Alternators with high amp ratings

syncview

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..than the stock ones.. for example, my car has a 40 amp alternator, I want to go for a bigger alternator for like 80 or 100 amps, I was told by some spare parts guy that putting in a bigger alternator would increase the 'load' on my engine, is that so? :s my engine puts out about 35 HP and 60Nm torque :p
 

Spectre

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Um... not exactly.

If your car draws 20 amps, replacing the 40 amp alternator with a 120 amp one will make no significant difference in how much horsepower is used to generate electricity via the alternator. In fact, you might even have a slight reduction in horsepower loss as more powerful alternators tend to be more efficient, either through more windings, lower rotating mass, or a more powerful rotor.

However, if you replace the 40 amp with a 120 amp unit and then install something that increases your car's draw to 80 amps, yes, you will use more horsepower to generate electricity.
 

the Interceptor

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^ basically, that's it. But since you plan to put in a bigger alternator, I suspect you're going to use it, and that would put more stress on your engine.
 

syncview

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so if I get a 60-80 amp alternator, it should be fine.. what is the relation of the alternator's amps with the corrosions at the terminals or joints, if there is any?

And one more thing, I've found out that my car doesn't have a relay to operate the starter motor, and then it found out it doesn't come with one, should I install one or is it fine this way? or could this be reason my 'ignition switch' has been changed once because the stock one was burned?

btw, the reason I'm going for a bigger alternator is that I'm going to install two additional fans, on the new wide condenser I'm getting for my car..
 
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C53A_4G63T

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Make sure you upgrade the wiring to handle the new alternator. 0ga is usually the best to go with. Car audio or welding cable. The welding cable will actually be cheaper and better.
 

Spectre

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so if I get a 60-80 amp alternator, it should be fine.. what is the relation of the alternator's amps with the corrosions at the terminals or joints, if there is any?

And one more thing, I've found out that my car doesn't have a relay to operate the starter motor, and then it found out it doesn't come with one, should I install one or is it fine this way? or could this be reason my 'ignition switch' has been changed once because the stock one was burned?

btw, the reason I'm going for a bigger alternator is that I'm going to install two additional fans, on the new wide condenser I'm getting for my car..

I'll have to upgrade ALL of the wiring? :eek:

and umm.. can anyone answer my questions in my 2nd post in this thread..


1. Doesn't seem to be any. I went from a 74A to a 320A alternator in the Series III and the connections don't seem to want to corrode any more or less than before. I recently switched to plated terminals and stainless fasteners, so that pretty much ended the whole corrosion angle.

2. I would check your wiring diagram again, I didn't think any car made in the last 30 years shipped without a starter relay of some kind. I mean, even the Yugo had one, IIRC. If you don't have one, by all means add one (of 50A or better rating); even the crappy Ford starter solenoid/relay things are better than nothing.

3. I would make sure you have a fan controller on your fans, if your car doesn't come with one already.

4. You need to upgrade the wiring from the alternator to the battery, and the battery to ground. Trying to pass higher amperage than stock will probably melt your factory cables. Upgrading your starter power cable is also probably a good idea.
 

syncview

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Thanks Spectre..

about #2, I will check that again.. when I got to know about this, I asked the electrician at the dealership, he was like 'No, there isn't one, the starter is operated directly by ignition switch' :s I will check the wiring diagram myself again...

about #3, what is a fan controller, as in the one which switches on the fan when the engine temperature increases, if yes, then my car has one..

about #4, no other wiring would need an upgrade? and it should be good to go?
 
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Spectre

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Nope, though whether you upgrade your alternator or not, the larger/more powerful fans you fit will probably need a wiring upgrade as well - and your stock fan controller may not be able to handle the current.
 
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