So, this is a random question, but whats a good length for jumper cables? I have roughly 40ft of pinky-size welding cable set aside to make my jumpers with. How long should I make them? 20ft? 16? I'm contemplating using a little bit of it for something else, but I'm not sure if I should 'waste' it on something else.

 

I'd go with the 20ft. That way if you can't get up close you can still have a chance of connecting the batteries. However welding cable can get quite stiff I believe in cold weather making them very hard to handle in the winter. However they are better than a bad set. Just make sure you get good clamps to put on them.

 

The longer the better. I'd make them as long as possible. Mine are 25 feet. Being able to pull up behind the vehicle and have the cables reach to the front is a huge plus, especially if you need to jump someone (or get a jump yourself) on the side of the road or in a parking lot.

 

Yes, 20-25 ft is good, you can't always pull right up next to the disabled vehicle.

 

If you have welder-wire, the prime consideration I would have is how long to make them in order to reach all the way down the length of YOUR vehicle, and all the way down the length of a stuck vehicle combined. I say that because you can't always get into a good position to jump a battery - especially on the highway.

Do you own an RV? How far is it from the front of your truck - to WHEREVER the batteries are IN THE RV?

You have an excellent opportunity to build a set that can do everything that you could ever need them to do...

But what are your needs?

That should be the determining factor.

 

I've never had a problem getting close to a vehicle. I vote shorter. Why? Long wires are cumbersome which will mean that you'll be less likely to have them with you. Ten feet long is plenty.

Jason

 

make them 100 feet and put them on a spool

 

20 ft is plenty..

If you go longer then you could reduce the effectiveness of the cables.. Especially if your battery is on the weak side..

Better to be as short as possible..

If you ever run into a situation where you can't reach the front of the vehicle just push the car out of it's spot a little so it does reach...

My 2 cents

 

I'm doing the same thing, but my cables are about 12 feet long. I havent gotten the clamp ends yet, as i'm not sure what to use. Do me a favor and post up what you will be using for clamp ends? Thanks.

 

Juper cables are one of those things that once they're in the truck, they'll never leave it (except when being used). I get your point though.

That's actually an interesting idea, but idk if you'd have any juice at the end...

I'm not worried about losing too much current from 20ft of fine-wire welding leads, plus I'm in the process of a 130amp 3G alt swap.

I'll let you know what I'm using as soon as I figure it out. I'm considering some smaller welding ground clamps, but I'm gonna have to look at the local farm store and a few other places to decide for sure.


I'm leaning towards the 20ft set. I was mainly curious about it because I thought I was gonna need a few feet for another project, but I found a short piece at work (metal recycling place) that the boss is letting me have for cheap.

 

go big or go home!

 

One long cable to reach from the Positive to the Positive.
One short cable to ground frame to frame.
40' of cable can give you a a reach of 32' Positive to Positive and a 8' ground cable.

 

I think it would be neat if someone invented a system like the Army vehicles had when I was in 20 years ago. just plug the cable into the receptacle of the dead vehicle and the vehicle with the good battery,and start the engine. No need to raise the hood!!(of course the batteries in the army trucks weren't under the hood,but the idea could still work) Could be almost inconspicuous if located in the right part of the grill.

 

I have two similar sets. One on my service truck, and one on my tow truck. Both are 40' long, and plug into a socket in the grill. I bought them from Snap-On. They make it MUCH SAFER to jump a rig on the highway. I can pull up behind them and not risk being hit by another car.

And the best part? NOBODY can borrow them, so I still have them!

 

All wire has some amount of resistance per unit of length (inversely proportional to the cross-sectional area of the conductor). The longer the wire, the greater the resistance--and the greater the voltage drop. More voltage drop across the wire means that the current through the wire goes up. More current means more heat, more heat means less energy transferred from the good vehicle to the one with the dead battery.

Just recently I sold a truck with a dead battery in it, so every time it was test driven, it had to be jumped. I had it parked at a friend's house (more traffic--more visibility). He couldn't jump it with his cables, because they were small diameter and just didn't allow enough current to flow. I had no problems jumping it with my much larger cables, even with a smaller vehicle and battery on the good end.

The alternator means very little when it comes to jumping a vehicle--the vast majority of the power comes from the good vehicle's battery itself.

The shorter and thicker the cables are, the better.

Jason

P.S. (on edit): I also only hook up the cables battery-to-battery. This takes any loose ground or corrosion in the pathway through the frame(s) out of the equation.