Question asked by Fred85:

I am a true fan of drive-in theatres! The season has just begun but I had a problem with my car and some people think it might be the battery. I installed a sound system of 2000w with a subwoofer in my car (Sentra 2005) and my car did not start after the second film. I had to boost it! I don’t understand because I started my engine for 15 minutes between the two films. Help!

Answer:

Hello Fred85,

In general, a powerful sound system demands more amps which can drain a car battery for long periods of time (two drive-in movies, for example). Automotive batteries are designed to give a lot of power in a short time period (starting) combine with a small amount of reserve of amps. This reserve is designed to provide power to the lights and the vehicle’s radio for a limited period of time. The battery gives a lot of its power to start the engine and the alternator recharge it when the car is rolling on the road. This is the reason why vehicles with a big sound system, add an independent 12V deep cycle battery in the trunk. This battery will supply the sound system without using the energy of the starting batteries.

In Your Case:

Since we do not know the exact amps demand of your sound system, we believe that your problem could be caused by one of the three following reasons:

The age of the Battery.

The older you’re car batteries gets, the less power it will give. Usually, the life of a battery is about 5 years. Maybe yours is on the verge of rendering its soul.

Starting the car’s engine between the two films.

Your idea was a good one but starting your vehicle between two films may have given the final blow to your battery. During start up, much amperage is needed. When your car was idling for 15 minutes, your alternator probably didn’t even recharge the energy needed to start the car. You didn’t even scratch the surface of the energy consumed by your sound system. In such cases, it would be better, simply, not to start the engine between two movies.

A Powerful Sound System.

As mentioned above, maybe your sound system is simply too demanding compared to what your car battery can provide. Perhaps you should consider adding a deep cycle battery in the trunk of the car.

Action or Romantic Movie?

Take note that the sound system’s energy consumption varies when it is more solicited. A movie with crazy loud action will consume more energy than a romantic comedy...

In conclusion

NWe advise you to go to a Batteries Expert store with the instruction booklet of your sound system. Our experts will tell you if your car’s battery is too old or if you need an additional 12V deep cycle battery in order to connect your sound system.

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