Need Help Configuring Bank to 24 volts

John XW NYJohn XW NY Solar Expert Posts: 50 ✭✭✭✭
Ok guys I am new here and need some help with my XW battery backup system,
Every thing is hooked up and seems to be working EXCEPT my battery bank is running down after 1 hour when I am running a small load( less than 1000w)

I suspect that my electrician did not correctly wire my battery bank correctly which is a 24volt system. I am using 12 Rolls s-530 6v batteries which are in 2 rows of six facing each other by depth( not the long way:-). I need a proper diagram to show me how to connect them both in series ad parallel. From what i have seen the positive should all be facing the same direction and the neg lined up on the opposite sides then the inverter cables connected on opposite sides,one to neg the other across the bank to get equal distrubution of charge. This much i understand.

Apparently my guy does not have the batteries all lined up correctly as i have seen on some other diagrams i have looked at. I should be getting plenty of power from my bank and should last way over an hour so obviously they are not hooked up right.
If someone could help me by sending me a proper diagram i would greatly appreciate it. I am concerned that my bank may get damaged a result of incompetence by my electrician. So i need to fix asap, Ive really tried hard to get it all working and would like to see it functioning the way it should.

JAH GUIDE. JD

MY SYSTEM 3.7 KW EVERGREENE SP, 24 V XANTREX XW4024 INV, XW CHARGE CONTOLLER, XW SCP, 12 ROLLS S530 BATTERIES
SOLAR BACKUP SYSTEM WITH GRID SUPPORT!!!

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need Help Configuring Bank to 24 volts

    Uh, you need to look at how the wiring goes in terms of (+) and (-) connections.

    Series connections for adding 6 Volts up to get 24 Volts:

    (-) Batt (+) to (-) Batt (+) to (-) Batt (+) to (-) Batt (+)

    Four 6 Volts connected this way = 24 Volts.

    Parallel connections for adding Amp/hrs together:

    (-) to (-) and (+) to (+)

    Twelve 6 Volt batteries configured for 24 Volts would be three parallel rows of four batteries in series.
    For best results, the common (-) and (+) leads of each series string should be connected by equal length & size wire to a bus bar, and then to the inverter (with appropriate fusing).
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: Need Help Configuring Bank to 24 volts

    Also, more information on how your changing the battery's ( solar or off the grid with the inverter-charger ), is your configuration doing gridtie and what are the setting for the XW solar charger and Inverter will allow us to give specific tips on improving your performance
  • BB.BB. Super Moderators, Administrators Posts: 30,494 admin
    Re: Need Help Configuring Bank to 24 volts

    John,

    It does not sound correct:

    530 AH * 3 strings * 24 volts = 38,160 WattHours = 38 kWhrs

    So... What is the resting voltage of the bank, what is the Specific Gravity of all of the cells, what is the charging current/time/voltage?

    While their are "good" and "bad" ways of paralleling strings--this problem sounds like it is a whole bunch worse/different.

    Measure the voltage across each battery (each cell, if available) to 2.xx accuracy. Do this during charging and usage (look for high/low cells when substantial current is flowing).

    What is the voltage at the battery bus when charging at XX amps and under XX load, etc.

    If you think you have bad connections or undersized wire/cable somewhere... Put the battery under heavy current (charge or discharge) and with a Digital Voltmeter set to 2 volt max scale, go across each connection/cable. See that all voltage drops are small and similar. You can even go to the 200mV scale (0.2 volt) if needed for more precision at low voltage.

    You have some major problems. First thing is to make sure that battery bank (all cells) are charged... If they sit for months <75% state of charge, the bank can sulfate and fail much too soon (Months to a Few Years of life, instead of closer to 8-10+ years of life from a good set of batteries).

    -Bill

    Yikes, as was said by Marc above, 3 strings of 4, not 2 strings of 6--can be the exact cause of your problem (running batteries near dead).
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • John XW NYJohn XW NY Solar Expert Posts: 50 ✭✭✭✭
    Re: Need Help Configuring Bank to 24 volts

    oh they are supposed to be in three sets of four if i did not clarify that already. Like i said this guy hooked them neg to postive , not only inside (series) but on the outside as well where they should be wired parallel pos to pos., not pos to neg. Then string them together.... Maybe I am going to learn something here after all.:-)

    Thanks 4 the thoughtful replies so far. I am glad to see some solar solidarity here.
  • BB.BB. Super Moderators, Administrators Posts: 30,494 admin
    Re: Need Help Configuring Bank to 24 volts

    Here is an example of how to econnect batteries together in parallel:

    How to Connect Batteries Together

    Basically, you want the wiring (gauge and lengths) to be arranged so that they are balanced no matter which of the three parallel paths the current takes.

    If one path is shorter/heavier gauge wiring, then that battery will get much of the charging and discharging current--and the others will just sort of sit there with less deep cycling....

    Eventually, the battery string with the lowest resistance will fail first, instead of all strings aging at the same rate.

    If you have an asymmetric setup--(2 rows with 3 parallel stings)--it may be difficult to make a symmetric installation.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Need Help Configuring Bank to 24 volts

    would it be possible that you can take a pic or 2 of the setup and post it on here just so that we can be sure of things?
  • hillbillyhillbilly Solar Expert Posts: 334 ✭✭
    Re: Need Help Configuring Bank to 24 volts

    Just to be clear:
    Series connection- positive to negative there should be three "sets" like this consisting of four batteries each
    Parallel connection- would be positive to positive to positive connecting one "end" of these three sets, and negative to negative to negative connecting the other end.

    Check out where the inverter positive and negative wires connect, at each of those terminals there should be parallel connecting wires (inverter+ connecting to battery+ to battery+ to battery+ and same for the negative). How many of these parallel connections do you have? There are many ways that the wires could be configured, perhaps due to space issues... or perhaps just laziness??? Just verify how they are connected for us.
  • Solar GuppySolar Guppy Solar Expert Posts: 1,962 ✭✭✭
    Re: Need Help Configuring Bank to 24 volts

    Further, when you parallel banks, each series string should have over current protection, not hard wired together. A fault in one battery can cause and explosion otherwise as the good bank will dump all the energy into the bad bank without fuses or breakers
  • John XW NYJohn XW NY Solar Expert Posts: 50 ✭✭✭✭
    Re: Need Help Configuring Bank to 24 volts

    Ok Guys Update.

    I contacted Rolls and the battery configuration i am running appears to be correct according to them. Apparently the batteries need to be equalized and things will be fine. I am planning to do that and will post a reply when i have sorted it all out.
    Thanks a lot for your help and thoughts will update next week.

    Jah Guide JD
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