welding cable

so is it generally agreed that 4/0 welding cable copper multi strand is the best battery


  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: welding cable

    Best? Best is what will work for a particular install that doesn't cost an arm and a leg.
    Fine-stranded wire needs really good, tight crimping.

    My cables, btw, are 2/0 multi-strand but not the fine strand welding stuff. Works fine.
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    Re: welding cable

    The best is when you conform to requirements!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
    E-mail [email protected]

  • samuelsamuel Solar Expert Posts: 80 ✭✭✭✭
    Re: welding cable

    Welding cable has worked for me... so far.

    I felt a bit paranoid during my install so all my crimps are filled with dielectric grease and all my connections have a dab of vaseline over everything (lug and terminal) to keep debris and corrosion away. My thought is that anything that keeps corrosion away (via the exclusion of humidity, water, and oxygen) is generally a good thing.

    A quick note: the batteries are in a relatively constant temperature environment so vaseline (white petrolatum) is not at risk of liquifying and making a mess.
  • solarixsolarix Solar Expert Posts: 713 ✭✭
    Re: welding cable

    I believe that old John Wiles of NMSU says that fine stranded welding cable is unexceptable unless used with crimp connectors listed for that use which means none of them. He recommends coarse stranded wire which is of course hard to bend. Personally, I use the fine stranded welding cable but solder as well as crimp.
    Being from an electronics background, I have a hard time trusting any connection not soldered.
  • nsaspooknsaspook Solar Expert Posts: 396 ✭✭✭
    Re: welding cable

    An alternative to Vaseline is Deoxit for your protected electrical connections. A small drop bottle or jar will last a very long time and it really works on everything from main panel lugs to audio slide pots.

  • SCharlesSCharles Solar Expert Posts: 123 ✭✭
    Re: welding cable
    solarix wrote: »
    Being from an electronics background, I have a hard time trusting any connection not soldered.

    I solder almost all crimp connections in my PV system. Maybe not necessary, but easy to do. This includes battery to inverter cables, etc.

    I don't have any welding cable around here right now, so I cannot do a direct visual comparison, but the cables that came with my forklift batteries are very fine stranded, [provided by the manufacturer] so I would think welding cables would be just fine.
  • PhotowhitPhotowhit Solar Expert Posts: 5,650 ✭✭✭✭✭
    Re: welding cable

    I've been around this and other forums for a long time, and there isn't anyone here that has the strong objections to soldered connections.

    In the intrest of arguing the other side I've heard reports of crimp and soldered welding cables that break at the end of the solder drawn up into the cable. Typicaly it's were the cable is moved repeatedly. Others point out that the common failure in ectronics are soldered connections.

    I've never worried about it in a battery installation, though crimped is is code and as others have pointed out weelding cable also doesn't meet code due to the ultra finely stranded wire. Don't tell the inspector if we ever get one in my county, I already had purchased welding cable for my instalallation.

    When getting an estimate on my fork lift battery, I did ask for an appliance side connector with 3' leads, so likely I'll be 'legal' shortly.

    FWIW - 2014 strands in 4/0 welding cable and 4-5000 in the really flexable stuff!
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • 2manytoyz2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: welding cable

    I work in the aerospace industry. Per our regs, we can either solder, or crimp, but we can't crimp and solder. FWIW, either are acceptable methods for flight hardware.

    Part of the issue is trying to crimp a soldered connection. The solder doesn't compress as well as unsoldered copper wires. Ends up failing a pull test. Also, if the connector gets hot, the solder can melt, and things can get "interesting" as the wire starts to slide out of the connector. This is why big power cables use compression fittings, not solder.

    Some of the industrial crimpers for large wire compress the termination so hard that the wire is almost fused together. I've seen pics of these cut apart after crimping, nothing short of impressive. I don't expect YOUR crimper to have these results.

    I have soldered connectors after crimping. It probably made no real difference, but it looked better having the ends of the wire tinned, and a nice solder fillet to the lug. That said, this was only on small conductor cables (~10 ga).

    Once I started moving up in wire size, soldering became much more difficult. Takes a lot of heat to get solder to flow in the ends of fat wire. Even with 6 ga wire, I ended up using a solder pot to tin the wire, then pre-tinning the inside of the lug, and finally heating up the wire and lug just prior to cramming them together.






