Added cap and 4 gauge and dimming got worse?

[justsayk 10+ year member]

Ok, i had 8 gauge wire, rewired with 4 gauge, and added a .8 farad cap (it came from a big variable power supply at a junk store for $5). I turned the car on, turned the system up, and now i have almost no headlights when the bass hits, and after about a minute my battery light on the dash flashes and everything almost shuts off. Why would this be? The 4 gauge would allow more current to flow from the battery to the amp, but i would think the cap would at least cancel that out. Even if the cap wasn't working i wouldn't think it would dim that much. I've only got a 500 watt bazooka amp and the gain is roughly half way up. What da problem is?

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[Ricktc 10+ year member]

Get rid of that junk cap and try it without. Likely chance it will get much better. If not, dimming isn't that big of a deal anyways.

 

[Trixter 10+ year member]

Agreed. Keep the 4g wire and ditch the cap.

 

[justsayk 10+ year member]

Alright thanks...my car is also haveing some starting problems now...could my alternator be going? How much for a good alternator?

 

[iamamp3pimp 5,000+ posts]

battery is dying i bet

 

[wags 10+ year member]

yeah get a new battery (deep cycle if possible) and see if it makes a difference.

 

[DBfan187 5,000+ posts]

tsk tsk tsk, you got a cap!

 

[biteablegravy 10+ year member]

You're seeing a bigger voltage drop now because after the cap discharges, it draws power directly from the battery to recharge it. So your battery is powering both the amp (when the cap discharges) and the cap itself. Not to mention all the electrical draw coming from the car (headunit, headlights, all the guages, computer, etc).

When used correctly, a cap can be beneficial. If you just slap it on a stock electrical system and expect it to fix everything, you're going to be looking at a dead battery and a dying alternator.

Ditch the cap, replace your battery with something better than stock, and then see where you're at.

You really shouldn't see that much voltage drop with the power you're pulling, so a new battery and possibly a new alternator should be all you need.