can this cause electrical issues?

Lights were off, journey was about 7km at 60-80km/h. Not sure about alt or battery yet, but the connections for the battery should be tight. I have a feeling it is a lousy wiring job. There is no reason, in my mind, for why the amp is still powered on. When I am playing it loud, no lights dim, no noticeable dip in V, and there is no sign of anything going wrong. It's only when the car is off.

IDMAX12V3 wrote: I even had a 'pro' install it. I guess this just goes to show that you should do your own work whenever possible.

No - the advice after that statement (before your reply above) is by a pro. I suspect you had it installed by a professional. Next time, get a real pro - not someone that is merely paid for doing it. (Relax Max - I'm having my usual go at "qualified" and allegedly expert people... Few of those on here, though there was one about to take an exam....)

I took it back today and they said that it was because I don't have an after market HU yet and there is no remote switch on the stock one. They hooked it up to my AUX power, but now when it turns off, there is 'pop' and then it comes back on about 15 seconds later and then goes off again. I'm going to just get my TV installed sooner than expected and see where that takes me.

The answer they gave you is no reason for doing what they did. They should have informed you of the situation at the time of the original install. They must have known that wiring the amp like that would lead to grief. I'm also sure that a couple of people on this site have the answer to the popping, or if you have a screen antenna rather than a rod, there WILL be a switched output SOMEWHERE on the head unit. I don't know the vehicle or the head unit enough to comment, but, back in the early 70s I remember soldering to the backs of the volume controls on the old push button radios.

What can I say...? There is NEVER a pro around when you need one. EXCEPT on this site. (The pot soldering was to earth/ground the housing to avoid static buildup of interference. But that was when components were analog... (lol))

upgrade your battery add one or more batteries upgrade your alt upgrade your ground and charge cables upgrade all cables going to and from battery to battery and battery to amp 4ga /0ga that amp with that woofer pulls a lot of current if you are playing your sub while driving alt not charging fast enough while sitting no charge left also check if the inside of your cables are green and since you probably have side post make sure the connection to battery is not rusted or looseabethebue

IDMAX12V3 wrote: I installed the sub and amp into the car and it rarely dips below 14V, but as soon as I turn the car off and play music, my battery last about 5 minutes. I've been hearing from people that a second battery is more important than a HO alt. Also, I don't know where to find a decent alt for a fair price. Any suggestions?

If you do add a second battery, then isolate it from the starting battery with a diode isolator (or build your own relay isolator) and run all your audio equipment and aux. wiring off the isolated battery. That way you can drain your aux. battery but the starting battery will have plenty of juice to start the motor. I also think that a deep cycle battery would work best as your aux. battery. It does not have the CCA of a starting battery but it handles deep discharge very well and can just be recharged. But the alternator is what makes the power, a battery is mostly there so you can start your motor.

Good to see those Viking Gods are on the ball! Call me a pagan, but I too believe isolators to be essential. (Actually it's not a belief - it is knowledge, but I let live. And let die.) Though I reckon diode isolators are "the worst" type for heavy currents etc. (Plus no battery is on the same rail as the alternator...) Even "smart" (aka voltage sensing etc) isolators are preferable IMO. But the only time a "smart" isolator is warranted is when there is no charge light - as with permanent magnet rotor alternators etc (marine applications etc). Or if people prefer spending money on a "transportable" device rather than finding which wire is the charge-lamp circuit. But for those with a charge light, it's usually a case of adding whatever capacity relay you want - whether 30A or 300A. (Big relays may need a intermediate relay or FETs so they don't overload the alternator/regulator's charge lamp circuit.) Heja Tor!