatedly jump his Buick’s battery. He finally replaced it, drove it for a day or 2. Now it won’t start at all. It won’t make a sound. No lights. No horn. Nothing.
Checked the connections?
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Because his battery is now dead. He thought that was the problem but it wasn’t. I’d suggest that the alternator has failed and it doesn’t charge the battery. Even if the new battery is dead, it can be recharged but check the alternator and check for a battery drain of some sort. Like a power amp for an aftermarket stereo.
Were there any lights on during those days? because one possibility is a bad alternator. Other possibilities are bad battery cables, bad connections, or a high parasitic drain.
Some more info would help. My guess is a high parasitic drain as that will discharge the battery as it sits.
have the battery tested, but one can assume that a new battery does not go dead unless it is defective or is not being charged by the alternator. I suspect the alternator.
Your GM vehicle has the side mount battery terminals.
These connections can cause all kinds of problems when messing with the battery terminals.
Replace the positive battery cable assembly.
Tester
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I had one where the rubber covering had deformed and prevented contact after being reconnected, exacto knife to the rescue.
Additional info: I tried to jump the car with my truck. After attaching the cables, still nothing. Won’t charge at all. Still no lights, horn, dash lights, nothing.
Gee?
Wonder if a poor battery connection might cause that?
Tester
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I agree.
I think you need to get it to someone knowledgeable about starting and charging systems for a diagnosis. They’ll have the knowledge and equipment to check the connections, test the battery, test the alternator, and perhaps a few other things… like for that parasitic drain that others have mentioned.
The old battery may have cause the alternator to fail. Sometimes the only solution is to replace BOTH the battery and alternator at the same time.
As others have stated, the first thing you need to do is make sure the battery connections are clean. If they are good then you need to check for power getting to the fuse/relay panel under the hood. Use a test light probe to verify where power is getting to. Power for the ignition switch comes from that panel under the hood so verify that the fuses are okay inside that panel. There is usually a smaller wire that ties to the main battery cable that supplies power to the panel under the hood. It could be a fusible link which looks like a normal wire. They can go bad but you can’t tell that by just looking at it. Testing for power at each end with a test light will show up the problem if that is the case. Once you get the car running you should have a shop check out the charging system.
How can that happen?
Tester
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Alternators are designed to supply the electrical needs of the vehicle and maintain the battery. A totally dead (or bad) battery simply overloads the alternator and causes premature death.
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I beg to differ, that’s why alternators have voltage regulators to prevent just that, besides maintaining the needed voltage while the car is running.
Are you kidding me!?
Anybody who knows anything about an alternator charging system knows a bad battery can kill an alternator.!
Where have you been in the last 60 years?
Tester
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I think Tester is probably correct, the battery is ok but it isn’t connected to the rest of the car for some reason, most likely the cable is frayed (either in the + or - side) and has broken at the connector, or there’s a fuse that has blown. The alternator is probably ok too.
Suggest to ask your shop to measure the battery voltage. Try it with the headlight turned on too, even tho they don’t work. If it is 12.6 volts or so, headlights switched on or off, probably nothing wrong w/the battery or the alternator.
Tester is also correct to not attempt to charge a totally dead battery using the alternator. That’s what battery chargers are for.
A proper working alternator will not be harmed by charging a “dead” battery. Once the engine is running the maximum voltage output is ~14.5V. The voltage regulator will prevent the alternator from putting out a higher voltage. Anything much higher and for a prolonged time can cause electrolytes to start boiling and drying out the battery.
Under normal driving conditions the voltage output will be between 13.0 and 14.5 volts and completely depends on what accessories are turned on. Someone with a huge amplifier, ten kids with an I-phone plugged into the cigarette charger, A/C on the highest setting, all lights and high-beam on and the alternator will produce a steady maximum of 14.5 V. Does it ruin the alternator? No
The alternator does not know what is being charged, it simply puts out the voltage needed or requested by the ECM to drive all these accessories and engine.
This said, if I an alternator is always putting out the maximum voltage, I agree that it can (not will) shorten its life.
I have a always heard that that the alternator could not charge a completly dead battery but if the battery has small charge then the alternator could complete the charge.