snafu

Sure, that works fine. I reference the frame in such vehicles for all return path connections for high powered accessories.

OK, let me explain why in my near 30 years of building car audio systems, I've never run a ground from the amplifiers to the front of the vehicle to connect it to the battery negative. 1. That cable will have greater resistance over it's length than correctly utilizing the frame of a vehicle, like say a truck. 2. Should the stock battery negative to the block come loose, lose integrity, or become otherwise a botteneck, the starter will source current from other ground paths. If you had no audio system, that could be from the bell housing to the firewall (via the braided ground strap most vehicles have) and then back to the battery negative via the accessory ground lead between it and the inner fender or core support. Over time, one or both of these grounds can become damaged from this excessive current. Let's say that the ground strap from the bell housing snapped - new return path could be via the transmission kick down cable or throttle cable. In my time, I've seen it all happen and people will often continue to drive a vehicle like this until it simply won't start. Ever seen a throttle cable burned in half? Now, let's just say that one installs a killer audio system and does run a nice big ground cable to the battery negative. Forget about whether it's better or worse than the frame for the audio system. Think about how this could function as a return path for the starter - for example, let's say that the accessory ground wire between the battery negative and inner fender was snapped because the connection between the battery negative and block came loose and what I describe above just happened. Here's the new return path for the starter: Bell housing to firewall, firewall to fender mounted antenna, antenna to radio, radio to amplifiers via RCA cables, amplifiers to battery negative. Not much survives. Guys, I will challenge you to make decisions that are safe choices - and not just because you heard someone tell you a friend told them on the 'net.

So, what happens to your audio equipment when the cable between your battery and engine block proves to be higher in resistance than the return path via your audio system? IE - corrosion and oxidation break down the termination over time, a piece of road debris hits the cable and cuts or damages it, or someone cuts it in a theft attempt of your vehicle? Consider the return path for the starter then . . .

CA260s! Wow . . . 60 wpc or 180 watts bridged . . . and like $500 each in the day. Not many of them still in use . . .

Have you tried calling them? Email is probably the most difficult thing for a busy company to keep up with.

http://www.autoworldnews.com/articles/1784/20120616/nissan-unveils-world-s-loudest-car-stereo.htm That's pretty damn cool!

Nicely done Steve! I like the "grocery plugs" . . . I was like . . . grocery plugs - huh? I'm glad the fan controller worked out for ya'. Hurry up and get that thing done so you can road trip it to PHX.

No problem. I've gone out of my way to make it EASY!

LOL . . . it's hot here too! Here's what I don't understand about this. If you cut the harness and have each half of the harness, how can the wiring not match up? www.mitchell1.com will have the data you're looking for, but you will have to pay to access it.

Just let me know how I can help.

Ray-ban, were you aware that I build and sell Big 3 kits that include full color step by step instructions? Not only are they easy to install, but they are also reasonably priced. Visit my forum here at SMD, or my web site (http://www.ceautoelectricsupply.com/big3kits.html) for more information.

Thanks. I build all kinds of stuff that isn't featured on my web site. It's hard to take pics of most of it because I'm usually against a deadline on completing the work.

That's a pretty cool location for those batteries, but I agree that it would be better to have them better protected. Looks like you'll need about 235 amps or so to supply those amps at 14.4 Volts DC on music. So, you may consider a larger alternator than what you are considering. Call Mechman or click on their banner . . . As for the electrical side of things, I can certainly help you there. I offer pre-made Big 3 kits and they are designed to make connecting additional batteries a snap. I can build any / all cables for you to your specifications if need be. Click on my banner to visit my web site or visit my forum here at SMD if you like.

Steve, VERY well done. If you can dream it . . . you can certainly build it. I LOVE the way this install is progressing!

Useless - hardly. Each has it's own merits.

OK alright . . . we'll just chalk it up to the fact that you owe me a cold frosty beverage . . .

Do you need my PayPal address to send me royalties? LOL!

FYI - a really slick version of this exists here: http://rockfordfosgate.com/Support/rftech.aspx#ampcalc Tony D', I, and Eric Russell developed it while I worked there.

Yeah, I gotta' get my web development guy off his lazy ass . . . hey SELF . . . get off your ass and get this done . . .

Math. 3,875 / 75% amplifier efficiency = 5,166.67 Watts Input 5,166.67 Watts / 14.4 Volts DC = 358.8 Amps Required to reproduce sine waves at full output 358.8 x 50% = 179.4 Amps Required to reproduce music at clipping If you'll be listening to music with this amp, then . . . Alternator size = 179.4 Amps + Stock Requirements + 10 Amps for each additional battery (3 Amps for each XS Power Battery) + 20% buffer Otherwise, use the BIG number . . . Methinks it's time to make a calculator and stick it on my web site . . .

That's ludicrous.

Your amp isn't going to pull 200 amps on music. Music has duty cycle. If it makes the rated 2,100 watts RMS into 1 ohm, that translates to about 91 amps with music assuming 80% amplifier efficiency. Double that for test tones.

FYI, 1/0 AWG has a resistance of .0001 ohms per foot. At 1,000 Amps, voltage drop across a 3 foot cable would be calculated as follows: E = R X I E = (.0001 ohms X 3 foot) x 1,000 Amps E = .0003 x 1,000 E = .3 Volts .3 Volts / 14.4 volts = 2% - just under the 3% guideline that I typically go by. Of course, this assumes your terminations on either end of the 1/0 AWG cable are rock solid, as well as the connections holding the lugs to the distribution block and vehicle chassis. Obviously, you will not be passing any where near 1,000 amps through this cable as your alternator would have to be large enough to supply that. So, I'm thinking that'll be a non-issue.

A single 1/0 AWG ground of a short length won't be the kind of limiting factor you may think. The dealer will tell you that your electrical modifications are the reason why it is not working correctly currently. They will be correct. Look at it like this. The water meter on your house is on the main feed - all water that is used in the house must pass through it. Therefore it's reading is exact. If you want this circuit to work correctly in your vehicle, you will have to adopt a similar philosophy.

Well, you have numerous connection points between the charging system and ground now. Stock, the inductive ring around the ground cable was able to monitor the state of the charging system via the battery's ground cable. This is no longer possible. I have not worked on one of these vehicles yet, so I do not have first hand familiarity with this arrangement. However, it would make the most sense that you isolate the ground distribution block from the vehicle where you currently have it mounted. Then, I would reference ALL grounds to this block except the alternator grounds - stock battery (if it is still there), aftermarket batteries, amplifiers, etc. You would then connect a single 1/0 AWG cable from the distribution block to the chassis of the vehicle, passing this cable through the ring. As for your alternator grounds, you may be able to connect them to the same point at which you have this main cable connected but you won't be able to tie them to the distribution block. Look at it this way, the only way the PCM can monitor the state of the charging system is to have a similar arrangement as what the factory laid out. As far as your alternator is concerned, everything you have added is simply a load. Best of all, this would be fairly easy to do. I make no promises as again I have not worked on a vehicle with this arrangement. But, I believe what I've laid out will get you in the ball park.