Mounting battery in the trunk questions, electrical questions...

[brads70]

Ok first off, electrical is not my strong point. I have various electrical aftermarket add on's  , fans, fuel pump, MSD, trans controller, etc....
I have a 95 amp alternator that won't keep up and drained the battery on the way to Carlisle. So I bought a 250 AMP , one wire hook up alternator. I know it's over kill but I'm done pissing around and might add other electrical items in the future like FI etc...
http://www.qualitypowerauto.com/catalog.php?item=557 and will be mounting the battery in the trunk for various reasons.

Using this amperage calculator http://www.qualitypowerauto.com/pages/AmperageLoadCalculator.php it says I need 145 amps with what I have now
Using this chart it says for 20' and 250 amps I need 3/0 gauge wire?  Is this right?
http://www.qualitypowerauto.com/Wire%20Sizing%20Chart%2012V%20DC.htm

I already have this http://www.painlessperformance.com/webcatalog/lv.php?sl=80115 mounted near the stock battery location and have a heavy jumper wire going to the battery.
Here is where I need help....
What I'm "thinking"... running the 3/0 gauge wire from the battery in the trunk to this distribution block. Then a 4 gauge wire to the alternator lug
( stock alternator hook up on the lug as well) Then cutting off the battery terminal and mounting the wires to the distribution block.
Does this sound like the correct way to do it?
After that is done I then plan of removing all the non stock wiring and running it all to a separate fuse box like this one.
http://www.bluesea.com/products/7748/SafetyHub_150_Fuse_Block
and mounting it in a sensible location where I don't need a chiropractor after I check a fuse! 
This years winter project! 
At some point I'd like to swap out the stock ammeter for a voltage gauge but anyone know of one that goes in a non ralley dash for a 70 Challenger that has the correct fonts that says " Voltage" ?

[Chryco Psycho]

I use welding cable , available in 4 or 0 ga from Princess auto or other places , generally I have used 4 ga with no issues  , flexable , well insulated & will carry serious current reliably I run 1 wire from the battery + to the main starter terminal Then run a 8 or 10 ga wire to the start relay from the same terminal , so you can jump to the distribution block instead & use a heavier jumper .
 You do not have to eliminate all the factory fues but the extra fuse block is great fro supplying power to all the add ons .
  I run the negative cable forward to the trans mount so there is no loss between the engine & battery , I also run a pigtail from the - terminal to the body for everything else to be grounded , I usually run a jumper from the engine block to the firewall .
 Above is how I set up the Roadrunner , above all the stock power needs I added 2 electric fuel pumps 1 for each line dedicated to each rail of the EFI , we had 3 electric fans 2 pullers & a pusher , electric water pump , EFI computer , I added a 150 amp alt serpentine driven , & everything worked fine .
 What you need to consider is most of the time the draw will be more like 80 amps as you will not need the electric fans most of the time , especially on the highway , so max draw is nessisary but not most of the time so battery cables should not heat up if they are 4ga

[johns cuda shop]

With all those accessories i would run a aftermarket harness.Something like a American auto wire or a Painless type harness to get away from old wires and the bulk head. Run a voltmeter and get away from the ammeter (volt meter is more accurate at safer) The factory harness was never intended to handle 125 amps or more.When I have a battery in the trunk, I start with a buss bar  (Normally mounted on the inside of the firewall) first. I use 1/0 welding cable to the bus bar to the battery, than 0/1 wire to the starter to the buss bar. (I run all my hi powered accessories from the bus bar that is not run through the ignition switch. I run a 2/0 wire from the battery to the alternator making sure there is a ANL fuse near the battery side of the wire ( in case of runaway voltage ) . Another thing I do is run a 1/0 ground wire from the battery to bellhousing bolt and ground the alternator case on the same frame rail as the battery is mounted on. I would also ground the block to the frame also. 250 amp kinda seems like overkill , as I only have 180 on mine with alot of the same things your running + sum , but again I don't consider myself a expert either 

[HP_Cuda]

Resistance (R) is not your friend.

In light of this use the largest guage wire to run from the trunk to the engine bay.

