I'm building a C cab and due to space restrictions, I have to mount the battery towards the back. Will #2 AWG cable be what I would need to use for a 10' run. Thanks.
You could probably get away with it with a smaller engine that cranks easily. If you give us a bit more info, like how long the cables will be (both positive and negative), as well as the engine type and modifications to it, maybe we could guess better
In my 51 shoebox with a 305, I put the battery in the trunk, ran ONE welding cable( auto shops call it that) up the the starter, the ground cable of course, was very short as it just attached to the frame under the battery area..
I would personally not use #2 gauge wire- It might cover you, but the bigger the gauge the better. I recall seeing a guy that made his battery cables for a car out of old jumper cables (If I recall they were #2 gauge)... It was a pretty long run, and suffice to say the cable didn't last long trying to crank the 327. I'd do with 1/0 or 2/0 (when you ask for it, say 1 ought or 2 ought). My '33 stock car was pretty tricky to find a spot for a battery, and I ended up using an Odyssey PC680. I'd say there's at least 10 feet of cable, and I ran it with 1/0. I have no trouble spinning over the starter in my 283.
It really depends on what type of cable you run. Not all cable is rated the same ampacity, and the finer the strands, the more ampacity it holds. A #2 is rated 100 amps in it's lowest rating, but in fine strand machine tool, or welding cable the ampacity is double at 200 amps. I'd go with #2 if you buy the welding cable, or machine tool cable, but not the coarse strand cable.
I used welding cable on my 36 p/u with battery under the bed. Positive length to the starter, and a short negative to the frame near the battery. Don't forget a ground cable to a CLEAN (no paint) point on the block (I used a trans to engine bolt) from the frame up front,and a ground cable to the body if steel,or a ground buss bar if glass body
The local battery shop recommended 2/0. Partially because of the small price difference between 1 and 2/0. DC doesn't travel very well and needs large conductors and good mechanical connections. I used 1/0 on my remote battery, but I haven't fired the engine yet....... K
HA that's funny I read your post then thought Hey my dad is building a C cab and he is in Brandon too.....Hi dad!
I ran my 51 ford for 8 years without one problem.....it was on the the second battery after the 5th year...the car always started like the battery was right beside the starter....when I build one, I usually drive it trouble free for years and years....
I used #2 copper for the trunk mounted battery in the 37 Buick, left over from a 100 amp subpanel installation in my shop. Works great, spins the engine over easily at all temps. BIggest issue IMO is to have a good ground. I run the hot line from the battery to the starter, ground from the block to the frame up front and a ground from the frame to the battery in the back. Frame is also grounded to the body but with a smaller factory style ground strap, everything else is #2 stranded copper.
I'll try to answer everyone's questions here. Positive cable will be ten feet long. Negatives will only be a foot or so, just to ground to the frame and to ground the motor also. Motor is a stock 283, no mods. Also, no ac, will only have radio, lights, starter draw, gauges and fuel pump. Starter will be the heaviest draw. The cable I was looking at was #2 AWG welding cable type k. I also looked at the 1/0 and the 2/0 but couldn't find out the difference between them and the #2 AWG. I believe the AWG is a little smaller but don't know how much. Anyone know what the size difference is?? Appreciate the help. Bob ps, Hi Steve.
Size difference? 2/0 will about twice the size of #2, 1/0 roughly midway between. The starter draw is the draw you need to worry about. There's a number of factors to consider; will your motor start easily and quickly? With a small motor like a 283 (I assume a mild motor; no high-compression here) a #2 will probably be adequate. But with a larger motor, low battery, extended starting time, or worn starter the draw could be more than the #2 can handle. Small wire with high amp motor loads heats up; as it heats, it's ability to deliver voltage degrades rather quickly, causing the motor amps to climb yet more, causing more heat, so forth and so on... The 2/0 will handle just about anything you throw at it, the #2 may not be able....
Around me it is hard to find 1/0. For batteries located in the engine compartment I usually use #2 welding cable. If it is a long run then I switch to 2/0 welding cable. The welding cable is a lot more flexible so it is easier to route. If you are worried about size due to space considerations you could find the draw for your starting circuit and do the math...there are online calculators I've seen. I have 25' of 2/0 welding cable in the shop I bought off eBay for a fraction of what Napa/Carquest wanted that I'm using on a tractor. The OD including insulation is right around .060"
Any decent welding shop can get quality welding cables in any gauge. I made some using 2/0 that would start a semi. For long runs (anything over about six feet, IMO), they are the only thing I'd consider.
My wife has an off-topic little car that has a factory trunk mounted battery...and the cables look like #6 gauge wire. Stock, from the factory. And it starts every time. If you can afford 2/0 wire, go for it. If not, you might be able to get away with less.
Guess I'll be going with the 2/0 welding cable, thanks for all the help. Here's a pic. Couldn't figure out how to upload more than one.
On my T-bucket I used 1/0 welding cable. 6 years and no problems. I saw somewhere to not use welding cable forget why but it worked for me. Bill
I would go with 1/0 welding cable, there is a huge difference between #2 and 1/0 cable. You won't regret it. You can get any size cable and cable ends from McMaster-Carr.
Sorry, but this is just wrong info. Circular mils of #2, vs. 1/0 and 2/0 are not double and halfway between. #2 has a diameter of 258 mil #1/0 diameter is 325 mil #2/0 diameter is 365 mil So as you can see 1/0 is about 20% larger than #2 and 2/0 is about 10% larger than 1/0, and about 35% larger than #2.
I was only giving very approximate sizes; the CM numbers are only for the wire, when you add the insulation to them that changes the overall size. And the larger sizes generally get somewhat thicker insulation.
...and current carrying ability is proportional to cross section area, which is proportional to diameter squared. (sorry for the engineering words)
Current carrying capacity is directly related to circular mils, but also to density. A solid wire carries the most ampacity, but is a poor choice for automotive or vibration. A 12-16 strand conductor is nowhere near the current capacity of a 100 strand in the same size. Insulation also affects current rating, as it relates to temperatures, but although insulation does increase in thickness with size, there's very little difference in insulation between the three sizes referred to. What will really affect insulation thickness is temperature rating of the insulation. Lots of other things effect current carrying capability, or rating, but not relative to automotive uses really.
As long as the two ends are attached to clean, continuous metal you usually won't need the ground cable ran along with the positive. You do want to use a big enough ground strap from the engine to whatever you bonded the negative to in the back (frame or body), then a smaller one if needed for any other bonding. I scrapped out a '86 Jag XJS recently, and a few things I salvaged was the battery cables (factory trunk-mounted battery) and a couple of bulkhead fittings. The fittings are pretty cool, bolt them through a hole in the firewall and they're insulated from ground, and the best part is there's a #10 threaded stud inside the car for power pick-up. The 'main' cable attaches to this, then you use a short jumper to the starter. The cables are about 2/0, and while finer strand than building wire, not as fine as welding cable. but nice cable nonetheless; sealed at both ends, with battery terminals on one end.
Yep, I run one good cable to the frame in back, and one from frame to block in front. Good bare connection at both ends and never a problem. same setup on my car for three years now, and never failed to crank right up.