Alternator - Dodge Dakota Forum

Subject: Alternator
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I was looking to buy a new Alternator, and I noticed that the local Autozone had them in stock. It seems that you can trade in your old one and get a considerable discount, because the will reuse it. Has anyone done this? And are they good?

Also, i would like to know how many amps a 800 RMS amplifier requires?

Any help would be great.

Jim Z
GenI

6/06/2004
21:06:53

RE: Alternator
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It seems that you can trade in your old one and get a considerable discount, because the will reuse it. Has anyone done this?

This is fairly standard for a lot of automotive parts. It isn't that you're getting a discount, though. Remnaufactured parts typically have a "core deposit charge" tacked on to ensure that you bring your old part back so it can be rebuilt and sold. Say, for example, you go to buy a starter. The list price is $199 + $50 core deposit. What this means is that when you buy the starter, you pay $249, and you get the $50 back when you give them your old starter.

casedeez
Dodge Dakota
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6/07/2004
03:43:17

RE: Alternator
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If your amp is truly creating 800 watts you would be drawing 128 amps.

midnightdak
Dodge Dakota
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6/07/2004
11:54:16

RE: Alternator
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casedeez

i have a 1500watt amp and i still have my stock alternator,i never really understood why people upgraded theres i mean i know what for but i just dont see the real point for spending the money.I dont even have a cap now,but im getting 1 today cause my lights flash like cops lights...lol.And jims right you pay 249 and whenever you take your core back you get your 50 back

casedeez
Dodge Dakota
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6/07/2004
14:17:56

RE: Alternator
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Well you can run your stock alternator. Personally I dont care, and if you dont then your set. You might want to think about what your depriving your amp of though. Oh, and the rest of your electrical system would like a better alternator too. Just so you know a cap wont help you if your alternator is too small. If your elec sys is weak, then you need a new alternator, its that simple.

Lurkin
Dodge Dakota
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6/07/2004
16:10:33

RE: Alternator
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casedeez, is your math right above?

800W / 12V = 66.7amps

Are you accounting for peak power, or have I missed something...

casedeez
Dodge Dakota
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6/07/2004
17:05:54

RE: Alternator
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I was going off a quick referance guide which assumes that 800 watts is the rms power and the amplifier has a 50% efficiency rating. http://www.the12volt.com/info/recwirsz.asp

So here it is summed up.
1st -- We cant fully know what kind of draw he will be taking form the alternator merely because we dont know what amp he has. But lets pretend his amp is rated at 800 watts RMS at full output... with a power effeciancy rating of say 60% effeciancy. This seems pretty standard.
Now generally speaking most vehicles elec sys run at about 13 VDC. My dakota is more lik 12.8 12.9. In any case 13VDC is our given voltage. So...
800/0.6 = 1333 (rounded down)this is input power to amp.
Power eqaution is P=V x I where P=power V = input voltage and finally I = input current known to most as amps.
rearrange it to look like this --->>> I=P/V and violla (i think thats how its spelled)
Ok so for the final part we plug in the numbers much like you did except with a slight more accurate twist and we get 1333/13 = 102.5 amps.
This is a more accurate rating for that particular amp in the given situation.

Instead of doing all this, what you could do is invest in the baddest as s biggest most powerful alt you can find and call it good. In this case, make sure it fits before you buy it.

Alec
Dodge Dakota
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6/09/2004
18:16:12

RE: Alternator
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Thanks so much for the Input!!!!!!

I have the crappy 80 watt alternator, so im gonna see how bad it is before i get a new one (this is gonna be funny!)

Any further input is greatly appreciated too.

DSW
Dodge Dakota
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6/10/2004
18:03:43

RE: Alternator
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If you get an alternator at Autozone they will want the same exact type of core for the part that they sold you, they won't take an 80amp alternator core for a 130amp alternator. Well, at least they are not supposed to....

Don't take in your 80 amp alt when you buy the new 130 amp alt. If you set your old one next to the new one they will see the difference in the alternators. If you bring the 80 amp alt back in after a couple of days they might accept it and refund the core charge.

Alec
Dodge Dakota
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6/10/2004
23:44:56

RE: Alternator
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HAHAHA, sweet thinking!

Im jsut worrying about the quality of the AutoZone Alternator.....

93KotaOwner
Dodge Dakota
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6/11/2004
07:10:41

RE: Alternator
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I have two amps totallying 800 watts, does anybody know if I should invest in a better alternator? IF so how much could I expect to pay?

LAD9DER
Dodge Dakota
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6/12/2004
01:12:09

RE: Alternator
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If your lights dim or flash at all you need a bigger alternator. If you want to really run big then you will probably need a better battery or even a second battery. A capacitor is nothing more than a small battery, it stores power until it is needed, the current is flowing through the cap at all times, the cap just provides a little extra "oomph" when you need it. My Dak came with the bigger alternator, I run 1 full farad cap right before the amp which is a PPI PC650 bridged to 3 channels, Left Front, Right front and Sub. It hits LOUD and clean and I get absolutely no dimming or flashing at all. A cheap amp that says "800" watts is probably rated at it's maximum output, which is nowhere near the actual RMS value of the amp. I let my Eclipse head unit handle the rolled off rear speakers just for a little fill, Mb Quart comp's up front off of the amp. Not saying you are running cheap stuff - just my 2 cents worth.

trueno
Dodge Dakota
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11/13/2009
19:59:27