 

[Mopar Mitch]

I use welder's cable with a twist quick disconnect for the positve.... and ground.   not sure what size... but as it sits between typical wknds, overnight/storage, etc, its always disconnected.

[Travis72]

I used welding cable here as well.  I ran a 1/0 from the battery to the starter through a Ford solenoid switch.  That way that cable is only hot when cranking the engine (it's too much current draw for a fuse).  For the alternator wiring, I ran another cable from the battery to a distribution block like you have and I added a 250 amp ANL fuse back next to the battery.  That way if something ever happened to cut the cable the fuse will blow (which actually happened to me and I was glad I had that fuse!!!!).

Also, if you ever plan on running at a NHRA legal dragstrip they have their own rules for needing a battery disconnect.

Your way of running 1 very large wire to the front simplifies the wiring but then it's not fuse protected.  So if that 3/0 gauge wire got cut and shorted, you could have a major problem.  Type in "electrical battery trunk wiring" in to Google images and you'll find all sorts of wiring diagrams and ideas that people have.

Travis
72 Cuda

[brads70]

Thanks Travis, I did as you suggested and found this post.   http://www.forabodiesonly.com/mopar/showthread.php?t=274097

Even showed how to wire it in with the one wire alternator I bought.!

[brads70]

What about using this coming off the main power wire at the trunk positive cable before it goes up to the front?
http://www.ebay.com/itm/250-AMP-12V-DC-CIRCUIT-BREAKER-REPLACE-FUSE-250A-12VDC-FAST-FREE-USA-SHIPPING-/221131644274

[72bluNblu]

Here's the set up I used in my Duster. Battery is relocated to the trunk with a 4 pole battery cut off next to the battery (Moroso 74102). I used Summit's relocation kit http://www.summitracing.com/parts/sum-g1231-k/overview/ that came with 1 gauge wire and ran that forward to the starter. The starter is then hooked to the relay and a continuous duty relay, I used Moroso's 74107 http://www.summitracing.com/parts/mor-74107/overview/. All of the rest of the loads, including the stock wiring harness, is then run off the CDR. And you can run additional relay's off of the CDR, pulling power from there instead of through the stock wiring harness. That's what I did for my electric fan set up.

This is set up for a standard Mopar 3 wire alternator, but you can simplify it for a single wire pretty easily. The battery cut off kills everything, nothing outside of the trunk should be hot with the cut off thrown. Provided the battery box and hold downs are NHRA, it should pass tech.




Here's where I mounted everything. You can also see my relay's for my Ford Contour dual fan set up on my 26" Champion radiator. Eventually I'll put in a separate relay for my headlights, and eliminate my amp gauge. There's a Sunpro volt gauge (CP8215) that you can remove the guts from and put behind a stock A-body rallye amp gauge, and since the A-body rallye gauge just says alternator and doesn't have any increments you just need to test it with a voltmeter to see where it should be reading. Not sure if that will work for the E-body rallye gauge, but it might. 

[johns cuda shop]

I'm thinking about running a couple of 200 amp circuit breakers in parallel on the battery positive wire between the cut off switch and battery in case there was a short or something from a crash. 

[Strawdawg]

How much current does the starter pull when cranking?

[Chryco Psycho]

unless the rule book specifies switching power I always switch the ground circuits off

[brads70]

How much current does the starter pull when cranking?

[Strawdawg]

It can vary quite a bit depending upon starter size, condition of the starter, voltage available to it, starter temperature, engine compression, initial timing, and so on...Normally, when you first hit the key, the starter will pull a lot more current than it does after it reaches cranking speed.  Sloblo fuses can take a few milliseconds of power in excess of their rating...I never looked to see how circuit breakers work....

If you have 12.5 volts hitting the starter, the current will be less than if the starter is seeing 11 volts when you turn the key...

It's not a simple question.  I have not seen one fused but I understand the reasoning 

[johns cuda shop]

The objective of the circuit breakers is to protect the positive battery cable as it runs from the rear of the car to the front. The idea of the 200amp breakers in parallel is the paralleled pair of breakers open in the event of a short but isn't tripped by the starter . Maybe I am spending too much time thinking over here ,LOL