    We are also required to have the insulation back about the thickness of the conductor for a visual inspection, prior to covering it with heatshrink. This wasn't a work project, but old habits...

    I must say, soldering 6ga wire was PITA! No way I'd attempt that on 4/0 cable. I use an anvil type crimper instead. Makes decent crimps in a fraction of the time.
  • solarixsolarix Solar Expert Posts: 713 ✭✭
    Re: welding cable

    I solder after crimping - have to use a small torch though. I can understand how in flight applications, you don't solder as you loose the wire flex and under vibration, small wires break right there where the tinning meets the stranding. I don't think soldered 2/0 awg is going to break in your battery box even if you have an earthquake.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: welding cable
    solarix wrote: »
    Being from an electronics background, I have a hard time trusting any connection not soldered.

    You speak for me as well. First the crimp, then the solder, then I know its a good connection I can trust. Of course I make sure the cables at these connections aren't subjected to flexing beyond the initial installation.
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: welding cable

    something that also helps the cable/lug connection is use a 3" length of if possible glue impregnated shrink tube.if not available use 2 lenghts of plain shrink tube.. put them on one at a time ,wait for first one to cool a bit before putting on second one or it will shrink before you get it fully over the first one.
    cover as much of the lug as possible with the tubing.

    The most useful item you can own to do good lug/cable soldering. attached gas torch photo
  • 2manytoyz2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: welding cable

    I have a large iron at work. Takes a while to heat up, but has so much mass, that it easily heats up larger lugs.


    Fine for 6 ga (and smaller) connections. If you solder larger lugs, I'd recommend performing your own failure analysis. That is, cut one apart when you're finished to see how well the solder actualy wicked up in the strands of the cable, and inside the lug. I've not been impressed with the results with the hardware I have access to. I prefer the Thomas & Betts Blackburn compression type connectors. These are available online, or through places like Home Depot.



    They make these for 4/0 cable, but get VERY expensive. For the fat cable, I've purchased these crimp lugs instead: http://www.amazon.com/gp/product/B001E5GR5M/ref=wms_ohs_product_T2

    I can get 10 of these for ~$25 vs. ~$40 for a single T&B compression type lug.
  • RCinFLARCinFLA Solar Expert Posts: 1,393 ✭✭✭✭
    Re: welding cable

    If you solder welding cable go with Excelene. That is the rubbery insulation that is very heat resistant.
  • System2System2 Posts: 6,290 admin
    Re: welding cable


    I am new here, but enthusiastic about this topic. If I get carried away, please forgive me!

    After reading through this thread, I felt compelled to toss my $0.02 worth (inflation is terrible, isn't it?) into the discussion. I spend considerable time and, for me, considerable financial resources on restoring, repairing, and maintaining various "experienced" pieces of heavy agricultural equipment and an odd assortment of "street legal" vehicles. Like Mr. 2manytoyz day job, catastrophic failures are not acceptable. True, mine do not generally result in a "crash"; and, when they do, it tends to be low yield and in the horizontal plain instead of incredibly spectacular and vertical. Still, an electrical failure at the wrong time can set a couple thousand acres of the neighbor's wheat on fire; so, we try to avoid such.

    Over the years, I have learned a wee bit through trial and error. I have made a number of improvements over "stock" (funny, in 1938, they didn't have all of the design bugs worked out; yet, they did some things better than we do today). Here's what I've observed:

    1.I have seldom seen a crimp joint break, next to the joint, because of flexing.
    2.I have more often seen a solder joint break, next to the joint, because of flexing.
    3.I have seen corrosion build up inside of a crimp connector (on the end farthest from the battery, no less!) to the point where the cable would no longer conduct electricity -- even though the connection remained mechanically strong!
    4.I have never seen corrosion increase the resistance inside of a solder connector.
    5.I have seen wires pull out of crimp connectors.
    6.I have not seen wires pull out of (properly done) solder connectors...
    7....unless the solder connector overheated, and the solder melted, at which point...
    8.I wished I'd had a crimp connector because that would have retained the wire at high temperatures.

