High-output alternator source

[Lokim]

I was poking around since I'm going to be upgrading my stereo soon and found this:

http://www.qualitypowerauto.com/catalog.php?item=205

No core charge, 1-year warranty, free shipping, nearly double the factory output and only $87 more than a reman from Joe.

Now, before you all start talking about OEM reliability and all, just remember that a powerful audio system will kill the alternator in a big hurry.
It is likely the higher-output unit with a little extra headroom will last longer under the additional load than a factory unit straining to keep up.

Just in case anybody was looking for one...

[qship96]

I like that 200 amp alternator for the G50 !!!! Only thing I would want to see before jumping on it is the amp output curve.......200 amps at what RPM? and more telling and important, what is amp output at idle, and 2000 rpm {60 mph daily driving}. Sometimes these high output alternators produce great peak numbers at high RPM, but less than the factory alternator at idle and lower rpm.....very important to find out before purchasing!!!!!

200 amps would do wonders for high output audio, or in my case lighting .

[Lokim]

Yeah, I sent them an email requesting those specs. I'll pass on the info once they respond.

They also will rebuild your alternator with the power upgrade, so I asked what that would cost as well since I have a JY alt. laying around.
I'll pass that info along as well.

[Lokim]

Got a response from Quality Power, here's the email reply they sent me:

"If you would like to ship us your alternator we can upgrade it to 200 amp (including bearings, brushes, etc) for $195.00. You would be responsible for shipping it to us and we would include regular ground shipping back to you in the continental US. Our 200 amp alternator will provide about 110 amp at idle and should reach max output by 1600 - 1800 engine RPM. These numbers are from our testing at a 750 RPM idle with a 3:1 pulley ratio. You numbers could be slightly different depending on your idle speed and pulley ratio. We have no problems with the cooling at that amperage.

Quality Power
31510 Yucaipa Blvd.
Yucaipa, CA 92399
(909) 794-1600"

Sounds too good to be true, huh qship? Now to see which of us will be the guinea pig...

[Infinitiguy19]

That sounds nice but how much life can we expect from it? But like you say there is no way to know other than testing it.

[Lokim]

That sounds nice but how much life can we expect from it? But like you say there is no way to know other than testing it.

Conversely, how much life can you expect from a factory unit being asked to produce full amperage full time...

[qship96]

sounds interesting! I have been doing a little research by doing internet searches on the topic {and fully want to disclose I am NO expert on the topic nor know what I have read is accurate or not} here is a little of information I have read

1. more than one article I stumbled across says that to effectively increase amp output,you need a physically larger alternator than your stock size one if longevity is important {I gather this is to handle the extra heat load}

2. you must upgrade to a thicker wire or piggyback {fused} a second power wire from alt to battery to handle the extra amperage to safely utilize the extra power

again,I am no expert on the topic,but the above seems to make sense to me,especially if you will demand the new alternator to produce near its max power for an extended period of time.....not sure how likely that is,as I think most of us are more interested in obtaining the extra amperage at idle speeds, not the full 200 amp output on a continuous basis?

If my original alternator ever dies, I think I would be willing to give it a try!

[Lokim]

I certainly agree with the larger wire to handle the current from the alternator to the battery, but I'm not convinced the size/cooling is as big an issue as you might think.

I know from basic electrical theory that electricity generation is related directly to the strength of the magnetic field present in the generator. This can be adjusted by changing the winding ratios and field coil intensity.

As for cooling, with as tough as the OEM units are (lasting to 100K+) in their original case (which is actually quite large, Sentra alternators are tiny) I don't think heat will be that big an issue. I'd be thrilled if I got more than 50K out of it.

[qship96]

yeah, the oem alternator is one tough unit- I am still on the original at 282K......If we double the output, and cut life by a half, or even 2/3, we are still looking at a reasonable lifespan tradeoff for all the extra juice! Are you going to order one?

[Rex]

I'd be concerned about the unit overheating as well. Audi has some OEM 200 amp alternators, but I think they're all water cooled.

[Lokim]

Probably not for a few months, I need to do struts first.

[maxnix]

If you don't need the extra amperage, you are just decreasing performance with parasitic drag on the engine.

[qship96]

If you don't need the extra amperage, you are just decreasing performance with parasitic drag on the engine.

Not so much,as the "parasitic drag" is proportional to the amperage draw, not potential.... for example, say you are drawing 50 amps at idle using your big stereo and other accessories, the drag, or horsepower usage by the alternator to produce that power is the same whether you have a 110 amp alternator, or a 200 amp alternator.......now sure, if you actually need to produce more amps than the stock alt. produces at a given rpm,the extra amperage provided by a more powerful alternator will create a larger load on engine to produce this amperage, while the stock setup would be draining the battery.

[djwarner]

One horsepower is 746 watts. Assuming 75% efficiency of the alternator, 50 amps at 14 volts would require about 933 watts of power at the pulley. This equates to 1.25 horsepower.

[Infinitiguy19]

All I know is the more load the engine is under at cruise with the AC on in 4th gear while going up hill the worse off you are. But if I am understanding what you are saying correctly the alternator would only require 5 horsepower from the engine MAX?

[maxnix]

i recall (perhaps incorrectly) that at full load the stock alternator required about 13 HP. The mass is greater for a larger capacity, so acceleration times are also affected.

[Rex]

AC & power steering aren't necessary, so just remove those and the higher "load" of a high output alternator would be mitigated

[djwarner]

i recall (perhaps incorrectly) that at full load the stock alternator required about 13 HP. The mass is greater for a larger capacity, so acceleration times are also affected.

The difference between "power out" and "power in" is inefficiency. If I remember correctly, the stock alternator can output something like 130 amps (about 2.44 hp at 14 volts).

If the alternator consumed 13 hp at the pulley, it would be only 19% efficient. The non-electric energy consumed would be turned into heat - equivalent to a 7.8KW heater. A 220 volt electric heater at this power would need at least a 35 amp circuit breaker!

[qship96]

Who gives a crap whether it takes 5 or even 10 HP if it provides the power to drive the electronics you want to enjoy? These old cars are not race cars, and are nowhere near being considered "fast" or "powerful" compared to their contemporaries.

If horsepower and speed is more of a priority over comfort, there are much, much better choices out there than a q45.