Grounding question for my rear battery setup

[haygood at myway.com (Brian Haygood)]

I ran a "+" cable from the battery straight to the starter.  I wouldn't recommend running the big cable to a distribution block.  Run it directly to the starter.  The alternator wire already comes off the same lug on the starter, and the two red wires that run up toward the firewall can be extended to reach the starter - barely (on a 16v at least).  If you want a distribution block because you are adding more accessory power wires (i.e. relayed headlights, stereo, etc.), then run a moderately sized wire from the starter up to the distribution block.  That way your starter and alternator are connected as directly as possible to the battery.  



I ran a ground wire from the battery to a rear bumper bracket bolt.  The results of the new battery cables was that my starter spun super fast - almost sounded like a sport bike starter or something.  I don't see any need to run a ground cable from the battery directly to anywhere.  The cross-section of the sheetmetal is way more than any cable you would use - copper or not.  If you need better grounding for something, connect things to the car body better.  I wouldn't bother with a cable back to the battery.  



The circuit breaker or cut-off switch should be on the "+" side of the battery, I think.  That may just be convention, but fuses and breakers are pretty much always put in the power side of a circuit.  I'm too tired now to ponder whether it would ever actually matter, but some EE's can answer that anyway.  









 --- On Mon 03/13, GGehrke < ggehrke@gmail.com > wrote:

From: GGehrke [mailto: ggehrke@gmail.com]

To: Scirocco-l@scirocco.org

Date: Mon, 13 Mar 2006 11:18:26 -0500

Subject: Grounding question for my rear battery setup



So I'm about to finish planning my electrical system and start<br>ordering parts and have a question about the grounding system...<br><br>I'm putting the battery in the rear and running a beef power cable up<br>front to a distribution block where the battery used to sit.  That<br>should give me a good strong positive terminal for the starter,<br>alternator, headlights, etc.  I'm debating, though, whether I need to<br>run a beefy ground cable along with it.  I'm planning to use a really<br>heavy cable or grounding strap to attach the battery negative directly<br>to the car body where I mount it.  Would it be sufficient, then, to<br>put a distribution block up front (and, for example, under the dash,<br>or wherever else) and ground it with a heavy cable?  I'm thinking use<br>the car itself to make a good connection rather than have to run more<br>heavy gauge wire all over the place.  I figure then I'd branch off the<br>front distribution block to ground the engine, etc, and put 
a distro<br>block under the dash to ground any of my under dash stuff.<br><br>I'm thinking as a bit of a compromise I might just ground the battery<br>really well and run lighter gauge (8, probably) wire up to a distro<br>block under the dash and then one up at the very front where the batt<br>used to be, plus ground those blocks to the chassis.<br><br>Any thoughts from the list?<br><br>I wish I had the luxury of actually checking it out to see what kind<br>of voltage drops I'd get and really compare the two theories, but I<br>have neither the time nor regular access to the car to 'experiment'. <br>:(<br><br>Oh, and another crucial planning question - I am putting a master<br>cutoff switch on the battery as well.  Should I put it in the positive<br>or negative line?  Usually when I see bentley instructions they say to<br>"remove the negative terminal" so that seems like a good bet, but I'm<br>not really sure it would make the least bit of 
difference...<br><br>-Grant-<br><br>_______________________________________________<br>Scirocco-l mailing list<br>Scirocco-l@scirocco.org<br>http://neubayern.net/mailman/listinfo/scirocco-l<br>

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