any electrical engineers out there?

[codyhoover]

here's my system<BR>panasonic CQ-DFX972U cd deck<BR>2x alpine mrp-t130 90wx2 <BR>1x lightning audio 400.1 400wrmsx1<BR>4x cerwin vega vega series 6.5" coax<BR>1x infinity perfect 12"<BR>4gage power down driver side to fosgate 1 farad cap+ to distibution block and 8 gage to amps<BR>8 gage grounds from amps to distribution block then 4 gage to cap- then back down center to bat-<BR>3 sets rcas down pasenger side to amps<BR>deck regrounded to battery ground on chassis <P>and now the problem<P>i know a bit about electrical sys but this is f**king wierd. when the car is off and the stereo is on after about 3 or 4 min the sound gets really quiet and shitty sounding when the sub hits. i think when the stereo is on with the car off the cap discharges and wont recharge until the car is turned back on because if i take the cap out after playin the stereo for a few min with the car off it's only holding about 2~2.8v it but that makes no sense to me at all. any thoughts? <P>oh yea the alternator pushes 13.9v and the bat is 13.6v with car off. i dont have a monitor top. the cap will stay charge out of the sys(which is normal) but it discharges while still in the system and cars off.

[Sonicxtacy02]

NOT an electrical engineer... but...<P>without the alt recharging the battery its quite common that you experience weaker sound from high power systems. If you really need to listen to music with the car off either get an optima yellowtop battery or something equiv.

[mr.hunt]

As mentioned above it is a high powered sys so the battery is probably having a hard time to keep up maybe look there first. Also to consider how is the wire supplying the power is it restricted or pinched. But I would think that the system is sucking the power and the power is not getting regenarated. even when testing the battery are you testing when you first start the car or shut it off maybe try to run the system then check your output i v. hope this helps

[tk1138]

EE rules!<BR>How is your Cap hoked up? if it's not connected to the battery when you are running with the car off, then that's your problem.It's just not getting recharged.<BR>If you wan't to run your system without having your car on, you'll need a second battery (dry cell/deep cycle) to run off of. Hard to diagnose without looking. Also <P>If you are going to run a ground wire from your amps back to the batt, then run it right next to the Supply wire, and ground it to the chassis at the ground distribution block as well. <BR>Also run the power directly to the distribution blocks, and have 4 guage to the cap from the distribution block.<BR>If you haven't already, upgrade the wiring on the alt and battery<P>Running the supply and ground wires next to eachother is important. If you ground to chassis, then running the supply close to the chassis is less significant, but is still a good idea (farady cage and Back EMF). <P>HTH<BR>tk1138