error in battery bank wiring diagram

vtmapsvtmaps Solar Expert Posts: 3,739 ✭✭✭✭
I was looking at some Magnum Energy product manuals and I think that there are some errors in their diagrams on how to hook up a series/parallel battery bank.

I have attached one of their diagrams for a 24 volt series parallel bank. I put two red arrows on the diagram pointing to the connections that I believe are wrong.

Am I correct about this, or am I missing something?

--vtMaps
4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,008 admin
    Re: error in battery bank wiring diagram

    That is a wild diagram....

    It is not wrong in the sense you will blow something up (at least I don't think it is).

    And you are correct if you pull the left red jumper and the right black jumper, then you would have a standard series/parallel connected battery bank.

    However, if you add those two jumper back in (and some people even add two more similar jumpers in the middle of the bank too)--It sort of allows cross string "equalizing" of current/voltage...

    I would not recommend it as the two strings should have almost zero volts difference at each of those jumper points if everything is matched and working well.

    And if you have a problem (say a shorted or open cell, or a poor electrical connection), the additional parallel wiring will just make debugging more difficult and could cause more damage (shorted or open cell, bad wiring, will cause other the interconnected bank to possibly damage its cells from localized over/under charging, etc.).

    At least that is my quick read of the drawing. But, be very careful when following any drawing/wiring practices on lead acid batteries... They can output 1,000's of amperes into a dead short (if the wiring is wrong)--and just ruin your day.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 32,008 admin
    Re: error in battery bank wiring diagram

    And add a link to a better diagram of how to "best" connect multiple strings of batteries together:

    www.smartgauge.co.uk/batt_con.html

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,655 ✭✭✭✭✭
    Re: error in battery bank wiring diagram

    Well you might not be use to seeing 8 batteries setup in a 24 volt bank, but it appears more than right, but exactly right! assuming the connection made at the battery terminals between the 2 strings is the same wire length/resistance.

    Might like to have fusing at the terminals for the 2 strings.
    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.
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