Alternator Amperage?

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Alternator Amperage?

January 16, 2006, 01:20:14 PM

Hey, I've got an 88 Cougar XR-7, which means it also only has the 60Amp alternator... What is the maximum current draw I can run for my sound system? I plan on hooking up an Infinity REF7541A (111w x4) amp to it and hope to not have any power problems. I plan on using a quality ground loop isolator also. What is the max amount of amps I can draw from the alternator without killing it? I believe it will be drawing about 37A... with this be a safe number? Or will I have to add a second battery in the trunk and parallel it off the other or should I just a buy a new HO alternator? Thanks for any help!

Alternator Amperage?

Reply #1 – January 16, 2006, 02:27:05 PM

I'm tring to remember, headlights I=20A wipers I=15A interior accessories (A/C, Radio, lights) I=10A. 55A everything on at one time. My suggestion would be to purchase a new alternator. A second battery isnt needed.

Alternator Amperage?

Reply #2 – January 16, 2006, 02:32:20 PM

yes, these alternators are painfully weak, expecialy for something thats sopposed to be a luxury car. IMO they should all be changed out even if you dont have a system. you can realy tell its struggling at nite when you stop and your lights all dim

Alternator Amperage?

Reply #3 – January 16, 2006, 02:33:03 PM

The 1986-88 Cougar/T-Bird 5.0 alternator should be 65-amp. You can retrofit a stock 1987-93 Mustang 5.0 alternator if you do a little bit of grinding to the alternator bracket; the harnesses are identical to yours. That is a 75-amp alternator. Or you could just bite the bullet and go with a 1994-95 Mustang 5.0 (3G) 130-amp alternator, which does require rewiring. I believe others have reported using a Taurus 3.0 V6 alternator (3G) as well.

Alternator Amperage?

Reply #4 – January 16, 2006, 04:28:16 PM

Does anyone know of any aftermarket alternators I could use or any good sites to get one that will work without too much rewiring, etc. I'm looking to get atleast 100A. Thanks for the help!

Alternator Amperage?

Reply #5 – January 16, 2006, 04:35:10 PM

http://www.paperformance.com/ is one site I see mentioned now and again here.

Alternator Amperage?

Reply #6 – January 16, 2006, 04:57:54 PM

Thanks for the link! Now I just gotta figure out all the sizes etc. for my Cougar...

Alternator Amperage?

Reply #7 – January 17, 2006, 01:02:10 AM

I've been looking around alot at other people's 88 XR7s on Cardomain and there seems to be quite a few people on there with nice sound systems complete with subs, amps and all running on stock alternators with upgraded batteries. Do any of you think I could get away with the stock alternator, using a deep cycle yellow top battery, and a good capacitor for my subs. Once again, I'm planning on using a single Infinity 4x111w amp. I really don't want to have to dish out another $200+ for a new alternator, another $60 for the new wiring harness/kit for it, etc, just for a pretty much overall nothing crazy, mild sound system. Any advice?

Alternator Amperage?

Reply #8 – January 17, 2006, 08:34:58 AM

a bigger battery is a bandaid on a bleeding artery. Same with the capacitors. Just go to the junk yard and look for a certain kind of battery. You would prolly be fine if you wanna go with the stock alt, but that will make it eat itself faster, then you are paying the $200 anyways.

Alternator Amperage?

Reply #9 – January 17, 2006, 02:59:17 PM

all a capacitor does is make it so when your basshiznitts real hard your car doesnt die. a bigger batter (like was said earlier) is a bandade for a bleading artery. the only way to do it right is to put in a bigger charging system.

Alternator Amperage?

Reply #10 – January 17, 2006, 03:18:33 PM

Yeah, I was afraid of that... Oh well, I guess I'll just go with replacing the stock speakers with Alpine Type-Rs and replace the HU and leave it at that with no subs or extra amps for now... I do have a limited budget of about $600 and with the rest of the speakers I was going to use, the amps, the amp wiring kits, the new alternator, and new alternator wiring kit, etc. it's opened a whole can of worms that is going to cost a good $1200. Anyone interested in buying a brand new pair of Infinity 10" 1040W Subs? I just got them last week and haven't even been used, hell I still had the boxes until yesterday. I'll even throw in a sealed enclosure to match. Anyone interested? I can't use them at all now that I find out that It's gonna cost a lot more to do a nice system in my car. Make me an offer, I'm not looking to profit, just lessen my losses... Thanks!

Alternator Amperage?

Reply #11 – January 17, 2006, 03:32:57 PM

Hold on to them, Just save the cash, you can prolly find the correct alternator in your local junk yard. No need to give up hope yet.

Alternator Amperage?

Reply #12 – January 17, 2006, 04:38:28 PM

Can't speak for everyone here and won't try to, but I can say with my one experience putting in a 95A 3G alt (and a pro-rated replacement of the battery that the old alt killed.. only cost me $7.. Wal-Mart's good for something) that I feel much better about the charging system on that car, and want to do it to the other two driveable vehicles here when I can.. even though the alt in my LSC is supposed to be 100A already. (larger case, and externally regulated) The re-wiring wasn't bad even for someone as rusty (not to mention brain-dead) on this kind of thing as I was/am.. although in all fairness, on that particular vehicle the alt is only about a foot from the battery. :p Eventually I'll put decent stereos in a couple of these vehicles, too.. and it's nice to know I'll have the capacity to handle 'em.

Now if only PA Performance listed something (alt, anyway) that worked on my old Dodge.. :D

Alternator Amperage?

Reply #13 – January 17, 2006, 04:55:20 PM

Cool. I'm just wondering how all 6 of my speakers will work off of the HU amp. I'm planning on getting an Alpine CDE-9846 HU (16x4 RMS)... I want to replace the 6x8 rears, 6.5" doors, and 3.5" dash's with new Alpine Type-Rs. The guy I just spoke to from Crutchfield just told me that all 6 speakers will still work using their Ford wireharness ( Found here: http://www.crutchfield.com/S-DzLtR2eE8CR/cgi-bin/ProdView.asp?g=103000&id=essential_info&i=120705005#Tab

My wiring Diagram from Sam's is here:
http://www.foxthundercats.com/tech/wiringdiagrams/8588basepremiumwoeq.pdf

From that diagram I can tell that my door and dash speakers are run parallel off of the stock amp and the rears have their own channels. I just can't figure out the impedance of the amp. Like, If these door and dash speakers are in parallel and are running at 4ohms, then the amp must be pushing a load of 8 ohms, right? So if my HU amp is pushing at 4 ohms, then paralleling them off the HU with the bybass harness will force the speakers at 2 ohms right? I'm really confused with the best way to wire this set up without burning out my HU amp. Apparently the bypass harness runs all the power from the HU to the rear of the car where I'll cut the speaker leads off of the stock amp and reconnect them to the HU... Ugg.. my head hurts. I'm clear on everything except the resulting impedances of running the doors and dash in parallel. Thanks for all the help thus far, you guys have really been a big help in preventing me making any stupid mistakes. I'll be sure to get some pics of my beautiful cat up once it's done.

Alternator Amperage?

Reply #14 – January 17, 2006, 07:22:58 PM

the power will follow the path of least resistance. so if you have speakers wired in paralell on at say 4 ohms and the other at 2 ohms then there will be a 2 ohm resistance in that circuit.