Hey, simple stupid question, but can someone tell me what an alternator does? I have a laptop hooked up to my car through the lighter plug, and it sucks the battery hard, it killed my battery and I had to get a new one. They told me to look in to getting an alternator. Does this just add juice to the ciggerette plugs?

You may need a larger capacity alternator possibly. If you keep going through batteries. If one battery has gone bad it could be the battery was defective. If it keeps happening it could be your charging system possibly thge alternator. You charging system may not be ableto keep up with all the accesseries that you are using.
Police cars have extra high output alternators to handle allthe radio equioment ,lights sirens and such and you may need the same.

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1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T

You don't need a larger alternator to handle a laptop computer connected to the cigarette lighter. A laptop would only draw a few amps.

It is most likely coincidental that you experienced electrical problems with the connection of the laptop unless there is a short in the laptop power cord or charger.

The alternator simply recharges the battery when the engine is running. To check your alternator, simply start the engine and put a DC Voltmeter across the battery terminals. You should read around 13.5 volts. If you're reading only about 12 volts, the alternator is not charging.

Good luck,