Ok heres the deal. I already have a 220 watt amp and I'm thinking about adding some driving/fog lights. I have the 97 amp alternator on my car right now. It's only about 8 months old as I blew the original one last year. I had had the amp for about 6 months and figured it blew b/c it was a 120k mile alternator. Any help would be a apprieciated here. I would prefer not to be stranded on the side of the road this time just b/c I had to have driving lights.

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Red 1986 SC, 2.8L, rebuilt 700R4, 3.42 Posi, t-tops, 134K miles and counting, K&N air filters, hopefully more to come!

 

I run 3 MTX 280's, an electronic cross overm, Fog lights, and an MSD. I bought a 104 amp(I think) from a late model GM Full size truck. The casing is a little bigger, but you get more amperage and it will last longer. I have had no problems with this set up except that I had to put a rubber gromet between a metal tube and the alternator connection because it was making a spark when you bumped it.

 

If you plan to get pullys get a 140 amp from summit i had chargind problems evey time bass would hit my lights would blink to the bass. the alternator is about 300 or so

 

pulleys are junk.. every car i seen em on had charging and cooling problems for about a half hp of a gain.. depends on the alternator, personally ive been thru 4 "hi output" autozone alternators.. and thats only with two amps, a mtx 502 for the componets and a 3002 for the subs, even with a cap i still get a little light dimage at nite when i got the lights on and drawing power too.. all depends on the alternator.. personally i'll never buy another from autozone again..

 

Thanks for all the imput guys! So it should be fine w/ the 220W amp and the fog lights? The fog lights I looked at were only 35W anyway. BTW I don't plan on getting any pulleys. I've also heard that they cause too much drainage as well. One more ?, the number is how much the alternator can handle right? Ex. my 97 amp can handle 97 amps. Am I right on that? I figured up a while back after my first one died that my 220 watt amp is something like 17 amps. Is that right? If so how many amps are things like bright lights, dim lights, A/C and etc? I hardly ever run the AC but when I have my gf in the car on a hot summer day I don't really have a choice.

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Red 1986 SC, 2.8L, rebuilt 700R4, 3.42 Posi, t-tops, 134K miles and counting, K&N air filters, hopefully more to come!

 

Power = current * voltage

So 17A*13V = 221 Watts...

but amp manufacturers like to lie about the wattage of their amps. You won't be using the full about of power through the amp all of the time. If you can, try measuring the current while playing a song with lots of bass. I'd suggest songs but that's likely to start a flame war .

The fog lights probably are actually 35W since they're going 100% when you have them turned on.

Your battery will provide reserve power if you draw too much from the alternator, so make sure you have a good battery.

Another thing you might want to do to avoid strain on the alternator is put a big-*** capacitor inline with the amp (right near where the +12V goes into the amp). This will give it some extra reserve for the big bass.

Alex

 

Alex is right; if your amp doesn't specify between "RMS" power and "Peak" power, then it's probably listing just the "peak".

RMS is calculated, and every amp manufacturer uses the same calculation.

There's no standard for peak.

Sometimes it's good to go by the fuses on the amps! I have a Mobile Authority "Thump" amp right now, since I melted my Rockford Fosgate. The Rockford was a 60x2 RMS watt amp, and had a 30 amp fuse. The Thump "claims" to be 220x2 watt, but it has a 15 amp fuse!

Anyway, the Thump will max draw 15 amps. The Rockford's draw on the alternator was 30 amps max.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

just like tom said.. add up the ratings on all the fuses of stuff thats on, and that will give you a general (slightly high) ballpark figure of drain.. or you could install a ammeter inline with your alternator and know exactally how many amps everything is drawing...

 

That really helped me out a lot, thanks for the help!!

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Red 1986 SC, 2.8L, rebuilt 700R4, 3.42 Posi, t-tops, 134K miles and counting, K&N air filters, hopefully more to come!

 

I think pullys made a big difference for me not only powerwise but also increased my gas milage by 50 miles per tank