Your kinda half right in saying it doesn't add voltage to the system but...

Ohms law:

I = current
R= Resistance
V = Voltage

I = V/R

amps draw current with a fixed resistance in wiring. So as more current is required by the amp to supply its wattage this makes a higher amount of voltage neccesary to supply that current. Guess what, a vehicles alternator can only supply 14V max to the battery in which is only rated for 12 volts. Why? Quite simply the voltage regulator in the alternator. So how do we get that voltage? Well. Typical capacitors have a rating of 20-24 volts surge. This is what allows them to supply its extra current to the amp where the alternator and battery cannot.

If you were ever to measure the voltage right at the cap during operation you will see it can hit well over the 14 volts that is supplied by the alternator.

Yes by adding the cap to the system you are adding to the resistance and using ohms law that degrades the I draw to the amp, however because it stores energy that degradation of max current is negated for the most part. Assuming you are using the right size cap for the system.

Using ohms law as well, if you upgrade the battery cables to say a 0 gauge wire this adds resistance to the system as well. This is because for a given amperage draw the voltage will be higher. The higher the voltage the faster that power can be supplied.

 

It ain't too bad. 198amps@1230rpm. It probably doing 160amps or so at 700rpm. I am glad you posted the output sheet so I know that my 270XP alt making some serious power.

As for dual alt bracket, I have never seen one done on 4Runner before. If you can find it, let us know. I have one alt and two massive batteries that keep voltage pretty steady.

Capacitor are for weak. Get a high output alt and several batteries that will outperform cap.

 

lol yea, i have 3 xs power d3100s. the 270 xp is holdin up well and i know my currently electrical of those 3 bats and the alt will hold up without any problems, but i was thinking of adding another because i'm definitely gonna be doing more power in the future. as for my setup i have a sundown 3500 @.5 and a kicker 850.4 for mids and highs 4 6x9s and 4 tweets. doing 16 12's in a clamshell wall, 300 rms each wired series/parallel to half ohm(amp is half ohm stable and will put out well over 4k at .5). power and grounds are done in 3/0 welding. fused at front and back bat. my back bats will probably be a foot away from my amp. just been looking everywhere contacting dc power, mechman, ea, random other ppl lol.

*edit - i know i can keep adding batteries as i increase power but id much rather add another alt. sure id be able play longer with more batteries before voltage drop became an issue with more batteries but another alt would eliminate any voltage drop problems. lets say my system has an amp draw of 500, 250 continuous for music, id start drawing more than the alt could put out. (i usually only crank during idle, had 4 l7 12's in before and the shaking and pressure made it almost impossible to focus while driving lol). and this is only for my current setup. once i get out of college and ill be going up to something a bit more extreme. hopefully 10-15k

 

btw 4rx/ozim (guessing thats you over on smd) i managed to crammed a 3100 under my hood

 

btw, caps arent useless. theyre good for "smoothing" out voltage if your electrical system is already plenty for what you need. however the point of adding is another alt is for future upgrades when i up the watts im runnin

 

i was actually reading into the high idle switches 2 months back or so. how would i go about doing that? thatd be nice being able to switch it and have and idle at ~2k when i want. ill go look for it now.

 

seriously, post some pics of this system. not too sure why you need a 2nd alt.. my friend here in hawaii is hitting 154.x db on music (below 40hz), running a pair of sundown 3500s strapped at .5 ohm to a pair of nightshade 18s with 3 or 4 kinetik HC2400s. all of that is powered by a single H/O DC alt. he runs that system daily.

eventually imma have to pick up an alt and pair of batts for my little system. my fricken DLS A6 has some wicked amperage draw!

 

smaller pulley on your alternator?

 

im pretty sure my current electric is enough for what im gonna do. i remember someone quoted on smd something like "this forum has a boner for ridiculous electrical upgrades". guess i got a bit of that from reading so much on there lol. the 4 l7s and around 640 rated rms of mids and highs i was still dropping at full tilt.
i know its ugly, was testing the box and seeing how everything sounded before i cleaned stuff up. port ended up being too big


i pulled this setup out and going a different direction. in the process of building the clamshell box. subs are arriving tomorrow.

*edit - strapped at .5 for daily?! jeeezzzzz

 

hmmm... he also has a sundown 100.2 @ 2 ohm to a pair of rainbow comps, full tilt i havent seen the voltage dip below 13.5 from 14.4

 

weird...2 3500 strapped at .5 alone should have a massive amp draw. unless he has his gain pretty low i dont see how it doesnt drop. i talked to someone on a different forum who burped his at .35. thing was popping 500a fuses.

 

Is it possible to just beef up the one alternator? Also how bad does your runner rattle from the outside?

 

idk if you made some mistakes with which terms you were using, but there is a lot of fundamental mistakes with what you said above. I'm an EE myself... Capacitors don't add resistance. In fact, they are modeled as an open circuit - you wire them in parallel with the DC system. Capacitors will never provide more voltage than what is coming from the batteries/alternator, the 12-14 volts. Upgrading the wire gauge to larger wires DECREASES the wire resistance, which reduces the voltage drop across the wires coming from the battery to the amp. For the long cables from the front battery to the trunk, sure, upgrading wires will help some, but for the short 1 foot ground cables, etc, there is going to be little effect.

 

power, ground and big 3 is done in 3/0 welding. all terminals have shiny paint crap sanded off of it. as for the rattle i put sound deadening in the trunk door thinger (2 layers) and 1 layer in the front doors. right now only rattling i have is in the trunk. something near where the latch to open the trunk rattles pretty bad. dont think i can get a much beefier alt than this. they do have a 390 xp but its same at idle. upgrading to that would be about the same price as adding another 270 xp. positive and negative runs from front bat to rear bat are about 10-12 feet or so, ground is about 1 foot. im not desperate for a second alt immediately, but i know im gonna want another one when i up the watts im running, just think itd be good to prepare first. overkill on electrical never hurts

 

arent the nightshades rated like 1500 each? i know they can take more than rated but 4k+ for daily seems a bit extreme.

 

ya thats me over on smd. I can fit d3100 in the front but dont want to add 80 lbs on the drivers side lol I'd definitely add second alternator if go over 10k of powaaa!

 

i figured the bigger the battery i can fit the better lol. not too worried about weight just yet, although mileage has taken a hit. as soon as i hit 1000+ lbs of audio stuff i might cut it down a bit/do something about suspension. i tend to get ahead of myself with planning lol. start planning my next setup before i even finish the one im working on lol. anyways, im pushin to get alot done before i leave for break friday morning. ill keep posting on smd. keep an eye out!

 

well since we got onto the topic of my setup, ups man came over today and dropped a bit of stuff off.


if anyones interested in my build/how i got to my box design you can follow it here
http://www.stevemeadedesigns.com/boa...20cancellation