I am rewording my 31 coupe headlights, tail lights , starter, dash radio, msd. Should I use number 2 or number 4 size wire for power to starter? Posted using the Full Custom H.A.M.B. App!
A quick read suggests the larger diameter with greater capacity, esp. in a longer run from the batt. Might look at some larger older OEM examples. Fine strand and high quality are worth the investment.
should the ground wire match the power wire? YES, think of it like this, all the current that comes from the battery must go back to the battery, right?
Thanks 46, to many people at stores telling me different stuff. been told number 2 welding cable would be good, anyone have any recommendations on weather to use it or not.
Without a lot more info, we'd be guessing. Since we're not paying for the cables, we'll probably recommend something bigger than you need. What engine? how long are the cables? Should we ***ume you're running a 12v system? Little details like these can make a big difference
How long is the cable run? Voltage drop in a given wire size goes up with wire length and load, so the longer the run, the larger the wire needed to keep drop down to acceptable levels. Personally, I wouldn't use smaller than #2 for a starter cable in any case, over 6 feet I'd go up to #1, over 10 feet up to 1/0.
Number 2 welding cable should work fine. A normal battery cable that you can buy should also work fine, and you won't have to mess with putting ends on it. Route it carefully so it won't get rubbed thru the insulation.
I, personally wouldn't recommend it. Welding cable usually doesn't have the strand count or flexibility of dedicated grounding cable nor is it made for the job you want it to do -seen many welders riding down the highways at 60 mph? For the cost relative to the rest of your electrical system, get the real stuff-and make sure it's copper-nothing else carries the same amount of current as well. Here's a place to start, and I like Ron Francis for good electrical bits. http://www.ceautoelectricsupply.com/batterycable.html
Consider checking out marine supply places. If their wire can withstand a wet, harsh environment as found on a boat, it's great for automotive use. And their battery cable wire has a high strand count for flexibility, and each strand is tinned (coated with solder) to resist corrosion. Welding cable would certainly work, but all of it I've seen is plain copper wire, so it would be prone to corrosion. I have no affiliation with this company, but they seem to have a good selection of items, and their wire is "Made in USA", not Chinese ****. The website also has some good info on wire sizing. Wayne www.bestboatwire.com
While 'marine rated' wiring is generally good stuff, the premium in price really isn't justified for automotive use and many times there's little difference. The difference between tinned and bare copper strands will make little difference if the terminations are properly sealed, so unless you have some extreme environmental conditions, it shouldn't matter. If you do have that, using a fully sealed connector like Deutsch or the GM weather pack would be a better choice. Welding cable is about the most flexible cable commonly available, so 5window's dislike of it is puzzling...
I ditto 1/0 welding cable, Carry both sides to the front if you are moving the battery location (learned that on a race car), you can also ground the ch***is at the battery, make sure you have a good jumper to the engine block from the body, and the ch***is. It is flexible, high strand count, also easily purchased by the foot from a welding shop. If you want, have terminal ends crimped on it there. #2 cable will heat up if you have a hard cranking motor, my "old electricians" reference said it was good for 100 amps ac with adequate cooling. My winch motor for my trailer drew 450 amps and would heat it up till it smoked. Kinda like them cheap booster cables when you strip them you find #10 wire. They will carry a larger load, but not continuous duty cycle. THE eggheads say electricity runs on the outside of the individual wires, conductors.. so the flat braided wire grounding cables seen on old cars were "great". A good welding cable has wires a little finer than 22 ga.. (larger than hair) I used to tell people to "do it their way" and I'd wave later as I p***ed on by. THE old codgers that built them old cars did have some common sense.
I'm not sure about all the differences between then different cables, but I've been using # 2 welding cable on my last three cars. My 40 P.U. I had for 12 years and my roadster I have now is on the road for almost 4 years. Zero problems and the cables never get warm. I even found it in red at a welders supply house.
http://custombatterycables.com/info_pages/wire_types.htm Just for clarity. Flexible,ok, but if you do a Google search, you'll find lots if instances where welding cable dry rotted, or broke down in oil or some other failure. I like adapting stuff to use on my car- but not when it's going to be where I can't see it, and failure could be calamitous. To each, his own.
When in doubt go larger...within reason! We bought an old 31 Roadster once as a raffle car. It would be perfect today for this forum. Oldsmobile drive train with the battery in the trunk. Hard to start when hot. We put welding cable on it and the problem disappeared. Welding shops carry 2 different size cables. You want the "whip" cable. Smaller than the cable that was strung all over the job site and easier on the welder to manipulate than the larger heavier cable. Measure what you want accurately and they will cut it to your exact length and install lug ends in a press so you can take it home and install it. You won't find any 12V pre made 6' long cables in your auto supply store. If you ever fought a hard to start while warm problem, you will opt for good old welding cable to start with. Yeah pre made cables are cheaper but holding up your buddies at the gas station can be very embarr***ing. I thought I was smart and welded a 3/8" bolt to the frame just for the ground cable. No hard to start problems for me...wrong. I fought it for a year until I moved the ground cable from the frame to the tail shaft housing on the 350 trans (battery under the seat) Problem solved. I guess a jumper cable might have fixed it but that's just another connection to get dirty and cause resistance. We can't see the path of the electrons so we cannot be sure it won't have a bad connection.
Battery in trunk means you'll want top shelf (+, - cable) quality. I spent time puzzled with poor starting, until I ran both cables forward and to the starter/bellhousing. Prior to, the voltage would drop to 8.9 V. Sometimes she'd start, sometimes not.
Many, many cars are running with welding cable. It's common to use good used cable and cover the insulation with friction tape or rubber hose. For 12 volts #1 or #2 should be fine to go 6' for a typical engine. If 6 volts, then go for #o or #oo guage. Best to put both frame straps on one rail, unless you've welded the frame. Those rivets won't conduct well on a riveted frame, once they get old. Ground strap can be to the frame, if the frame has a ground strap to the engine and one to the body. They can be very short, but the connections must be very good. Also, I would not just crimp the ends. I'd sweat them on with rosin core solder, making sure the ends of the cable and the lugs were tinned well first. A crimp-on connection is just a hole waiting to collect dirt and water.
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