I would only run 2 grounds from your batteries. One to the frame one to the body. I was bored waiting for the woman to get home tonight and decided to do some voltage drops on different systems and different grounding points.

first:
I took my optima out and placed it on my tailgate, I cleaned a spot on my frame rail and hooked up a ground wire. I ran a positive wire to my starter positive and my fuse positive (0 gauge) I disconnected my efi fuse and cranked the vehicle. V-drop positive cable .9v, v-drop ground through frame .4v. This would indicate frame is more conductive.
second:
I did the same thing with the positive cable anly this time I ran a 0 gauge cable for the ground all the way back to the starter, I cleaned the lower bolt and mounted the cable there. I cranked the engine over and had the same .9v drop across the positive. This time the negative drop was also .9v, indicating a higher resistance value.

The ampmeter I used was a vat 40 (old school) and the starter draw cranking was 150 amps. I though this was too low, so I got the winch out but the load moving up the driveway was only 140 amps. I didn't have a extra set of feet for brakes or I would have tried it with a real load.

As for current flow through the frame... 400amps is not really going to cause any radio noise because the current is spread throughout the framerails/body (path of least electron resistance, think of it,is it easier to run in a small tube with 50 people or over a wide flat field?)

when I had my battery in the rear I used 3 grounds off of the battery, one to the cab, one to the frame, and one to the winch(warn requires for warranty) though my winch also goes to ground/frame.

so what am I saying? I'd just ground everything as much as possible.


Oh yea, my current grounds:
Frame to engine 2
frame to body /bed 4
engine to body 3
battery to frame body and winch
you can't have too many but one is not enough, long cables are not really needed.

Brian

DUDE!
Your wife/gal must work a couple cities away... or you are REALLY bored. This one oughta go in the archives.
Great tech info.

[EDIT: is this the Brian who is currently enduring my son, BTW??? He really really looks up to you, FYI. He's having a great learning experience.]

I plan on mimicking Roger's setup electrically in any event. That means, I will run TWO positives up front to the engine compartment/winch, keeping the two circuits separate so that the aux batt runs the winch and accessories, the primary batt runs the engine etc., and a solenoid (when active) parallels the two circuits (allowing the charge circuit to charge both batts when ignition is on, but isolating the batts when its off, but both batts are available for their respective duties).

This puts only the charge current and perhaps some equalization current through the solenoid, and in a large draw situation will allow more current but never more than 1/2 or so of total depending on relative battery condition and the current will pass through each battery's positive instead of just one positive cable.

The other alternative, putting the solenoid in the rear with the batteries (actually does not matter *where* the solenoid is, the key is one, or two, cables running forward of course), would route all aux current through the solenoid in the event of a large draw (or any draw, though still probably not more than 1/2 or so) and provide only one positive in the engine bay via one positive cable. Because of this, the main batt would be the only available one with the ignition off under this approach.

Good advice on armoring the positives. I will have to compare some good split loom armor vs. heater hose. Not sure I want to go with the fusible link, but I might.

Had a conversation with the good folks at Wrangler NW Power Products. He had absolutely no issue with using the frame as a ground even with a winch, he's done so many times with many different vehicle configurations. He did strongly suggest beefing up the ground straps from engine to frame, and body to frame, good advice under any circumstances.

He also said their hammer-style crimper is all they used to use on field calls, and makes quite reliable connections. So its in the mail, part # 38-101.

Thanks for the discussion, guys! Many counselors make for a wise choice. Or confusion. Not in this case.

I used the hammer crimp tool as well, it works pretty good, maybe not as pretty as the fancy crimper, but once you apply the adhesive filled heat shrink tubing, its a bulletproof connection. Count on spending a good deal of time making up the cables, I forget how much time I spent but it was like 30 minutes to make up 2 ends of a cable by the time you cut it to length (I had a large enough wire cutter), strip the insulation, crimp, heat shrink and insert the lugs into the connectors. And as Norm Abrams says, "measure twice, cut once!".

I remember spending 6 months one week making up terminations on a low voltage control system. Takes a BUNCH more time than you think it should. Takes several times longer than the salesman sold to the customer, too. <img src="/forums/images/graemlins/notooth.gif" alt="" /> The carpal tunnel syndrome? Priceless. <img src="/forums/images/graemlins/shocked.gif" alt="" />

FWIW, I found the tool even cheaper, and other parts cheaper, from a local Colorado supplier, for you CO fellers.

800-608-5595
www.columbineautoproducts.com

Longmont. One day UPS service to my house, via ground rates.

Working with this heavy cable is what is hard and tiring. No real carpal tunnel risk, its more likely to get a thumb smashed by a stray hammer blow. I had to use a rubber mallet to get my wire cutters to go through the stuff, no way you can squeeze them hard enough by hand to work. Then the stripping is tricky, its heavy, tough insulation, but you need to be careful not to cut into the fine copper strands underneath. And with the cumbersome length of cable, you don't just twirl it around in your fingers. I made up quite a bit of cable with mine (went through a good part of the 100' I bought), making jumper cables, extensions, etc. I can unplug the winch and plug in a set of jumper cables without opening the hood and also have a plug at the back of the truck for the same purpose.

I like to call it carpal thumb... BTDT <img src="/forums/images/graemlins/lol.gif" alt="" />

similar thread on dual bat's over on the Pirate BBS

I didn't see a pic on the Wrangler site, but I think thats the crimper I have. I have a Harbor Freight 6-ton press - the kind made with a hydraulic jack. That works pretty well. No mashed thumbs and I think it's probably a little easier to keep the wire in the lug, lined up the right way etc. although there are still times when an extra hand would be handy. One hint, if you're running short cables, make sure you orient the lugs the right way. You can get away with twisting a small wire because a crimp lug isn't oriented right axially on the wire, but it doesn't work so well with a short lenght of battery cable. If possible, I crimp one end, temporarily route the cable, cut to length and trim insulation and put on second lug. Then I know how it needs to be oriented after any bends in the cable are made. Of course, I still seem to end up with it not exactly right on the length though!