Christopher wrote,
>There really isn't any alternator hum. There's just an incredible
>amount of load whenever I turn on the stereo. Even without the
>subwoofer the alternator slips into discharge at idle.
But there really shouldnt be a huge load just by turning on the stereo.
There are different classes of amplifiers used in audio equip.
Automotive usually uses a bridged class AB power stage on the outputs.
These amps are fairly efficient in thier use of power, and consume
relatively low amounts of current in no/low volume situations.
Thes amps can put a voltage of 28v peak to peak into a 8,4 or
2 ohm load, which is the only way you can make the 100+ watts that
the mfgrs claim on the amps.
Other types of amps are cleaner, but less efficient in thier use
of power. These amps (IE class A) typically cannot be bridged and
thus can only put out about 11v peak to peak, and 2/3 of the energy
used doesnt make it into the speakers.
I doubt that a high end auto sound system would use this, but a very
high end home system might.
>I believe it's hooked up correctly. Since my stereo only has two
>preamp outputs (front & rear) the sub runs off a mono sum from the reap
>output.
So is the woofer connected to the rear right+, and the rear left-, or
something like that?
>I messed with the adjustment pot on the back of the voltage reg last
>night and the output now is in the charge range, though too much, as
>before. Unless a substantial load is placed on the electrical system,
>the amp meter pegs at 35 amps anywhere above 2500 rpm (eng speed).
>However, at idle the needle drops to 35 amps of discharge.
This says that your current requirement it greater than 35 amps.
I would'nt go messing with adjustments unless you know whats wrong, and
specifically what you are adjusting.
The pot in the regulator could a a voltage adjustment, or it could be
a current limit adjustment. Could also be a loop gain adjustment
so the same regulator can be used on different capacity alternators
and still be stable.
With the stereo off, will the ammeter eventually run to a charge
current of less than 5amps?
If not,
A) The voltage regulator is puting out too much voltage.
or
B) The battery has an internal cell shorted.
or
C) There is something amiss with one or more of your electrics (IE Stereo)
Get the specs on you stereo gear.
There should be something there on the quiescent current of the amp/stereo.
This should match what you can measure in the car.
If not, you at least know what component is stealing your juice.
Also...
Its a good idea you built that engine for more power because your high
output
stereo will consume approx .2 BHP per ampere alternator output.
Jarrid
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