140 amp high output alternator

[sketchman]

Using extras batteries/caps doesn't help?

[bhearts]

supa caps! you can series up a couple 3300F caps, to get 18v at 400F or so. itd cost you around 300$. but itd be worth it in my mind.

[william]

Extra battery's or much larger ones is the way to go.
I like deep cycle marine there cheap and cut the volt drop.
I had a 1500 rock Ford amp and 2 p3's and it would make the headlights all most go out at a idle and that's a small setup to most audio guys. I put in a nice big battery and problem solved as stated before I would pop the fuse with the stock alt. With my stock size battery because it would pull so much that when it went to charge it wood push so much threw the stock fuse it would blow.

[mikeyjd]

A stock alternator uses roughly 10% of your hp to the wheel demand at speed. Roughly 4-5mpg with a stock alternator. Just thought I'd mention it since you want to make it 8-10mpg

[Basement_Modder]

That is true, I don't want to lose too much mileage... I suppose I'll just go with a MPV 70 amp stocker and an optima yellow top. I'll use a cap if needed but I don't want to as its mostly a band-aid at best.

Edit- its worth noting that eventually I want to run 2 sundown SA 12s with a Rockford T1500-1bdcp.

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[zoom zoom]

Are you trying to say a stock alternator eats up your miles per gallon?



/e I'm not stupid I just want to reaffirm you are.. or aren't if you say no.

[bhearts]

At a full 70 amps of current draw, you could expect your alternator to be eating up no more than 2hp. Power is equal to current times volts, so 70x14 which is about 1000watts. 1hp is rated at 700 some watts, let's say 750. You're alternator is at least 60 percent efficiency, so 1.25hp multiplied by 10/6, which shows how much power it'd take to create that much current with a set efficiency rating. Roughly 2hp

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[bhearts]

That's at full current, the festiva stock alt is 40amps, right? And I bet alternators are set about 33 percent above full current draw on a system. So you could expect the cars requirement of current at a max to be around 30 amps. Which would require 1hp at the highest draw. Let me know if that stock alternator rating isn't right.

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[Pu241]

Are you trying to say a stock alternator eats up your miles per gallon?
/e I'm not stupid I just want to reaffirm you are.. or aren't if you say no.

It is known through ABA testing (make a tank run with the ATL, remove ALT and run a tank without, put ALT back on for final run) that the ALTs in many different cars exacts a 10% penalty in MPG.
Ecomodder.com has documented this numerous times.

[Team Lightning]

I just got my alternator back from the shop and it was tested at 55 amps on his tester.

[bhearts]

10 percent sounds about right. Isn't it like 12hp to hold a festiva at 55mph. Add a parasitic 1hp onto that, and that's around 10 percent extra fuel

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[zoom zoom]

You guys are getting way too technical. Ive used alternators ranging from stock festy to protege and rio's, and have never noticed any difference in mpgs with any of them. If what your saying is true then i should be getting worse gas milage in my aspire with a 1000w amp that is always on making the speakers hit so hard it shakes the mirrors. I don't have dimming light issues after putting in a bigger battery, and my gas milage isn't any worse for it. Any mpg loss is negligible at best.

[mikeyjd]

You guys are getting way too technical. Ive used alternators ranging from stock festy to protege and rio's, and have never noticed any difference in mpgs with any of them. If what your saying is true then i should be getting worse gas milage in my aspire with a 1000w amp that is always on making the speakers hit so hard it shakes the mirrors. I don't have dimming light issues after putting in a bigger battery, and my gas milage isn't any worse for it. Any mpg loss is negligible at best.

Have you ever tested a tank without your alternator? 10% is hardly negligible. That is probably about 4 mpg for most people.

[Pu241]

You guys are getting way too technical. Ive used alternators ranging from stock festy to protege and rio's, and have never noticed any difference in mpgs with any of them. If what your saying is true then i should be getting worse gas milage in my aspire with a 1000w amp that is always on making the speakers hit so hard it shakes the mirrors. I don't have dimming light issues after putting in a bigger battery, and my gas milage isn't any worse for it. Any mpg loss is negligible at best.

Yes, its a little technical, but isn't rebuilding/swapping an engine technical?
Isn't that what most of us try to do here, provide facts.
Well, except for an individual from OZ.
How closely do you monitor your MPG?
The 3-4 MPG is with deleting the ALT altogether.
The MPG loss from loading the ALT is going to be less.
How much less would only be a guess.
The max loss would be if you had your ALT at max load continuously, like you said when you didn't have the bigger battery, you experienced dimmed head light, from the voltage drop.
Do you have any MPG data before and after you installed the larger battery?
That might tell you/us something provided they are tanks burned under similar conditions.

[Rocketman]

You guys are missing the point. It's not generating 140amps all the time, it's supplying ONLY to the electrical demand. 140amps is the limit to which it can supply.

If the stock electrical system pulls 30 amps during driving, the stock 70amp alt will supply 30 amps, as will the upgraded 140amp alt. So you're not going to notice a difference in economy there.

If you pull a heavy load, such as a stereo system or a sybian machine, you're gonna pull more amps & that's going to require more power, which may impact overall economy.

This is all besides parasitic losses from having to turn a 'thing', efficiencies, etc...but this is the bottom line.