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riven1950's avatar
riven1950
Explorer
Jun 09, 2020

crimping battery lug

Ok, this is on my boat but very well could be an RV question so I hope it is appropriate.

While replacing a pump I noticed one of the positive battery cables going into the battery selector switch appears loose in the lug.

Problem is there is very little room to work and removing the entire cable is a lot of work.

Trying to figure out what hand tool I could use to press the lug back on the cable tightly.

I looked online and see people using a hammer and screwdriver and some sort of press. I don't have a crimping press and not sure it would fir in the small area I am working. I have a hammer and screwdriver but not very helpful where I'm working either.

Any ideas?
Seeking Advice
  • byronlj's avatar
    byronlj
    Explorer
    Jun 10, 2020
    I have been building battery cables for decades using solder. You only need a handheld propane torch to accomplish the task. Auto parts stores even sell lugs that contain the solder or have a solder puck. Lots of videos on this.
  • Super_Dave's avatar
    Super_Dave
    Explorer
    Jun 10, 2020
    Lynnmor wrote:
    Super_Dave wrote:
    You can buy another cable with double lugs for about $10 on Amazon. How hard can it be to take the nut off the battery and the nut off the back of the perko switch?


    We don't know how the cable is routed, wanna replace the cable on my Ford pickup for ten bucks?


    Boats with dual batteries and a selector switch typically have the switch in the battery compartment, no more than a 3' cable. If I misunderstood the problem, my bad.
  • riven1950's avatar
    riven1950
    Explorer
    Jun 10, 2020
    Super Dave wrote:

    Boats with dual batteries and a selector switch typically have the switch in the battery compartment, no more than a 3' cable. If I misunderstood the problem, my bad.


    No Problem. I did replace the short wire which was corroded but not loose in the lug. Of course it is only 15" long. The other wire is about 6 feet and snakes to the other side of the boat. 20 year old boat and access to pumps, wiring, etc. is a pain in the a--.
  • Veebyes's avatar
    Veebyes
    Explorer II
    Jun 11, 2020
    I love it when builders make things just barely good enough.

    The long way might be the easiest way overall. Fish a new wire, with length to spare through & do it the way it should have been in the first place.
  • dodge_guy's avatar
    dodge_guy
    Explorer II
    Jun 11, 2020
    wa8yxm wrote:
    byronlj wrote:
    Take the lug off, clean it, and solder it back on using flux.


    Sounds easy.. But do you have any idea how big a soldering iron you need to handle Battery cable (4ga or bigger) wire.

    A welding torch would be my first choice.. Though I might do it with a good propane torch.

    The crimping tool someone up-thread suggested.. From the photos it looks like it does a very professional job. Some of those hand tools I use (on smaller wires) the crimp looks to my practiced eye to be better than some factory crimps.

    That is one of 'em.


    You can buy small butane torches. Not a butane soldering gun but an actual torch that uses butane. I use that for soldering and heat shrink. It’s small enough to fit in confined areas. Puts out enough heat to heat up a copper lug but not enough to melt anything around it!
  • Grit_dog's avatar
    Grit_dog
    Navigator
    Jun 11, 2020
    wa8yxm wrote:


    A welding torch would be my first choice.. Though I might do it with a good propane torch.

    .


    What?? LOL.
    I could probably solder it with a bic lighter if I had to. A run of the mill plumbing torch or mini butane torch will get it.
    You'd have to try hard not to melt everything with an oxy acetylene torch even with a #0 or #1 tip.
  • Grit_dog's avatar
    Grit_dog
    Navigator
    Jun 11, 2020
    dodge guy wrote:

    You can buy small butane torches. Not a butane soldering gun but an actual torch that uses butane. I use that for soldering and heat shrink. It’s small enough to fit in confined areas. Puts out enough heat to heat up a copper lug but not enough to melt anything around it!


    Yup. I don't use it very often, but it is handy for the right things. Like....soldering and I've unfroze a couple door locks with it.
  • CavemanCharlie's avatar
    CavemanCharlie
    Explorer III
    Jun 12, 2020
    I would duct tape it.... Just kidding. Glad you found a solution to your problem.

    I was going to suggest using a solid piece of metal undernieth of it and then use a hammer and a center punch to dimple the out side of it in a lot of places. By doing this you are also crushing the outside at the same time. The dimples give the metal a place to shrink and then the whole thing squeezes together tighter.
  • ppine's avatar
    ppine
    Explorer II
    Jun 12, 2020
    crimping tool made for the size of your cable.
    alternatively, you can remove the old lug and add a new one that has a set screw.
  • JRscooby's avatar
    JRscooby
    Explorer II
    Jun 12, 2020
    byronlj wrote:
    I have been building battery cables for decades using solder. You only need a handheld propane torch to accomplish the task. Auto parts stores even sell lugs that contain the solder or have a solder puck. Lots of videos on this.


    On more than 1 occasion I have found ends soldered to cable, and the end comes off. I think a bad connection at the post heats the terminal, loose some solder.Clean the post, but now some resistance at the solder joint.
    This is on truck starting batteries, my never be issue for low amp loads.

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