Battery inter-connects

verdigo
verdigo Solar Expert Posts: 428 ✭✭
in Solar Beginners Corner #1
I see pics of some people's battery banks with steel bars for inter connections. are these ok?

Dennis
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Battery inter-connects

    Not the best idea.
    For one thing steel has higher resistance than copper. For another, rigid bars are rigid making placement and proper tightening a bit of a task. Then there's the ever-present danger of one great big exposed conductor out in the open.

    I tried rigid copper bars; didn't like them. Went back to wires.
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #3
    Re: Battery inter-connects

    I may have been looking at copper in the pictures. I'll defer to your experience though.
    Thanks
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #4
    Re: Battery inter-connects

    My, and other, AGMs come with tin plated-copper interconnects.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #5
    Re: Battery inter-connects

    Another reason to avoid rigid interconnections is that as a battery ages its geometry changes... the positive terminal will often protrude a bit. Having a rigid interconnect on a moving terminal will lead to stress on the terminal. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • sunbunny
    sunbunny Solar Expert Posts: 59 ✭✭✭✭
    #6
    Re: Battery inter-connects

    Westbranch, can you tell us some more ? How long have you had them in use ?
    Do you have a picture ?
    I'm considering them for my AGMs.

    Thanks
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #7
    Re: Battery inter-connects

    Steel bars are certainly not the go for battery interconnects.
    If you dont want spend a lot of money use copper water pipe just cut to length you need flatten ends with hammer(rough) or in a vice. They work perfectly..3/4 " pipe is good size to use if you dont like exposed copper between the batteries buy a length of garden hose to cover them.(but really all the battery terminals are exposed??? so whats the difference ??? As for movement between the batteries with temperature changes it comes to a few thousandth of an inch for a temp change from 0 deg C to 40 deg C.. And very unlikely inside a building..Over a 20 year period you may have to re-tighten the connections once.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #8
    Re: Battery inter-connects

    Those who know avoid any rigid connecting bars, those who don't will eventually find out why.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #9
    Re: Battery inter-connects
    Blackcherry04 wrote: »
    Those who know avoid any rigid connecting bars, those who don't will eventually find out why.
    Really??? I don't think I will live long enough to find out as haven't found out the reason in the last 40 years. Mabe some of the other techs at work will discover it after I have retired.

    Is it now time to tell also the largest telecom company in Australia they have been connecting all their 2v cells wrong for about the last 60 years?? Mabe not, it better if they just wait and find out.

    It seems ignorance for us is bliss.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #10
    Re: Battery inter-connects
    john p wrote: »
    Really??? I don't think I will live long enough to find out as haven't found out the reason in the last 40 years. Mabe some of the other techs at work will discover it after I have retired.

    Is it now time to tell also the largest telecom company in Australia they have been connecting all their 2v cells wrong for about the last 60 years?? Mabe not, it better if they just wait and find out.

    It seems ignorance for us is bliss.

    The difference is in the application. A professional telecom install is not going to be the same as Joe Canadian's off-grid cabin system. It's all about flexibility; figuratively if not literally.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #11
    Re: Battery inter-connects

    Cariboocoot I dont agree with you. I dont see any real difference if you give Joe the Bartender 2 interconnects and a spanner and two batteries and have him connect them or a man/woman/other with an electrical , mechanical and space station engineering degrees .. If they are only capable of knowing how to tighten some bolts you will get same result.
    You will usually find Joe Canadian and his 37 friends only most likely use at most ?4 x12v batteries. in series parallel or just parallel.. It doesnt require great skills to either do this using solid interconnects or "00" wire interconnects. The reality is they will feel much the same and react the same to temp and "vibration?? I think but if you have vibration in your cabin its time to worry about more important things than your battery interconnects.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #12
    Re: Battery inter-connects

    John, you haven't seen all the off-grid installs I have. Most amateurs (and some pros) could not manage a proper install with bars. Heck they can have trouble doing it right with wires. :p

    I did try it myself. Worked fine (thermal expansion issues are like you say; not a real problem). But I did not like having the exposed connectors and having to build new bars if I get different batteries next time. Which I did, so I went back to wires.

    Never yet seen batteries in a non-mobile install subject to vibration or wire flexing either (two "issues" often mentioned which do not really exist).

    Wires are easy to get pre-made, fit even if you got the measurements wrong by a bit, and certainly conduct fine provided they aren't undersized. Plus most of the length is covered with insulation which reduces shorting risks and corrosion issues.
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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #13
    Re: Battery inter-connects

    I would say that cables are easier to work with and are safer because they're isolated. But cables cost more.

    If I had to roll-out 1000 installations that are all the same, I would go with bars.
    For myself, I went with cables.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #14
    Re: Battery inter-connects

    I have a bucket of old buss bars in my shop that I have removed in the last 20 years. It became a in vogue thing to make for a bank of batteries on factory setups. Some are copper and some are brass. All machined and bent on a brake to fit a specific set of batteries. 1 ) The problem is you'll never have two sets alike. 2) A set of FLA's are not telecom batteries, they swell and bulge over the years, the positive posts grow. I have personally seen a post ripped completely ripped out by a bar. 3 ) Once you loosen the nut's on them you'll never get them off the post without beating them off with a hammer. Even with a bolted set the bolts will pull sideways and they are heck to get off. 4 ) If you have to remove a battery, you have to dissemble the whole bank, no way to isolate one battery and you'll have a hard time getting them back together. 5 ) They pull all the seals out of the top of the battery case and you have a nasty leaking mess around the posts.