    I have build a number of jumper cables for our various vehicles. They are typically made out of "#1" or "0" or "00" welding cable – depending upon length. Since I make them long enough (typically 25 feet) to jump the vehicle when the assist vehicle is parked to its rear, most are at least "0" – Right away, I fell in love with (high-temperature insulated) welding cable, but had problems connecting these cables to the clamps. Based on my experiences, above, I finally settled on the following procedure for attaching welding cable to jumper-cable clamps, battery connectors, ring terminals, et cetera. Basically, I solder, then crimp, then solder. Let me explain.

    To start, I decided early on that "electrical/electronic" solder was not suitable. Even most of the new RoHS compliant stuff doesn't "do it" for me. Consequently, I moved into the plumbing world and picked up some Tin/Antimony/Silver/Copper & Nickel solder – it melts just shy of 600F. Thats as much as 200F higher than "conventional" 60/40 solder – so "melt out" is less of a problem. I couple that with the best "tinning" flux I can find. The process goes like this.

    1.Strip and prep (twist, dry-fit, et cetera) wire.
    2.Flux the inside of the connector AND the wire. Heat the wire gently to be sure the flux "wicks" into the twist – you may see the "tinning" start (hence, the first "solder" step). Do not let the wire get hot enough to bond the strands with the "tinning" operation. Depending upon the flux, I sometimes heat the wire, then "dip" it into the flux container.
    3.Heat the connector – let the connector become cleaned and tinned – shake off the "excess" flux & tinning.
    4.Insert the wire into the connector and crimp to usual standards. (For "ought" wire, I usually put about 150 to 200 lbs of "test pull" on the crimped connector at this stage.)
    5.Re-heat the connector and flow the solder. The solder should "drive out" the flux (id est: don't over-temp the connector and "burn" the flux! Solder is heavier, if the connector is pointed cup-up, ring-down, the solder should fill from the bottom and the flux should flow out the top just ahead of the solder.
    6.Install a hot-glue-impregnated heat-shrink sleeve over the connection. I use the ones, available at the local electrical supply house, that are designed for protecting underground splices on direct burial cable. The heat-shrink, if done correctly (don't over-cook this either), will be slightly stiffer than the original cable. This should transfer the bending moment from the point right behind the solder joint, to a place an inch or two back from the joint and distribute it over a longer section of cable. (Note: for smaller cables, say #6 or smaller, with heavy insulation, allowing the solder to "wick" a short distance into the insulated portion often works as well for preventing flex that will break the cable.)

    Since I started doing this, I've not had any problems with corrosion inside of terminals, broken wires, solder "creep," or the other issues that have typically plagued "stock" installations.

    OBTW: nsaspook mentioned "Deoxit" – an oxide inhibiting "grease" for electrical connections. While I do not use this inside of these connections (I'm soldering, remember), I use "DE-OX" or "NoAlox" on all of my screw, clamp, or bolt connections – especially the battery terminals. For top-post batteries, I have a lisle battery post "cleaner" with is actually a "reamer." (No "wire-brush" cleaners for me!) It has the same "profile" on both the male and female ends. I use it on the terminals and the posts until I get a "clean" surface all around. I then coat all exposed parts with the oxide inhibitor, install the terminals and tighten, then coat all exposed surfaces with the "grease" to prevent air or electrolyte contact.

    Typically, the only time I ever have to "service" any battery connections is when I replace the battery. I usually get 30% to 50% longer than the rated life of the batteries, too! A 60 month battery, for example, will typically last about 90 months; so, absent any maintenance that requires physical removal of the battery, I typically "clean battery" posts on any give equipment every 7 to 10 years. (I routinely install battery cut-off switches for routine maintenance that would otherwise require disconnecting a battery terminal.) Oh, and I also replace the factory bolts (even on new terminals) with bolts, washers (where needed), and acorn nuts – all made of stainless. So far, I haven't had to replace any bolts or other hardware on any equipment or vehicles after doing this.

  • keyturbocarskeyturbocars Solar Expert Posts: 375 ✭✭
    Re: welding cable

    Interesting to read, 101. Thanks for sharing your experience.

  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    Re: welding cable

    If you are going to use Stainless on Stainless for bolts and nuts--Make sure to use anti-seize compound on the threads. SS galls very easily and you will twist the bolts apart rather than un-seizing the threads.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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