Cutting and stripping battery cables

[CalTran]

Originally Posted by ratdude747

But if you guys (and gals) of all people make it work, then I really don't know what to say. I guess "do what works for you, and to each their own?"

Though for the record, Al is magical enough he could probably correctly solder a battery cable using nothing more than a single match and the lead[1] from a pencil.

Team 2410 has a similar pair to the Harbor Freight 10" cable cutters, though ours might be a more generic brand. In the past to solder the connections, we used a butane torch.

[1] - I know they're graphite.

[Mike9966]

Hi all,
Just a thought on the wattage of the iron.
We use an iron that is only 35-40 watts, but the tip is MASSIVE, like 1/2" in diameter, with a 5/16" chisel point.
This allows it to hold heat so it's not so much the wattage of the iron heating your joint, but the heat transfer from the big tip to your connector.

Remember to clean the tip and tin it, and work fast so as not to melt all the insulation off the wire as you are soldering.

Works great!

Good luck, and have fun playing the game,

Mike

[DonRotolo]

Originally Posted by ratdude747

Side note- I've always heard that if you nick off one or two strands (or a few for finer stranded wire, like 6 gauge battery cables) that it's OK.

In most cases, it is not OK. The connection is already a poor conductor (relative to the rest of the wire), and adding resistance makes it worse.

It will be measurably warmer at the connection when a wire is nicked, and even mode so when strands are missing. (We're talking 6 AWG battery cables here)

[Road Rash]

Originally Posted by Al Skierkiewicz

Do not allow the mechanical team to find them or they will be toast in a minute.

Thanks as I would've never thought of this. I might just suggest we organize our tools that all electrical tools remain separate from the mechanical team.

[D.gimon]

Originally Posted by philso

At work and for FRC, I use a utility knife and cut about 2/3 to 3/4 of the way through the insulation, all the way around. This is to avoid cutting the copper strands (we mainly use the high-strand count stuff at work). I then bend and flex the cable at the cut, causing the remaining insulation to rip. The unwanted insulation can then be twisted and pulled off.

I was hoping someone out there would suggest that method philso. That's the way I do it.

Dan

[Al Skierkiewicz]

Originally Posted by ratdude747

My "2 strands" rule was for wires with a larger number of strands. Like 10 or more. Also note that the copper strands do connect internally (inside the wire), so the justification was that it's only missing for a short part, not the whole wire.

So, the current carrying ability of the wire is specifically related to the cross sectional area of the wire, measured in circular mils. The strands are bare copper and do connect internally to each other but reducing circular mils at any point reduces the entire wire to the smaller gauge and therefor higher resistance.
I showed several teams over the weekend the method I use for stripping large gauge wire without damaging the wire. Using a sharp knife or box cutters, push the blade onto the insulation while the wire is laying flat on a table. Then roll the wire. This will allow the blade to travel through the insulation without cutting any strands. Do not move the blade, let the rolling action move it around the wire. When you have rolled all the way around the wire, then bend the wire at the cut and you should see copper. Continue to bend all around the wire. The insulation may be pulled off at this point with your fingers. If the insulation is really tight, take the blade and place it almost parallel to the wire and skim some of the insulation that you want to remove. Think like you are filleting a fish. As you remove the thicker part of the insulation, it will be easy to remove with your fingers. This method also does not disturb the lay of the strands, making it easier to insert in a terminal.
BTW, if you are using screw terminals like these...https://www.grainger.com/product/BLA...onnector-3LT05
You must insert enough wire so that the copper is visible for at least 1/8" on the opposite side of the contact from where the wire enters. When you tighten the screw, the end of the wire showing will spread out to help assist with wire retention. If you do not do this, when you tighten the screw, it will simply push the wire out of the terminal and that leads to failure. I really prefer these types...https://www.grainger.com/product/THO...pression-6MFT9 You can crimp them in a vise if you do not have the right crimper. To do this, insert the wire into the terminal. Then place the wire and terminal in the corner of the jaws at a 45 degrees for only half of the terminal. Tighten the vise until you can't any more. Remove the terminal and rotate 180 degress and crimp the other side. When done you should have a nice "X" pattern on the terminal when complete. Then give it a real tug test to be sure it is tight. We follow up with solder at this point.

[sanddrag]

This crimper works quite well on the big stuff for the reasonable price.