wire lengh question with copper bus bar for 3 banks of batts rolls L16 445ah.

offgridcabin2015
offgridcabin2015 Registered Users Posts: 88 ✭✭
i'm about to wire up  3 bank of batts /  12 - 6v batts into 24 volts.
i'll be using welding wire with copper lugs to wire batts into series. 

I know it' important to keep wires ALL THE SAME LENGTH . so question

do i makea the wires the same lenght from battery terminal to copper bus bar?

i'll attach my ei and batts.
you can see in this ie it' 48 v i'm doing  24 volt. 
this is bad ei for the red and black wires from batts to bus bar ARE LONGER here. I would think all wires need to be the same. 

so that the batts will discharge all at the same time. . thus not creating a weaker one vs stronger one battery.

2) The other thing i'm told / read is they say to keep the pos / neg battery wires near to one another like taped together for some reason. not sure if that really is  great idea or not , any thoughts or pics .

Thanks experts

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    edited June 2022 #2
    Bus Bars have resistance too... So, ideally, for example:

    Left side of your drawing--Bus bar connections
    Chargers +
    batt 1
    batt 2
    batt 3
    Inverter/loads +

    Right side of drawing--Bus bar connections
    Inverter/loads
    batt 1
    batt 2
    batt 3
    Chargers -

    That way, the "electron paths" are all equal. As you have drawn, the chargers and inverters "in the middle" means batt 2 has the shortest paths and the lowest resistance, and battt 1/batt 3 have longer total path lengths and higher resistance (comparatively speaking) and those batteries may/will share a bit less of the charge/load currents.

    Yes--Keeping +/- pairs of cables together is the ideal. For example, if the +/- cables are not together and run as a "loop"--You have a nice loop antenna and the wire runs become more susceptible to lightning energy and a better transmitter of electrical noise from your chargers/inverters/loads.

    For "different circuits" (say DC and AC circuits) they should not run in parallel/same conduit. You want separate runs to avoid cross talk between the circuits and if they must cross--Cross at right angles to each other.

    You did not ask--But another issue is when running wires into metal boxes (such as a breaker panel). For AC wiring, the Hots and Returns (L1, L2, Neutral) main power/branch circuits... Each "set" of AC power leads must enter and exit the "metal" boxes through the same hole/knockout.

    If you run an AC circuit of  L1 (black or red "hot" wire) through one knockout and return (neutral white wire) through a second knockout--That sets up a "transformer" situation and will cause circulating current in the metal box sheet metal itself. And can cause the sheet metal itself to overheat.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • offgridcabin2015
    offgridcabin2015 Registered Users Posts: 88 ✭✭
    Thankyou bill. i'll follow your wonderful advice. 
    #I appreciate  you 

    be safe and pics to come soon. 
  • offgridcabin2015
    offgridcabin2015 Registered Users Posts: 88 ✭✭
    PIC. of my work thus far