Flickering headlights with an earthquake phd2

[Sinister7]

Hey all. I'm going to start this off from the beginning. I have a 1999 BMW 328i that has a 120amp Valeo alternator and a brand new battery 1000 cca battery. I have 2 10" mtx 600 watt jackhammer subwoofers run in series and an earthquake phd2 amplifier. Not to sure ohm ratings and whatnot. Also the wiring was all re run 0 gauge for power with a 5 farad cap. The battery on this car is located in the trunk on these cars but there can be a second battery installed if needed. Now the problem is everytime I turn the bass up on my alpine head I get flickering headlights and interior reading lights. Soon as I turn it down with a little bass it's fine. Now doing just a draw test with the bass super loud I was getting an intermittent drop sometimes to .9 volts but for the most part it was staying at 14.1v charge. HELP!!!!

 

[Perry Babin]

A drop of 1 volt will make a big difference. The alternator probably doesn't have enough output current to keep the headlights from dimming. Even if it does, there's a bit of lag built into the regulator that will prevent it from keeping the voltage precisely at 14.1v all of the time.

 

[Sinister7]

Thanks. Is there another way around upgrading the alternator? Is a second battery going to make any difference?

 

[Perry Babin]

A second battery probably won't make a difference. All real solutions are going to be expensive. Upgrading the alternator isn't necessarily going to solve the problem completely.

 

[Sinister7]

What's the best solution in your opinion?

 

[Perry Babin]

How do you define best?

 

[TheBaronGroog]

Try whichever is cheapest 1st-check with BMW whether a larger altnerator from a higher model will fit and compare that to the cost of a 2nd battery-ultimately both is better. Try removing the cap-sometimes they can do more harm than good.

 

[lowered98z24]

caps only store some power but do more harm than help from what i seen.if it was me i would do the big 3 upgrade and if it still is having the same issue then its safe to add the 2nd battery.if u are unsure of how to do a big 3 it walk u through it on youtube.hope this helps

 

[Sinister7]

Well I have ripped my alternator out and sent it to the rebuild shop. The brushes and slip rings are worn right out of it. So I am going to attempt a rebuild on that first. Also adding a second battery wont be very expensive at all. I got one lying around my house and there is a special place for one under the hood in the front of the car on these. I guess it was an option to have them up front from the factory in europe. All i need is the cables and battery tray.

 

[Perry Babin]

Extra batteries won't generally help unless the voltage is dropping to below 12v. Even then, they won't help much. If the alternator charges at 13.8 and the voltage drops to 12v, the lights will dim significantly.