Off Grid charging problem

myrasouza
myrasouza Registered Users Posts: 1
Any help would be appreciated. We are new to using Lifepo04 batteries in our solar system. System is 48v with 32 500ah batteries. Connected 2 batteries together to create 1 16s 1000ah batteries so we only need to monitor with 1 BMS. We have the Schnieder 6848 Inv, MPPT 100 600 CC. We have 20 385w panels. We have Westerbeke 7.0KW BCGB 60hz single phase generator. We can not get the CC to charge the batteries to balance at 3.4-3.5 without one running away and stopping the charge. Is there a manual or guide that shows what everything in the SCP should be set at? Also the generator only wants to run on AC1 not AC2. It's seems we have the parameters set wrong or somethings wrong with the CC. The solar array is only bringing in 200w in full sun.

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Don't you need two BMS's for two batteries ?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Do you have a designer/installer or was this a do it yourself install?

    I think we will need more details... Brands/models of BMS, XW model and firmware level. SCP firmware level, etc...

    Has the system ever run correctly?

    What does battery runaway look like? All cells "over voltage" or near over voltage? One cell group very high, rest normal? What current/power is being fed into battery bank when voltage runs away? Has to be more than 200 Watts of solar?

    Do you have a DC Current meter and can measure the currrent flow into and out of each 1/2 bank of batteries?

    Two banks, two BMS, but only one BMS connected to XW system? Other one runs free and will only cutoff batter if over/under voltage or current specifications?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    With cells paralleled for 1000 AH your BMS balancing is likely inadequate.  The fact you stated 3.4v for balancing probably says you are using a resistor dump balancer.  Once cell get to 3.4v where balancing starts it is a race to get all cells balanced before one trips overvoltage shutdown on BMS.  With 200 mA resistor dump balancing current and 100 amps of charge current you are fighting an unwinable battle. 

    The higher the charge/discharge current the greater the progression toward imbalance.  When charging cell voltage reaches 3.4v it rises quickly giving little time for balancing before overvoltage cell shutdown by BMS.

    I recommend you get an active balancer capable of 5-10 amps of balancing current for 1000 AH battery.  A 200 mA resistor dump BMS balancer will never keep up.