On Tue, 2 Dec 2003 18:31:06 -0800, "SHRED©" wrote:

I am on my 4th alternator in my 1991 Integra.
Napa autocare service centers are replacing them, under warranty, until now.
They referred me to an auto-electric shop. This shop claims that my car's
wiring is fine but the amplifier in my car is responsible for destroying the
Napa alternators.

I have an Alpine MRD-F752 5ch (75wx4 and 250wx1) driving 4 PA DX6's and a JL
Audio 12".

The mechanic at the auto-elec shop claims that he tested the amp and it is
drawing between 50-80 amps!! This is a 60amp rated alternator so with the
lights and A/C, etc..he claims the stereo is pushing it over the edge.

Wait a minute...Watts divided by volts= amps.
325w / 12v = 27amps..right?

Why are you using 325 watts? 75*4 + 250*1 is 550 watts. I know you
probably don't crank it that loud very often, but don't forget that
amplifiers are not 100% efficient. You could easily pull 50 amps with
this amplifier without turning it all the way up.

Why would that Alpine be reading so high?

Why do my headlight dim with the bass note thumps even when not blasting?

This is a sure sign that your amp is drawing more current than the
alternator can supply. Your electrical system has to dip into the
battery to try to supply the additional current for the bass notes,
and the current drain through the battery's internal resistance is
causing a voltage drop. That is what's causing your lights to dim.

I think it is a Napa alternator issue...as in junk.

It may be a perfectly functioning alternator, but a 60-amp model just
isn't adequate for your needs. If you constantly ask it to provide a
current that is near its limits, it will shorten the lifespan
dramatically.

I have to call them in the morning and let them know if I am going to remove
the amplifier. Damn I'd hate to do that it sounds so sweet.

WTF can I do? I am scrambling for electrical answers I know little of.

Why do my friends, in little Honda Civics and other vehicles, have no
problems driving 500 watts with the stock alternators?

I don't know how big the alternator is in a stock Civic, and 500 watts
is actually smaller than your amp, not larger.


Scott Gardner

Thanks