Help On Required Elctrical Upgrades

[B-Large]

I'm in the beginning stages of a build on a 2006 passat (140 amp stock alternator) currently with oem battery. I will be running two channels of and Alpine pdx 4.150 @ 4 ohms (estimated 30 amps) and A Rockford T-1000 BDCP @ 2 ohms (fused @ 150). The intent is a musical/ daily setup for a single 12' sub and one 6.5" component set that will have good sq but can occasionally get loud (I.M.O). Wiring will consist of big three and 0 gauge to the trunk with 4 gauge to the amps.

Would 4 gauge be enough for big 3?

Do I need a high output alternator?

Is multiple batteries required, or would an upgrade under hood be sufficient?

[hdorre]

I'm in the beginning stages of a build on a 2006 passat (140 amp stock alternator) currently with oem battery. I will be running two channels of and Alpine pdx 4.150 @ 4 ohms (estimated 30 amps) and A Rockford T-1000 BDCP @ 2 ohms (fused @ 150). The intent is a musical/ daily setup for a single 12' sub and one 6.5" component set that will have good sq but can occasionally get loud (I.M.O). Wiring will consist of big three and 0 gauge to the trunk with 4 gauge to the amps.

Would 4 gauge be enough for big 3? For the stock alternator, yes.

Do I need a high output alternator? ​I wouldn't bother

Is multiple batteries required, or would an upgrade under hood be sufficient? I would run the biggest AGM you can under the hood, and a small one in the back.. Im talking like XS D975 size

[B-Large]

Thanks hdorre. That is what i was hoping to hear even though that may be $450 to $500 worth of batteries.

Would you recommend under hood first if funds don't support both?

[Amart88]

Thanks hdorre. That is what i was hoping to hear even though that may be $450 to $500 worth of batteries.

Would you recommend under hood first if funds don't support both?

Yes, for the fact that many aftermarket agms rest at a higher voltage than your factory battery. Therfore it would leech off of the added agm in the back. I would start with the under-hood first.

[hdorre]

Thanks hdorre. That is what i was hoping to hear even though that may be $450 to $500 worth of batteries.

Would you recommend under hood first if funds don't support both?

Yes sir. AGM batteries rest higher than Wet Cells (what most stock batteries are). Basically, the batteries try to "level out" voltage. This hurts your AGM battery by dragging it down.

Lets take a realistic example.. Lets say that your stock battery rests at 12.6 volts and your AGM rests at 12.8 volts.. Once the batteries "level out," you'll be resting around 12.7 (give or take a few hundredths of a volt).

You may be thinking, "wtf, its only a tenth of a volt." Think about how often your car is off (batteries rest). Over time, it hurts and you can expect a shorter lifetime for the AGM.

Thats a generic explanation.

[B-Large]

Thanks hdorre. That is what i was hoping to hear even though that may be $450 to $500 worth of batteries.

Would you recommend under hood first if funds don't support both?

Yes sir. AGM batteries rest higher than Wet Cells (what most stock batteries are). Basically, the batteries try to "level out" voltage. This hurts your AGM battery by dragging it down.

Lets take a realistic example.. Lets say that your stock battery rests at 12.6 volts and your AGM rests at 12.8 volts.. Once the batteries "level out," you'll be resting around 12.7 (give or take a few hundredths of a volt).

You may be thinking, "wtf, its only a tenth of a volt." Think about how often your car is off (batteries rest). Over time, it hurts and you can expect a shorter lifetime for the AGM.

Thats a generic explanation.

Makes sense. Assuming batteries were both agm with same resting voltage would this be a correct/safe setup?

http://imageshack.com/a/img824/923/36ti.png

[Amart88]

Thanks hdorre. That is what i was hoping to hear even though that may be $450 to $500 worth of batteries.

Would you recommend under hood first if funds don't support both?

Yes sir. AGM batteries rest higher than Wet Cells (what most stock batteries are). Basically, the batteries try to "level out" voltage. This hurts your AGM battery by dragging it down.

Lets take a realistic example.. Lets say that your stock battery rests at 12.6 volts and your AGM rests at 12.8 volts.. Once the batteries "level out," you'll be resting around 12.7 (give or take a few hundredths of a volt).

You may be thinking, "wtf, its only a tenth of a volt." Think about how often your car is off (batteries rest). Over time, it hurts and you can expect a shorter lifetime for the AGM.

Thats a generic explanation.

Makes sense. Assuming batteries were both agm with same resting voltage would this be a correct/safe setup?

http://imageshack.com/a/img824/923/36ti.png

You should just do one run of 1/0 from alt to front battery instead of the 2 4 ga's. seeing how you are running 1/0 the rest of the way. Also, you can add a 1/0 ground to the alternator.

[hdorre]

Yes, that would be the correct wiring setup. Just make sure your grounds are good.

[hdorre]

You should just do one run of 1/0 from alt to front battery instead of the 2 4 ga's. seeing how you are running 1/0 the rest of the way.

One of the lines is the factory wire, and the other is his 4awg (for the big 3). He has a 140A factory alt, and 4awg is more than capable of carrying that current.

[Amart88]

You should just do one run of 1/0 from alt to front battery instead of the 2 4 ga's. seeing how you are running 1/0 the rest of the way.

One of the lines is the factory wire, and the other is his 4awg (for the big 3). He has a 140A factory alt, and 4awg is more than capable of carrying that current.

My bad. Just noticed that. Don;t touch the factory wiring. Add to it if need be. Yes it is capable. I just thought seeing how he will be using 1/0 for his runs, It couldn't hurt to have it at the alt also. In case he ever upgrades the alt down the road he would not have to worry about it. Either way would be fine