Christopher Albers wrote:
> I have an intermittent charging problem.
>
> For reasons unknown my alternator only puts out about 10V at times and
> then at others puts out close to 14V. During normal operation my amp
> gauge reads nearly 35 amps of output most of the time. Lately the
> needle has been showing a discharge condition (10V) and will sometimes
> mysteriously return to 35 amps without warning. I have a 50amp fuse
> running between the alternator and it's direct connection to the meter.
> In the past, jiggling the fuse returned the meter to charge, but it's
> no longer working. My voltage regulator appears to be functioning
> normally.
>
> I have recently added a 10" woofer to my stereo system and the
> electrical system cannot handle it. The amp meter buries itself at
> discharge if I ever turn on the stereo with the woofer hooked up (it
> still charges with just 4 speakers in use). I have been told that I
> need a component called a "stiffening cap," which is basically a 1
> farad capacitor. It's supposed to take the load off the alternator. I
> have not been running the stereo since the charging problem appeared.
>
> Two questions: Where do I look to fix my charging problem? Will a
> stiffening cap solve my power needs?
>
> Jarrid, I have a feeling this is down your alley.
>
> Christopher
Chris,
A 1 farad cap will make a pretty good filter for the alternator ripple,
and will hold the charge voltage up, during hard power transients like
a good base thump. It will not however unload the alternator, but rather
spread the spike load across a longer period of time, with a smaller
effective instaneous load.
If the current need is continuous, the cap wont really help, save to
make your sound system have less alternator hum.
If just connecting the woofer, at low sound levels cuases a substancial
power draw, consider that perhaps the amp is defective, or improperly
wired. Is the woofers amp a bridge amp by any chance? If so,
you must never use the chassis as a return for the speaker wires,
as was typical for stereos in older cars.
The alternato should not read 35 amps continously, but should only
do so for a brief period after starting, and then it should decay down
toward 0 amperes.
Fuses can and often do appear good, when the ends
of the metal links (not visible) have melted, or offer only intermitent
contact.
If you dont have one, install a fusable link in series with the alternator
instead of a fuse. It will be far less likely to blow with short, but high
peak currents.
Hope this helps,
Jarrid
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