anybody now how to hook up 2 batterys at the same time in the trunk? i hooked up a system up in my friends car and it drains the power from one battery, and he is to cheap to buy a Capacitor.
Tell your buddy to upgrade his alternator. Hooking up another battery is just placing another load on to the already under powered alternator. Trust me, it would be a waist of money. If he has a stang, buying an upgraded alternator is only going to cost him about 150 dollars and besides having enough power for your system, his lights and other accessories will be much happier to. later
Tom is absolutely right... but, connecting positive to positive and negative to negative will yeild 12v with double the amps. What ever you do don't put the pos to neg like in a flashlight. You will fry the electrical system. Also make sure both batteries are fully charged before you connect them. You can easily kill the alternator trying to charge them both at the same time and run the car.
However, all this will do is take longer to drain if the alternator can't keep up. You MUST upgrade the alternator to have a reliable set up. A capacitor is used to "stiffen" the supply for low frequency transients (read: bass) and as a filter for any ripple the DC may pick up. Putting another battery will help, but not corect the underlying electrical issue of the insuficient amperage output from the alternator.
Exactly right. If you have two batterys, even if they are identical, they will never be at the exact same power level. When the car is not running, they are gonna fight. That which has more power will drain into the one with less power, and that will continue back and forth. Everytime that happens, they both lose a little charge. It takes energy to transfer energy.
"Power follows the path of least resistance"
With a battery isolator, they are only connected to each other when the car is running. This is good. Then the alternator is powering the car and charging the batterys. They don't have to fight for power.