    Anyone that think that water pipe is right for them, help yourself. I will say that you should check your connections once a year for cleanliness and tightness, once in twenty years is a little long.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #15
    Re: Battery inter-connects

    The argument of if you use bus bars they are exposed.. Well thats true but only if you haven't figured you can use cheap easily obtained garden hose to cover them. But what about the battery terminals. Are they not exposed?
    A fact often ignored but important.

    If you had 8x 6v batteries in series to get 48 v. You save a massive 28 connections by using bars not cables.
    It only takes one slightly bad lug to cable connection to cause major problems in a series group of batteries.

    We have found copper pipe so good to use at work after a very long time ago I did some testing and actually posted the results on this forum. somewhere. We now at work use more copper pipe for interconnects than cables. Its just so easy to make them any size and bends to suit any batteries no matter how different they are to each other. And dont have to worry about a bad lug /cable..

    Blackcherry04 I have never come across all the problems you seem to have found using bars as interconnects.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #16
    Re: Battery inter-connects

    Pretty easy to cover battery terminals and cable ends with a bit of grease.

    For your average amateur the cables are much easier to obtain and deal with.

    My PS2200's couldn't be connected with bars, btw, as it would mean going across some of the cell openings due to the location of the terminals and necessary placement of the batteries in the space available.

    Literally and figuratively cables offer more flexibility, something most people need.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #17
    Re: Battery inter-connects

    More good info here:
    http://forum.solar-electric.com/showthread.php?14879-Busbar-as-Battery-Interconnects
    http://forum.solar-electric.com/showthread.php?7629-Battery-interconnections

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #18
    Re: Battery inter-connects

    Thanks vtmaps for finding my old posts on the subject. I think they are just as valid today. Ans so much so that as I already said we have just about stopped using cables as interconnects at work..

    I just find it funny some of the reasons given not to use them. when the so called "rolls royce of batteries" Surette recommends them, so of course do many others.All the Lithium battery manufacturers recommend them only.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #19
    Re: Battery inter-connects

    Pretty easy to cover battery terminals and cable ends with a bit of grease.Im fairly sure that wont save a nice new pair of pliers dropped across the terminals.Watched a tech do that at Telstra Telecom one day just amazing the damage to them.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #20
    Re: Battery inter-connects
    john p wrote: »
    Pretty easy to cover battery terminals and cable ends with a bit of grease.Im fairly sure that wont save a nice new pair of pliers dropped across the terminals.Watched a tech do that at Telstra Telecom one day just amazing the damage to them.

    No, it won't do anything for shorts - but you have the same trouble with bar connectors.
    It does reduce the corrosion troubles though.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #21
    Re: Battery inter-connects

    Thats why I said you can easy cover the bar with cheap easy to obtain garden hose...im a professional cheapskate..
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #22
    Re: Battery inter-connects
    john p wrote: »
    Thanks vtmaps for finding my old posts on the subject.

    If we're ever in a room together, you'll recognize me instantly... I'm the one with google eyes :roll:

    Do this google search: "copper pipe" site:wind-sun.com and you'll find those posts and more on the first page of the search. -vtMaps

    ps: John, do you still have one of those batteries with the air bubble electrolyte circulation system?
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #23
    Re: Battery inter-connects

    This weeks job : Installed Sept 2006, Batteries down to 50 % capacity, All cells at 1.270 or so SG's. Factory installed Buss Bars ( 3/16 " x 1 " ) Identical Batteries not available within 250 Miles. Batteries show mild Positive protrusion. The question is what to do with the buss bars since they do not fit the new batteries. I personally do not like to cube up batteries like this because of the heat they retain. The bars will be heck to remove because of the swelling of the cases, they are down in a battery box. Marine code now calls for a yellow ground, in case you didn't know.



    Attachment not found.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,590 admin
    #24
    Re: Battery inter-connects

    Bus Bars do make for a very neat looking install.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #25
    Re: Battery inter-connects

    Sorry vtmaps all the batteries I modified were sent to a industrial disposal place.. As they had small holes drilled in the tops they were considered dangerous as if knocked over acid would spill out... No one was even allowed to move them from my work area to use.
    It cost them over $1000 to get them disposed of... Thats the cost of testing things. plus of course the cost of all the batteries and air pumps. Its why you would be hard pushed to find a solely commercial business willing to do such a test.

    Iagree it would have been good if could have kept them for long term test, but it wasnt allowed..I get away with a lot but sometimes.. NO.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #26
    Re: Battery inter-connects

    Looking at the photo Blackcherry 04 has it really is a neat install, and obviously very reliable. As he states installed 2006. Hard to fault the install.
    While its true putting all the batteries together tightly does make them run at a higher temp it hasnt affected the longevity of that batch.
    When I was working on luxury boats above 100ft.. They always had them packed like that. It certainly reduces movement that can cause connection problems. Its why Lithiun cells are always done the same way from what I have seen.
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