Bus bar connection between battery terminals on Surrette 4ks21's

Has anyone used a bus conection between battery terminals when connecting a bank of Surrette 4V 4KS21's? Would like to know where I can purchase if you have. Was just curious if it would be better than 4/0 cables.

Comments

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    if making the connections with a bus then you should know what the equivalent wire gauge will be for the bus. obviously if the gauge is not what you want then go with the wires, but i'm sure there are companies out there that make buses and would accommodate your needs if special. a bus can make for better connections, but at the cost of some play in the batteries' physical layouts. your call.
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    IM not wanting to get into another discussion on bus bars again but just reposting the post from a long time ago and the results for FARMERJOHNAZ to see if this answers his question..
    It shows the very tiny losses you get from using cheap copper tube available from any hardware store.. you just hammer or put in vice the ends of the short lengths of tubing to flatten them then just drill a suitable sized hole each end..

    Here is the results of resistance testing and mechanical destruction testing of lugs on copper wires as used in battery interconnects and similar usage.

    A total of 10 lengths of copper water pipe was purchased from hardware and plumbing supply stores. The 2 sizes purchased had inside diameters or 1/2 "(12.5mm) and 3/4" (19mm) thickness ranged from 1.25mm to 2mm. All pipe lengths were 10ft (3050mm)

    Each size and thickness of pipe was purchased from a different supplier
    All measurements were carried out on a calibrated desk multimeter.With a accuracy of+ or - .02%

    1.1/2 pipe 1.25mm =.0012 ohms

    2.1/2 pipe 1.25mm =.0013 ohms

    3.1/2 pipe 2mm soft = .0008

    4.1/2 pipe 2mm hard = .0009

    5.3/4 pipe 1.5mm = .00065

    6.3/4 pipe 1.5mm = .00061

    7.3/4 pipe 2mm soft= .00042

    8.3/4 pipe 2mm soft = .00041

    9.3/4 pipe 2.2 hard = .00040

    10.3/4 pipe 2.1 hard = .00039

    As noted the resistance was given for 10ft lengths of pipe . If we are going to use any of those pipes as barttery interconnects etc obviously the length used would be about 8" to 10 ", so to get the resistance you would have to divide the above resistance figures by about 12.

    To give worst case example the 1/2 pipe 1.25mm at .0013 ohms per 10ft divide by 12 =.0001ohms per foot
    THe loss across that pipe used as a battery interconnect would be using 24v connected to a 100 amp load = 40ma
    Now lets see how that compares to using a #2 cable and 2 lugs cable resistance = .00052 plus 2 crimped lugs at .00046 total resistance = 99ma loss

    Any talk about wondering about losses for 1000 ft of ANY 1/2" copper pipe can clearly be shown to be a pointless exercise. and it way surpasses using #2 cable and the fact is most people would only be using #4 cable as interconnects.With far far greater losses.And as I said in a much earlier post use 3/4 " copper pipe.No matterif it has many impurities its still far far ahead of #0 cable for battery interconnects

    Tests involved to measure lug on wire resistance and mechanical strength.
    the tests involve #4 cable and closed ring closed tube copper lugs 2mm thick

    1.Lug compressed with 500lb pressure on 3 serrated teeth jaws. resistance .00023 ohm.Lug then tested for breakaway

    .seperated from cable at 223lbs pull

    2,Lug compressed with 500lb pressure on 3 serrated teeth jaws then lug heated and filled with resin cored solder.

    resistance .00015 seperated from cable ..failed as cable broke before cable seperated . test pull 325lbs

    3. lug and cable resin cored soldered only. resistance .0008 seperated from cable at 127 lbs

    As you can see solder only is not good. As a further test the joint melted when a 140a load was connected to the cable and a 12v battery to the lug. Obviously not good.

    As you can see I didnt get much work done for employer the day I did all these tests, believe it or not it took 3 of us to do the tests .my work partner to verify the results ..As to do any destructive testing a workplace safety officer has to be present.
    Hope some of this helps people understand a little more about cables lugs copper pipes..
  • BB.BB. Super Moderators, Administrators Posts: 32,612 admin
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    Thank you John,

    Lot of nice information.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's


    john p,
    thank you and great info.
    :D
    i had looked for that info many many years ago and never got a straight answer. i only know of the l hard and m hard ratings to copper pipes here and i'm not sure which is the m hard on your list of pipe as there are 2 lesser pipes listed.
    also of note would be that anybody that uses the pipe for distances longer than the standard lengths will need to connect them (ie pipe to pipe) and just soldering will not yield a low loss connection. in addition to a voltage drop increase from soldering, the high resistance point could heat up and this could melt the solder.

    consider placing this up into the upper section of the forum after streamlining it a bit as this is great reference material.
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    Agreed, excellent information.
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    Thank you everybody that has found the information useful. I can assure all that the results are truely accurate. they were measured under as close to perfect as the equipment allowed.
    It interesting many people have now read the information but when I posted it earlier in the year it was not noticed by more than 2? people.

    As for hard and soft copper despite what you have been told the electrical properties are just about impossible to seperate.. Some of the pipes were "hard"some "soft" Each was shown in the list.

