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I need some advise wiring up a 12V power outlet block like this:
The outlet will be powering a 700watt speaker tube, a gps, and occasionally a phone charger. I don't want to wire it directly to the battery because I need it to turn off while the truck is off, otherwise the amp in the speaker tube will drain the battery. My plan is to tap into the 12V wire leaving the ignition and ground it on the frame somewhere. Will the ignition wire be able to supply enough current or is there a better location to tap? Another option would be to wire it directly to the battery and then have a relay that trips when the truck is on, however I'm not sure if this is necessary or how I would wire the relay. What do you guys think?
Another much simpler option would be to pick up one of these, but I'm concerned there would be too much current draw on the factory outlet wiring and fuse with the setup I'm planning. Let me know if this isn't the case though it would save allot of time.
For reference this is the speaker system I'll be powering:
Best bet would be to run it on a separate relay triggered by a key on source. Even then, I don't know if I'd advise running a 700 watt amp off of the same circuit.
If the tube has its own remote wire, like amps do then you can wire that to your ignition so it will turn off with the vehicle.
I would recommend running its own wire from the battery, with a fuse, and possibly a capacitor in line. That is an awful lot to expect from a stock toyota alternator.
I would also look into getting a high output alternator, or doing a gm 1 or 3 wire swap. The later being a bit more advanced.
The "700 watt" speaker likely draws much less than that except at audio peaks. Average draw on a speaker is less than 1/10 the peak load unless you're playing pure organ tones through it at full volume. Your battery and alternator will handle the load just fine.
Those "cigarette lighter" outlets aren't typically rated for much over 10 amps, however. For best performance I'd recommend a separate 10 gauge wire and a 30-50 amp relay direct from the battery for the amp. The ignition circuit will be fine to power your other stuff through the outlet strip.
I honestly don't know how much current the speaker tube draws, its designed to be plugged into a cigarette lighter style outlet on an ATV so I don't think alternator work is necessary and that's why originally I wanted to have everything plugging into the same power strip. I could wire it directly to the battery and use a relay that's tripped by a wire to the power strip though if you guys think that's the safest way to do it.
That doesn't look like more than 16 or 18 gauge wire on that power plug. My guess is the "700 watts" is mostly hype, as is true with so many audio products. Average power is probably less than 20 watts. I think you'll be just fine wiring to the ignition wiring. Put in a 10 amp fuse to protect against excessive current draws. If it blows, you'll need to beef up the wiring. If not, you're good to go.
I searched around and found this Q&A on the unit. Because of the intended application (ATV audio) along with the cigarette lighter power plug and the small wire gauge, I also think that it would be fine to run the multi-outlet setup in your first picture. If you wire this to your existing cigarette lighter power source, which in my '90 4Runner is a 12V, 16AWG line with a 15 Amp in line fuse (normal for most cars) you should be safe to power the speakers, GPS and phone charger.
As others have said, if you start blowing the 15A fuse you will have to install a separate ignition activated relay/wire setup.
Feb 17, 2015 | 12:47 PM
only drops to a 50 amp draw 
