there could be something draining the battery like parking lights or the glove box...

 

About 40k I believe.

I made sure they were off.

My dad is going to bring home a multimeter to test the battery from work today, I think it might be my battery, because a few nights before, I was up Metcalf Road , with the stereo on (I have 1000 and 1200 watt amps running) but the car was off. so my best guess is running those without a capacitor killed the battery?

 

Si Senor.

 

just curious, how can draining the battery actually kill it?

im not to good with electricity

 

I really need to buy a cap lol

 

Batteries don't last forever, eventually they gonna die if you drain the power out of them for long enough it just shortens the lifespan I think? lol

 

Most lead-acid batteries don't like to be fully discharged - it damages the plates and reduces the life expectancy of the battery.

 

so why when you buy a cellphone does it tell you to let the battery fully drain then recharge it the first couple of times?

 

Those are made out of different materials?

 

Li-Ion batteries are different than car batteries which rely on acid to conduct electricity.

 

I got one for sale if my neighbor flakes out. small one. 1.2 farad. tsunami. let m eknow

 

How much?

 

well that advice stems from PRE-computered cars.

these days, you may have a car with more than 1 ECU and they are more thingeed with voltage spikes and stuff...

 

hold on.

a capacitor IS NOT a battery. it's a temporary storage device.

with or without a capacitor, without the engine running, the whole stereo is running off the battery.

what kills the battery is constant cycling of the battery from fully charged to <10 volts.

 

If its a subaru stock battery they are pretty much crap anyway, 40,000 mi /8 years is a really long life for one of them....