Do I need another battery for my car if I have speakers for my car?

you probably will need to get a alternator that puts out more amperage to keep the battery at full charged

I would first suggest that you get an aftermarket HIGH OUTPUT alternator to supply enough voltage for your system and car accessories. An extra battery would help but, mostly if you are stopped and just listening to the radio. If you get an extra battery I would suggest you get a battery isolator. It distributes the voltage to both batteries and when your stopped, just listening to the radio the isolator saves amperage to the main battery so you can start your vehicle.

yes you need a extra heavy duty battery to provde the extra power needed without interfering with the other functions in your car

For the price, you are much better off with a better alternator, an alternator that can supply enough power is much more effective than a weak alternator and a large battery. **Having a larger cup doesn't make the water flow from the faucet any faster or stronger.

why dont u get a capacitor? 1.5 farad will be enough its an alternator and u dona have to do a lot to install it look for it on ebay and choose my answer like the best ok!

i would get a capacitor first, it works similar to a battery, it stores up energy so you don't drain your battery. but the best thing you could do would be to get a better alternator. batteries will work though, my friend was running over 6000 watts and all he did was put 2 extra batteries in his explorer. and it worked fine.