system not getting power it needs

Car details,

Honda Passport 99' EX 3.2L Engine88Amp Alternator (Stock) tried 180amp Alternator (since removed)Duralast Gold Front Battery4awg from Front Bat to Back BatYellow Top Optima (not isolated) Back Battery4awg Grounds and 0awg Alt > Bat Wireing in EngineSytem details,850w RMS Kenwood 9102D Mono Amp2x 400RMS Kenwood 12'100w RMS MTX Audio 2 Channel Speaker Amp2 farad Tsunami Capacitor wired next to Sub AmpProblem,My voltage dips down to 11volts, now before you say somthing, keep in mind I upgraded my alternator to a 180amp (excessive amperage) alt.  It did not fix my problem, it seemed to help but still got down to 11volts in the end.  It would probley go further except if I turn it any louder my amp shuts off becuase of the DC signal Clipping.  Now some details on the new alternator, I was recommended to test it, and I did.  When it was tested at a local high output shop they said it did 101amps inside the car and 130amps outside the car.  I mailed back the alt, I was told by excessive amperage it was operating perfectly (14.8 volts and 180amps).  So I don't know if he was just trying to screw me or if there really was a problem.  I've since returned the alt, and got my money back.  If the alt was truely not functioning correctly this can explain as to why I got a little boost with the new alt.  But still can't play my system at its potential power.As stated above I've tried the following,Adding a new HO alt, Removeing the Second Battery, Adding a Second Battery, Changing all my Grounds in the Engine area (made no difference), Fully Charging both Batteries (using a tickle charge overnight), having just the subs hooked up.I've been told by everyone that the power im running shouldn't be any problem for what i've tried to use.  I've had my grounds checked, there all fine.  And with all the upgrades i've made it should have fixed the problem.

What else am I missing here?  Does anyone have any ideas what I can do to solve my low voltage (effectivally low voltage = not enough power to give = not enough amperage?)

Thanks

Btw, my idle voltage is 13.8, when everything is running at idle (lights, air, etc) it can go as low as 13 at idle (oddly enough if the car is in park I get 13.8 at idle, if I pop it in drive or n I notice the volts will drop even lower (12.8ish).  I never see 14v (exactly 14) unless the car has been off for a long time).

I also fused the alt to bat with a 200amp, and im running a 100amp fuse from bat to amps.

You said you upgraded the engine bay grounds, but what about the alt to bat wire? this needs to be the same size as your battery to chassis and engine to chassis ground. I recommend 4 gauge minimum. upgrading the three wires i mentioned is "The Big 3" that DYohn mentioned.1999 Toyota Camry

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Pioneer DEH-P3700MP

Lightning Audio Strike S4.15.VC2

Lightning Audio Strike S4.500.1

Majestic 6.5"

Answers to questions.

1.  The power at rpm was no difference, it just made the voltage just a little bit steadier, this was with 180amp alternator btw.  But in the end going from my 88amp alt, to my 180amp alt (technically) only seemed to make a 20% difference in volume.2.  All Big 3 have been upgraded, and im using 0 gauage.3.  The max TESTED output that I could find was 130amps, but I mailed it back to the guy that built it and he said it was operating fine.  So I don't know if he overrated it and wants to cover his tracks.  He said some people don't have the right tools to test a high output alt to its full load capacity.