I added an amp and sub tonight to my car. I have a Kenwood KAC-7204 amp bridged powering a KFC-3011 12" sub. My lighting dims when my bass hits. It has a 40 amp fuse in it so I am thinking upgrade the battery should clear up the problem, but I have never had a vehicle that did this. Iwas wondering which I should add first a capacitor or a optima battery?

 

honestly, either one will work. I have a 3 farad cap and it works very nicely. Im really impressed, I get no dimming. The battery will be more expensive, but, if yours is about due for a change then go for the battery.

 

You think a red top optima will do or should I get a yellow top instead?

Also I took a voltage reading at the amp and at the battery. With my volume up to about 20 I start to notice my voltagevary from the normal 14.25 to 13.56-14 volts. If I turn it up more then it really starts to stay below 14. Is this a sign of to much draw on the charging system, and not the battery? The amp is not wired direct to the battery, but to the accessory post on the fuse/relay box under the hood. Is this right?

I don't want to burn out my charging system just to have an amp.

 

I got another question that I am not sure of the answer to. The installer attached the amp to the accessory post on the fuse block. Is that right? Shouldn't the amp be attached to the battery directly with a inline fuse?

 

i am no expert but i have never seen an amp being run of the accessory post any car i have seen they always just have an inline fuse and directly wired to the battery.

 

Wire it directly to the batt and don't use a capacitor. The guys on the car audio forum will tell you that you will see a much bigger gain with a better battery than you will with any cap. If you have the skill, I would put an optima in the trunk and still use the regular battery up front.

 

anything short of upgrading your alternator to a higher output model would be akin to putting a band aid on a wound that needs stitches. I'd upgrade the Big 3 first, then upgrade the alternator.

 

I ran 2000 watts and 4 12's in a honda civic. I use a capacitor and did not have my lights dim at all. They would blink before hand. I was hiting 141-143 in the db drags I was competing in with just 2 12's. For me the cap made a world of difference.

 

There are situations where it would, such as if the draw on the system was slightly exceeding what the alternator could handle, it all comes down to how much current your alt can put out and how much current is needed. If your alt puts out 65amps, yet you're pulling 100amps to your bass amp alone, a cap won't do any good. So the first thing anyone should do is some simple math; know how much your alt puts out and figure out how much of a draw there is on your system and go from there. No need to take a cannon to a knife fight and a waste of time trying to reattach your arm with a band aid. So I concede that I jumped the gun in suggesting an alt off the bat not even knowing what the pertinent numbers are. But either way, make sure you upgrade your Big 3 before you do anything.

 

Upgrade the big 3 ONLY if you are doing an alternator upgrade, otherwise, it will do nothing for your problem.
Again, this is a difference of opinion here. But a capacitor is nothing more than a short term voltage storage device. Upgrading your battery to a minimum of a deep cycle battery will help, but a second battery is better. Turn off the motor and see how long your stereo runs. You need to have your motor running to listen to your stereo? Not me! My lights don't flicker, either.
Your stereo should NOT be wired to your fuse box, NEVER!
Again, I relate this to my snow plowing experiences, plowing at night. Stall the truck with one battery, and you are calling for a jump start. Running a second battery with an isolator solves this problem. One battery runs the truck, and one runs the plow. Stock alternators.
There is no such thing as too large of a battery.