Possible battery issue, or possible alternator trouble?

Question

Looking for a few well educated answers, as I'm stumped. I have my stock alternator, and a normal battery, powering my sound system. 1800 watts of power to the amps, but there's a 5 farad cap in the hook-up also. The car has been sitting in storage over the winter, and the last 3 months because of a recent license suspension. Now, due to my negligence, the battery has gone stone dead twice in that time span, but was fully charged afterwards. Now while driving, after several minutes of playing, my cap starts to whistle and all my dash lights cease to function, while me head unit powers down. My tack and speedometer cease to function aswell. My question is simple: would this issue be resolved by purchasing a new battery? One better suited to my system, a yellow top optimum for instance, or is my issue deeper yet? Will the alternator need replacing? Keep in mind my current set up worked just fine until the battery died those two times, so my alternator was doing fine coping with it before

Answer 1

charge your battry again atleast 4 hrs take it 2 autozone and have the charging/starting system check they will do it 4 free and let u know what needs replaced

Answer 2

Here's a quick way to tell if it is the battery or the alternator, or both.

Get a digital multimeter. Set it to volts DC(20v, if it's not auto ranging).

Charge the battery and take a baseline test of the voltage. It should be around 12 volts but not under. If it's under or if the battery voltage drops over time then the battery is bad.

No matter what, move onto step two. Start the car and take another reading. It should be around 14 volts. If it's not, or if the reading is lower than the previous the the alternator or voltage regulator is shot.

From the sounds of it. The alternator will need to be replaced.

Answer 3

It's nice that you have a capacitor, but we need to get past the misconceptions of them first. They are designed to supply a jolt of energy for a very hard bass note at a short burst. When a car is running, the majority of electrical things rely on the alternator. The only time the battery comes into play is when the alternator is short on energy. When adding a new system the first thing you'll upgrade is the alternator. I'd bank on this solving your problems.