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Alternator help


Original_Ranger84

Well-Known Member
TRS Banner 2012-2015
Joined
Aug 23, 2007
Messages
4,688
City
Homer, Ak/ Anchorage, AK/Fairbanks, AK
Vehicle Year
1984, 1999
Transmission
Manual
Hey, So I'm going to be picking up a new alternator for my truck today and was wondering what I should get.

Its a 99 ranger with the 3.0L, I'm running a new stereo thats about 1000 watts combined, and I have 8 KC off road lights I use quite often in the winter time (about 800w combined), and I plan on adding reverse lights and heated seats. I was thinking a 130 amp alternator would work but now I'm thinking I may need a 150 or something.

Also is there a write up on how to add dual alternators to a ranger?

What battery should I get? I would like something like a Red top Optima but is there any similar batteries you guys like with good warrenties? (Yes I need a battery cause my current one is almost 11 years old now. and I don't trust it to keep cranking in the winter time.

Thanks guys :icon_thumby:
 
I had a used allternater from a 90 somthing t-bird that i made fit in my bronco II that was 130 amp.

I had 6 fog lights on it, two on the bumper and four on the roof. They were bright as hell, but walmart brand so i couldnt say how many watts they pushed. I also had a 1000watt sub system in it aswell.

I was pretty satisfied with that alternator. I load tested it after i put it in by blasting the subs along with every possible electrical load i could turn on running, including the wipers and defroster for the rear window. And the lights were still bright as can be, and the wipers were moving along with not obvious drain on the voltage.


I also had an old cooling from the same t-bird that i wanted to use on the truck, but i could find the right relay for it...and it didnt quite fit under the hood. Well me and a friend for fun hooked it up to the battery with the engine running and completely burned the motor out since it wasnt going to be used. Needless to say that motor draws a ton of amps. And we burned it to the piont where the windings inside the motor were glowing red, the entire time the alternator showed no signs of overloading or stress fatigue and kept the battery charged through the whole motor torture session lol.


Long story short, if you want go ahead and put a 130 or 150 amp in...i can personally atest that the 130amp alt can put out plenty of power. But a 200amp alt or higher or dual amps is certainly overkill. Unless you had like, the bed filled with subs...or a heavy duty winch


Optima batterys are great. I personally would get the marine battery(blue top) or the yellow top which is a kinda hybrid between the red top and blue. Which will give out great cranking amps for winter, but also last long without charging like the deep cycle blue top. The only reason i dont have one is those batterys cost like 160 bucks....and my original motorcraft battery which is still factory issue for my 03 ranger works entirely fine...and it has been stone dead a few times already from leaving the lights on by mistake lol. If you dont want to fork up the cash for the optima id say stick with motorcraft as they seem to live pretty long.
 
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the 130A "large case" alt can be built to 200A, which should be more than enough. I have never been impressed with the optimas, I would stick with a good quality lead acid battery, (unless you plan on mounting the battery upside down). You will be able to find many lead acid batteries with the same (or better) specs for roughly 1/2 the cost and a better warranty, in most cases. For example the common ford battery,(group 65) in an interstate megaron plus puts out 1000 cranking amps and 850CCA, and has an 85 month warranty. If you want to convert watts to amps, to get a ballpark on your needs you can convert it (Watts/Volts=Amps)
 
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Hmmm, yeah i would say try the 130 amp first then move up if need be.

Using the formula your lights alone draw almost 60 amps... (800/13.8=57amps)

So if that is correct, then the lights your running use nearly half of the 130amps rated output.

Wierd though, i wonder how my bronco II ever ran with the stock 45amp alt lol, cuase apparently running anymore then 800watts worth of load would be overloading it. Think of all the stuff the alternator needs to power from factory, let alone add ons. (headlights, ventilation fan, computer/injectors,wipers,fuel pump etc)

I always just assumed optimas are good batterys, i mean they so danm expensive they friggin better be good.
 
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Hmmm, yeah i would say try the 130 amp first then move up if need be.

Using the formula your lights alone draw almost 60 amps... (800/13.8=57amps)

So if that is correct, then the lights your running use nearly half of the 130amps rated output.

Wierd though, i wonder how my bronco II ever ran with the stock 45amp alt lol, cuase apparently running anymore then 800watts worth of load would be overloading it. Think of all the stuff the alternator needs to power from factory, let alone add ons. (headlights, ventilation fan, computer/injectors,wipers,fuel pump etc)

I always just assumed optimas are good batterys, i mean they so danm expensive they friggin better be good.


Yeah i think 130 should be fine, the stereo never has all 1000w going at once and not for very long if it does. And I can run 400w of lights with my 95 amp just fine with everything else on so... Cool
 

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