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Battery in trunk wiring?
https://slantsix.org/forum/viewtopic.php?t=21223		 Page 2 of 2
Author:  slantzilla [ Fri Dec 29, 2006 4:07 am ]
Post subject: 
ANy approved box will be sealed and vented. Even a sealed battery must be in an approved box or the trunk bulkheaded. Your parts vendor will be able to steer you toward an approved box.

Your local tech guy can and may approve whatever he wants, but that may not be valid if you go to another track elsewhere. :shock:
Author:  kesteb [ Sat Dec 30, 2006 10:41 am ]
Post subject: 
I understand the kill switch, but why don't newer cars also need one. Most hoods are locked or have internal releases now. It seems to me that rule is a little outdated.
Author:  AnotherSix [ Sat Dec 30, 2006 6:16 pm ]
Post subject: 
On normal cars the engine compartment is open on the bottom, it is also the only place the main battery cables run. The cables are not near the fuel tank or the cabin. Short of a fuel leak, there is not much to burn in there. It's the 10 plus feet of fat cable from a rear mount shorting, turning red and cutting or burning thru things that is the safety issue. A normal car with a standard cable will likely burn or melt thru the thinner stock positive cable if it gets shorted without lighting up the whole car. Having owned a car with a trunk mount battery I would not do it again except on a race car. I have thought about using a smaller odyssey battery and mounting it farther back and lower in the engine compartment, just to help handling. They are expensive but it probably costs less than a rear mount without the problems and maybe about half the weight transfer benefit. They last a long time too.
Author:  sick6 [ Wed Jan 03, 2007 12:09 pm ]
Post subject: 
so is anyone on here currently running a rear mounted set up?

I'd like to see a couple of pics if possible to let me know what I am in for.
Author:  KBB_of_TMC [ Fri Jan 05, 2007 10:04 am ]
Post subject:  cable questions
We're also planning on trunk mounted batteries for the TMC '68 Fury (http://www.tidewatermoparclub.com/furry07.html), and I've found it hard to find **inexpensive** heavy cable. Waytek and JCWhitney seem best, but does anyone know of a less expensive, possibly surplus, source for 25' of 1/0? The (copper) cost at Waytek as doubled since their catalog was printed in Oct06, and a minimum length of 100' has made it cost prohibitive.

The spec's I've found suggest that the starter will draw ~200A normally and ~400A at lock. We're not planning on a kill switch, and we're planning on 2 gel-cell 12 batteries in the trunk.

I'd planned on 1/0 for the starter, but estimate that we can just squeak by with #2. I also estimated that there is enough steel in the beefed-up subframe to allow us to use it for return path along with a heavy block-to-subframe jumper and large stainless bolts tapped into the frame.

While I know heavier is better, we're trying to minimize weight and cost. Does this scheme jive with most people's experience, or are we likely to run into problems?
Author:  slantzilla [ Fri Jan 05, 2007 11:53 am ]
Post subject: 
With a battery in the trunk I would definitely have a kill switch, just for the safety of it. :shock:

Welding supply store may be a cheaper alternative on cable, or maybe some used cables from a machine shop?
Author:  KBB_of_TMC [ Fri Jan 05, 2007 7:25 pm ]
Post subject: 
Thanks, but I've found welding cable to be much more expensive than battery cable and have had no luck locally finding used stuff cheap. I suspect that due to the high price of copper most such cable is immediately recycled. Actually, a local guy was caught stealing similar cable from my place of employment to sell to recyclers last month, so I wouldn't even think of asking them for scrap.

I'm planning on using fusible links on the batteries (except for the starter run) and no kill switch, unless somebody donates 2 good ones, and high quality feedthroughs from Waytek. The channel containing the cables will have a steel cover to protect it from damage. A 100A breaker protects the isolation diodes between batteries, and an inexpensive 100A continous/500A momentary switch allows for bypassing the isolator.

The plan calls for a ~100A alternator of some kind yet to be determined, and I plan to keep the stock ammeter, but rescale it using an external shunt (avoiding the need for an active shunt).