    I would never recommend soldering 2 or more pipes together for long lengths..The only way to connect them would be to braze them. even then dont know if that would be good? great?? I think if you need to go long lengths use normal plastic covered copper wire.
    The main advantage of using solid bus bars to interconnect batteries is the reduced number of connections.. lug to wire.. Its harder to get a really low loss connection with lugs if you dont have very good crimping equipment.. not handyman tools..
    For me we have that equipment at work but the best lug to wire never equals solid buss bar..
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    i did remark about it then too, but i seemed to have forgotten about it since then and until now. i'm not what i used to be.:cry::confused::p
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    No problem Niel .You get to see over time thousands of posts no one expects you to remember all. Im just happy that people have had a chance to see measured results not just words from people that are only repeating something told to them that may or may not be accurate..
  • farmerjohnazfarmerjohnaz Registered Users Posts: 7
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    Just looking for UL or ETL listed busses for connecting batteries. I don't think that flattened pieces of copper pipe have any value in a properly permitted system. Don't want the inspector making me the poster child for "how not to do it".
  • audredgeraudredger Solar Expert Posts: 272 ✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    Not sure I have seen any UL listed made up cables ... UL listed wire & UL listed lugs but nothing made up.
  • BB.BB. Super Moderators, Administrators Posts: 32,612 admin
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    You can find cabling houses that are "UL Approved" and will give UL Red Tags (for tracking purposes) if UL Traceability is required.

    I don't know if any of them do battery harnesses for the average home owner.

    I believe that NAWS may built to order battery cables. You would have to call them directly to get more information. (I don't work for NAWS or know any details about their operation).

    Ring lugs
    Welding Cable (10' minimum length)
    Welding Cable Specifications

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • sawmillsawmill Solar Expert Posts: 93 ✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    For all types and sizes of copper try www.stormcopper.com
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    Farmerjohnaz I have never seen a UL stamped copper bus bar yet for connecting batteries, And out of curiosity had a look at all bus bars we have at my workplace and nothing stamped on any of them.
    I believe if you go to any place that sells copper they wont have UL listed copper to use for bus bars,, but mabe you can find one that does..
    Many many people use welding cable for batery links and it certainly does not have a UL stamp of aproval as a battery interconnect..
    My post was only to point out that copper pipe used for interconnects was electrically supperior to just about any wire plus 2 lugs combination.(copper pipe has the lowest resistance).Reason :there is no joins to ever corrode.
  • VicVic Solar Expert Posts: 3,145 ✭✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    My 2-cents ...

    Cables provide several advantages, They are compliant during temperature cycling, and they ARE INSULATED.

    If your battery bank experiences much temp cycling, this can cause the connetions to work and loosen over time.

    Busses are usually not insulated, which is much more exposed to accidental shorts.

    Really, Bus Bars should be tin-plated to reduce corrosion potential.

    Cables are used as interconnects in most of our battery systems, so inspectors should be fairly well-versed in their use.

    Just MHO, Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    although i show no preference in method, i should mention in defense of buss bars that you can get them with alloys or coatings otherwise this would not be so for the electrical boxes we have today. now i will grant that some small expansion and contraction can occur in a buss and this may be a problem if one connects the buss directly to each battery as this will cause some small (and i do mean very small) bucking. many systems utilize equal lengths of wire from the batteries and tie together in a buss. as to insulation there is shrink tubing and other methods as well to provide some insulative quality to the buss even if one goes on the cheap with electrical tape.
    hmmm. i just had a brainstorm on how to equalize connections from multiple batteries down to a single point in a buss equally, but to my knowledge this has never been done before. as such i won't reveal my idea until i research this some more. who knows i may get patent.:confused::cool: yea right.:roll:
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    If you have a look at the batteries in diesel/electric locomotives you will find the inter connections are solid brass..they last from what I was told the life of the batteries .. 15 yrs.. vibration .cold does not seem to make the connections come lose or fail in any way.
    All the batteries I have seen in telecommunications buildings use solid bus bar..and they seem to be ok just about forever..
    At my work place all the batteries have solid interconnects, the battery banks are anything from 1000 ahr to over 15,000 ahr. and many different types of batteries.
    To me it hard to believe a solid piece of copper about 6"long is ever going to buckle no matter how cold then hot the air temperature.. if it true there must be huge problems with buckled ,broken joints on hundreds of feet of copper pipe used for home ands buildings !!!
    most places the air temperature does not go from -30f to 110f.in one day..

    Another point as Niel pointed out you can get heat shrink insulation to put on the solid bars if you really want to at very little expense.. But having said that I have never seen a bank of batteries with all the batery terminals covered with insulation.
    Bus bars in circuit breaker boxes used for domestic and industry are not plated just bare copper. well every one ive seen anyway. mabe in USA ????
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    john,
    i was giving the benefit of the doubt when it came to expansion and contraction of the metal that when batteries may be physically tied in this manor and they were tight during the hot period that during the cold the bar will pull the batteries tighter. it is true for all things that during hot and cold times that it will expand or contract to some degree and not always the same amount. i do agree that imho it should not be a problem.
  • nsaspooknsaspook Solar Expert Posts: 396 ✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    A simple and cheap way to cover buss bars is with water pipe split insulation. It really works well with copper pipe interconnects. (that's what it was made for);)

    4845904677_1172152077.jpg
    4845905533_91f1ef561a.jpg
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    great idea nsaspook. i was also thinking of those split covers they use to bundle wires together may work well for insulating a bus.
  • john pjohn p Solar Expert Posts: 814 ✭✭✭
    Re: Bus bar connection between battery terminals on Surrette 4ks21's

    simple fact about solid copper bus bar expansion due to temperature changes
    if you go from a low 10deg f to 120 deg f (-12 deg c to 48 deg c) about the maximum ever likely in any one place
    A copper bus bar 8"(203mm) will have a linear expansion of .009 inches( .24mm)
    Thats a BIG 9 THOUSANDTHS OF AN INCH.. For a 110 deg f change in temperature..
    Now if we assume we set up the batteries at a temp of about 65 deg f(18 deg c) then the contraction or expansion is never likely to be more than .0045 inches (.12mm)
    Enough to loosen connections???I doubt it..
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