Try using a capacitor.
Sent from another garage.
Hey guys I'm back again. Sorry to bother all of you with my problems so often. As most of you are probably familiar with, I have went and installed lc7i and two amplifiers, one (Dual BAK 100watt rms x 4 at 4ohm) for door speakers and one (Kicker CXA1200.1 amplifier) for my 12" Q class 900watt rms Kicker L7 . I have been trying to tune my subs properly, with DMM. Am able to get about 40V (800 or so Watts RMS) with 45 hz test tone/songs before amplifier goes into protect mode and subwoofer stops playing. This first time this happened I was playing a 40 hz test tune and thought I blew the sub and dang near had a heart attack. Crazy thing is, is that it wasn't anywhere near the 1200 watts rms the amplifier is rated at...This leads me to believe my amplifiers are trying to draw too much power from my stock battery which cannot feed the two amplifiers sufficiently and my sub amplifier is going into protect mode because of this on hard power sucking bass. This happened playing songs before, but I thought it was just a bad ground (also had feeback to speakers thinking it was ground related(Separate headache)) so I changed it from stock sub stud in hatch to the seat bolt with paint all sanded off. Had a local stereo shop even change ground a third time and I wasted my money taking it there. I therefore do not believe it is a ground issue.
My headlights dim very badly when bass drops as well as my accessory lights if on.
If my door speaker amp is drawing 400 watts RMS and my subwoofer amp is attempting to pull 900+, that is 1300 watts RMS my stock battery is trying to supply.
Am I right to assume I should be addressing a power related issue?
Can I simply add a small AGM car audio style battery to my trunk to try to resolve the issue while keeping my stock battery?
Would I need a 1600 watt rms rated battery, or could I add a smaller rated battery and not use an isolator so I am technically using both batteries to power the amps? Is that a thing?
I'm sure I have many other questions that will pop up, but if anyone has done this or has any insight I would appreciate it!
Last edited by boostinburgh; 03-24-2019 at 03:23 PM.
After watching this video, which states stock batteries/electrical on vehicles can only take 700-1200 watts, I can see I do need a second battery.
The question then becomes do I need a battery rated for 1600 watts or can I get a smaller one to work in conjunction with my stock battery to add up to the 1600 watts rms?
If so what output is stock battery to reference the size I will need to buy for secondary battery?
This is a problem I'm going to run into when I install my system how much has I have 260 amps of fusing for my amplifiers and stock alternator only puts out 150 amps. You can try what I'm going to have to do. I plan on putting a yellow top under the hood a 94r equivalent which is a larger battery you remove the spacers in the battery tray for it to fit and modify the hold down bar. Then I'm probably going to have to put an audio battery in the trunk. I also have a 50 farad hybrid capacitor capable of 20 volts. And then the Big 3 under the hood. All 0 gauge wire. Get the least amount of resistance possible.
the stock alternator on focus ST's is 150 amps. which should be more than enough to support your setup. i had a rockford fosgate 600w 4 channel and a rockford fosgate 2500bdcp on the stock electrical with no issues really.
do you know how bad your voltage drop is? if not, measure it.
what size power/ground wiring are you using?
how old is your battery?
are you wired to a supported ohm load on the amp? your kicker amp can only be wired down to 2 ohms. if its wired at 1 thats an issue.
your positive power wire should be going directly to the battery terminal.
edit: do NOT use a battery isolator. please.
I will measure voltage drop tomorrow
Battery is 2 years old