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Discussion Starter #1
I've been debating what happens when you swap a higher capacity alternator for the OEM ones in our cars. Specifically, I want to add heated seats and other electrical use items to my Benz, and was looking to upgrade to an 80 amp or higher alternator.

The OEM ones, if memory serves, are 40 amps.

If I install a higher capacity alt, will the unused current be dissipated as heat? Be fed to the battery?
 

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Electricity and plumbing have a lot in common. Just think of it as adding a larger tank of water to the system. Your components will take what they need, and you won't 'run dry' as easily.

I'm oversimplifying, but it gets the idea across. Just make sure all your wires are in good shape, and the connectors/connections are clean and tight. You'll be fine, unless you try to have one component that draws too much current. But unless you're trying to install an insane stereo system, or lights capable of igniting innocent bystanders, you shouldn't have to worry.
 

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Unless you want to burn up the factory electrical system your are going to need a fuse box, relayed with a ignition hot. Then you can add a higher amp alternator without a problem and run all of the heated seats and accessories you want.

But the factory wiring is not going to take that amount of additional current draw.
 

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Discussion Starter #5
Well, I figured any electrical appliance I add would be fuse protected as part of my install. Is this to say that a higher amp alternator will burn out the factory wiring throughout the car?
 

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Well, I figured any electrical appliance I add would be fuse protected as part of my install. Is this to say that a higher amp alternator will burn out the factory wiring throughout the car?
Just on the circuits you try to draw power from.

Adding a 40amp fuse behind a 30, does nothing but pop the 30.

Now if the seat heaters pull 50amps and its a 30 amp circuit you are trying to draw the power from, what happens to the fuse? And when you try a higher one? Burned up wires.

Here is a nice box you could use to run some things.
 

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Discussion Starter #7
Well, the bottom line I'm curious to satisfy is whether the new alternator produces a straight 80 amps, or only enough to satisfy the load. I'm concerned that if I double the rated output of a stock alternator with a new one, that I'll either start an electrical fire or burn out the ECU.

Will an alternator produce only the necessary amperage, or the entire rated output at a time?
 

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Well, the bottom line I'm curious to satisfy is whether the new alternator produces a straight 80 amps, or only enough to satisfy the load. I'm concerned that if I double the rated output of a stock alternator with a new one, that I'll either start an electrical fire or burn out the ECU.

Will an alternator produce only the necessary amperage, or the entire rated output at a time?
I believe that the part in question, actually Alternates, voltage and amp's, based on need.


The problem you have is, using the stock wiring. It will not take you just splicing in anywhere you want. If you want these kind of HEAVY draw accessories, you need a "side" system that can handle it.
 
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