Looking for Busbars for a LiFePO4 battery bank

Dusty
Dusty Solar Expert Posts: 271 ✭✭✭
edited August 2018 in Grid Tie and Grid Interactive Systems #1
I've been looking at BMS-controlled LiFePO4 batteries to replace my AGM battery bank when the time comes, and the battery mfrs stress the importance of every parallel battery cable being the exact same length as the others.  So, I plan to use a positive and negative busbar that will allow me to combine the outputs of the batteries and ensure that each battery's pos. and neg. cables are identical length.

The mfr recommends at least #4 wire from each battery, and I intend to use #2 with or without lugs on the busbar side. But the input to the XW4048 is 4/0 lugged wire, so the busbar has to be able to incorporate that.  The busbars I've seen on NAWS don't appear to support a wide enough range of cable gauges. 

The problem I'm having is finding code compliant, covered, 8-stud busbars with 3/8" studs (the maximum # of batteries that will fit in my enclosure is 6).

My battery enclosure is 42"L x 18"D x 26"H, so the busbars need to be small enough to fit in that enclosure. The XW 6048 is mounted to the side of this enclosure, so the busbars cannot be outside of it. The batteries will be in two rows of 3 at the bottom of the enclosure, and there is room above the batteries for the busbars.

If anyone has set up a similar LiFePO4 battery bank, would you please provide where you got the busbars?  Thanks!
XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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Comments

  • karrak
    karrak Solar Expert Posts: 326 ✭✭✭✭
    #2
    Are you making the battery from single 3.2V cells or 12V blocks with integrated BMS or something else?
    What is the configuration, how many batteries in series and parallel?

    Simon
    Off-Grid with LFP (LiFePO4) battery, battery Installed April 2013
    32x90Ah Winston cells 2p16s (48V), MPP Solar PIP5048MS 5kW Inverter/80A MPPT controller/60A charger, 1900W of Solar Panels
    modified BMS based on TI bq769x0 cell monitors.
    Homemade overall system monitoring and power management  https://github.com/simat/BatteryMonitor
     

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  • Dusty
    Dusty Solar Expert Posts: 271 ✭✭✭
    edited August 2018 #3
    karrak said:
    Are you making the battery from single 3.2V cells or 12V blocks with integrated BMS or something else?
    What is the configuration, how many batteries in series and parallel?

    Simon
    The batteries I'm looking at are 48v, 69Ah with integrated BMS as drop-in replacements for my AGMs.  They cannot be rigged in series--only parallel, so it will eventually be 6 parallel batteries in the enclosure.  I may start out with only three, but I'm told that additional batteries can be added later without the balancing worries of FLA or AGM.

    So I will only need two busbars capable of accepting 6 battery inputs of 2-4 gauge cable but support output to the inverter's 4/0 cable.

    XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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  • jmb
    jmb Registered Users Posts: 42 ✭✭
    #4
    Do they have to be store-bought or can you roll your own?  I made bus bars from 1/4" copper bar stock, drilled/tapped holes, and installed SS studs.
    Justin B.
    Cabin - 9 Mission Solar 310 watt panels, MidNite Solar Combiner, Iron Ridge mounting, 4 Speciaized Power 200 AH 24V LiFePO4 batteries, Samlex PST-1500-24 inverter, MidNite Solar Classic 200SL CC

    Barn - 9 Renogy 100W panels, Generic Chinese 40A MPPT CC, 6 Universal 12V 100 AH AGM batteries, Reliable 3KW 12V PSW inverter

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  • Dusty
    Dusty Solar Expert Posts: 271 ✭✭✭
    #5
    Very nice!
    XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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  • I_Boondock
    I_Boondock Registered Users Posts: 3 ✭
    #6
    Dusty, I'm not sure what your code requirements are, but can you use a BlueSea PowerBar 1000? I've used several for off grid, multiple charger, high amperage installations and they work well. P/N 1990 has 8 3/8" studs.
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  • Dusty
    Dusty Solar Expert Posts: 271 ✭✭✭
    #7
    Those look good @l_boondock! It will be a while before I replace my AGMs, since they are still working fine.  I'm looking into the Discovery AES batteries, since they have xanbus. But by the time I'm ready to buy, perhaps other MFRs will support xanbus too.  Thanks for the bus bar information!  The 600-amp model would be plenty for my small system. 
    XW6048, 3.4KW PV, Grid-Tied, always tweaking.
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