Honda Car Forum

Without running engine, I played about hour of 600watt amp in my car.
Then I could not
start the car. The battery got weaken. so I recharged the battery for
15 min. It got start.
Could playing 600watt amplifier of car stereo in hour dried the
battery down? Or my battery is a weak battery.

<mmdir2005@yahoo.com> wrote in message
news:1158829108.387281.90490@d34g2000cwd.googlegro ups.com...
>
> Without running engine, I played about hour of 600watt amp in my car.
> Then I could not
> start the car. The battery got weaken. so I recharged the battery for
> 15 min. It got start.
> Could playing 600watt amplifier of car stereo in hour dried the
> battery down? Or my battery is a weak battery.

It's entirely because you were playing the stereo with the car not running.

If you need to do that, then install a 2nd battery (a deep cycle), wire the
stereo gear to run off that battery and hook that battery to the first with
a dual battery isolator. This way when the car is running it is charging
both batteries, but when the car is off the "stereo battery" is not charging
itself from the "main battery" while it gets used to power the stereo.

mmdir2005@yahoo.com wrote:
> Without running engine, I played about hour of 600watt amp in my car.
> Then I could not
> start the car. The battery got weaken. so I recharged the battery for
> 15 min. It got start.
> Could playing 600watt amplifier of car stereo in hour dried the
> battery down? Or my battery is a weak battery.

Well... heck, whatdaya expect.. 600w .. That a lot of power if it's
truly 600 watts output. But then you have to consider that the rating
may be for *output*. The input power rating will likely be double or
more
that. It's a class A amp.. So lets just say the input power rating
is 1200w to get 600w out. You are running the amp off the battery
with the engine off. So lets says the voltage is 12.8 volts as an
average number. It will actually drop as the battery runs down.
On peaks, that amp is drawing nearly 94 amps of current.
Look a the amp hour rating of your battery.. It's probably not a
heck of a lot more than 100 amps. So your battery life is fairly
normal. You are going to ruin that battery if you keep doing that.
Every heavy discharge lowers the capacity a bit. If the battery is
old, it's not going to be as good either. Like the other guy said,
you need to run multi batteries, and a deep cycle handles discharges
better than a regular car battery. But even a deep cycle will last
longer if you don't discharge it a lot. I have one I run one of my
radios
on. I use it here in the house, and also out camping, etc..
I often run the radios, and also a TV, VCR/DVD player off a converter
when camping. I keep an eye on my voltage, and charge the batteries
when needed. I generally don't use the car starter battery to power
my toys. I don't like getting stuck. I think my current deep cycle is

a 105 amp hour, but I'd have to get up and look to make sure..
I keep an automatic charger on it 24/7. It never runs down normally.
MK

mmdir2005@yahoo.com wrote:
> Without running engine, I played about hour of 600watt amp in my car.

At full volume ? Do you still hear anything ?

> Then I could not start the car.

600 watts / 12 volt = 50 A. So in an hour it would spend about 50Ah. *

If your car has a gasoline engine, its battery has probably a rating of
about 40 Ah. So it is not surprising that it discharged.


* except that the amplifier probably did not use 600 watts. At full
volume it would use more than that, since it is not 100% efficient.
At lower volumes it would use less. But it should be in the ballpark.

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