This is a charity car, so many of the parts are paid for out of our pockets, so we try to build a great car as inexpensively as possible.
Author:  Pierre [ Fri Jan 05, 2007 9:30 pm ]
Post subject: 
Try a local car audio shop (not a bestbuy/circuitcity type, but real stereo/alarm shops) Most manufacturers make ultra flexible (several hundred, sometimes thousand strands for larger awg) wire. The generic brands can be had cheap, and some are plated for extra corrosion resistance.
Author:  dakight [ Sat Jan 06, 2007 3:58 am ]
Post subject: 
Rhode Island Wire - http://www.riwire.com/ - lists 1/0 at $5.51/ft for less than 25 ft. 25 - 99 ft is $4.51. That's not cheap, but not impossible either.
Author:  Pierre [ Sat Jan 06, 2007 8:55 am ]
Post subject: 
Whatever you do call and ask for a sample - most of the time they are free, but even if you have to pay its worth it before making a big investment. Cheaper cable oftentimes has tough insulation or a low number of strands making it hard to route and terminate.
Author:  AnotherSix [ Sat Jan 06, 2007 10:14 pm ]
Post subject: 
Yeah if it is normal electrical cable for heavy service it is very stiff and the strands are real heavy, something like 14 ga. each. It's much cheaper that welding cable but will not really work. Even the insulation is stiff.
Author:  KBB_of_TMC [ Sun Jan 07, 2007 3:14 pm ]
Post subject: 
Thanks; I've found many places that have 1/0 ~ $5/ft & #2 ~ $2/ft, but when you need a lot of cable that adds up fast. All the stereo places I've tried were ~2X more expensive. The insulation on the big audio cables seems less robust that battery cables, but I've not tested them. Is the insulation as soft as it seems?

An isolated starting-only and another primary battery & isolator in the trunk + keeping the stock ammeter means 2X as much cable as the simpliest setup; throw in a line for a ~kW trunk mounted stereo and we're up to 3X. My origional plan called for 25' 1/0 and 75' #2, and that was just too expensive. I'm now planning on 100' #2 and maybe doubling up the starter run.

Thanks for suggesting heavy cable intended for commercial construction - I don't need a lot of flexibility once I get it in, and plan to use big stud-type feedthroughs at the filewall.

Sometimes, aluminum wire is used for high currents in buildings - anyone tried that in an automotive environment? I know it can be a pain due to corrosion, but has anyone tried it?
Author:  Pierre [ Sun Jan 07, 2007 3:51 pm ]
Post subject: 
Insulation doesn't necessarily have to be hard to be durable. If your that worried about it you can run it in a loom or some other covering. Haven't ran into any insulation issues before. Theres millions of feet of it in use...

www.genuinedealz.com shows 1/0 for $4.15/foot when by the foot for the type III. 2awg is 1.95/ft type II and 2.60/ft for type III. I've bought the typeIII stuff from genuinedealz and its excellent stuff. Again, this is marine wire, its tinned not bare copper. Its a bit cheaper if you buy it by the roll.

Wire maybe the least often thing replaced on the car - don't skimp here. 2awg and 1/0 is going to be expensive, theres a significantly more copper in it then the double-digit gauge sizes.
Author:  Pierre [ Sun Jan 07, 2007 4:02 pm ]
Post subject: 
Also just noticed genuinedealz has 2/0 type II for $3.81/ft! (as opposed to the type III thats 5.21/ft) Yikes, that is cheap, but typeII is stiffer then type III it has less strands - stiff wire is a pita to install. Waste $20 to order small lengths to samples if you have to because you'll kick yourself for spending that much on wire you haven't seen then you realize takes a pipe bender to get it to curve.

Terminals will nickel and dime you to death too.

Only building wire I had experience with is copper, and its one solid strand all the way through. Bend it back and forth a few times and it snaps, not a good idea for car stuffs.
Author:  dakight [ Sun Jan 07, 2007 5:20 pm ]
Post subject: 
I would stay away from aluminum wire. It has more resistance per foot and is an order of magnitude more difficult to work with. You can't solder it and crimp connections are subject to corrosion and heating if they get even a little loose. There's a reason it is no longer used in residential wiring.
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