Victron BMV-712 Smart showing %100 prematurely

yrtrncyrtrnc Solar Expert Posts: 43 ✭✭
Hello

I have recommended settings for lifepo4 batteries but when charge reaches about %80 it shoots up to %100. Can you please help with the settings. 

Regards 

Comments

  • yrtrncyrtrnc Solar Expert Posts: 43 ✭✭
    Any help with battery monitor settings? 
  • mike95490mike95490 Solar Expert Posts: 8,292 ✭✭✭✭✭
    You really need to read your battery manufacturers documents and set your charge controller accordingly.   Overcharging Li batteries can quickly (in hours) damage them .    Settings may vary between mfgs.
    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

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  • Raj174Raj174 Solar Expert Posts: 674 ✭✭✭✭
    yrtrnc said:
    Hello

    I have recommended settings for lifepo4 batteries but when charge reaches about %80 it shoots up to %100. Can you please help with the settings. 

    Regards 
    What settings are you using and what type of LFP battery is it?
    3600W PV, MNE175DR-TR epanel modified, MN Classic 150, Outback Radian GS4048A, Mate3, 54.4V 195AH LiFePO4 no BMS, 4500W genset.
  • mcgivormcgivor Solar Expert Posts: 2,912 ✭✭✭✭✭
    Lifepo4 batteries are extremely sensitive to overcharging as well as over dischargeing, the voltage should be controlled at the cellular level, not the string voltage,. Without knowing what you have its impossible to recommend anything so details are needed.

    1.  Are the batteries modular drop in type or loose cells ?
    2.  If loose cells were they ballanced before use?
    3.  If loose cells do you have a BMS connected? 
    4.  What is the nominal voltage? 
    5.  What settings are you using?  


    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • yrtrncyrtrnc Solar Expert Posts: 43 ✭✭
    Hey guys

    Thank you for your replies. It's not the settings for the charge controller that need adjustment. It's the settings for the battery monitor. The battery monitor show the batteries are a 100% when they are 80%. The batteries are victron brand. 
  • EstragonEstragon Registered Users Posts: 3,729 ✭✭✭✭✭
    I'm not familiar with your specific monitor, but in general they reset to full when charging current drops to 'X' amps for 'Y' amount of time.  The values for X and Y are often adjustible, so you can adjust for the tendency of some battery types to take more current at 100% as they age, for example.

    The charge controller may use a similar algorithm, or may just hold voltage for some preset time.  Lithium setting typically keeps this time very short or just ends charging on reaching terminal charging voltage to avoid overcharge.  As others have noted, unlike flooded lead acid, lithiums are sensitive to overcharge.  They have pretty flat voltage across the SOC curve, but with steep tails at the top and bottom.  As voltage rises very quickly when the battery is near full, a conservative charger will terminate before this point.

    This means it's possible the controller isn't using a conservative approach, and may be doing a longer absorb stage, which is likely inappropriate for your battery.  Another possibility is the monitor has settings causing it to prematurely reset to 100%.  To determine which it is, I'd suggest comparing the controller charge settings with those in the monitor.  If you post these, along with battery details, members here with lithium experience may be able to help more.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Blackda3Blackda3 Registered Users Posts: 8 ✭✭
    I can't find a post directly on point but I recall reading several posts on the following forum having to do with adjusting the battery monitor.  See:  https://community.victronenergy.com/index.html
    1996 LX450; 2017 Aliner Explorer: 3 x 105 Ah AGMs; 2 x 140w Kyocera panels connected to a Bogart TriMetric and solar charge controller; Remote deployable system of two/three additional Kyocera panels connected to a Victron MPPT 100/50 Solar Charge Controller.
  • mcgivormcgivor Solar Expert Posts: 2,912 ✭✭✭✭✭
    yrtrnc said:
    Hey guys

    Thank you for your replies. It's not the settings for the charge controller that need adjustment. It's the settings for the battery monitor. The battery monitor show the batteries are a 100% when they are 80%. The batteries are victron brand. 
    How have you determined the battery is only 80% charged ? With lLifepo4  batteries when the target voltage set-point is reached the BMS will terminate current to preserve the battery, there is no absorption stage, if the battery monitor is calibrated  for lead acid it may see this transmission as being 100%. The monitor under normal lead acid conditions would expect a decline in current to a specific value then go into float, since the is not the case with Lifepo4 the monitor would assume full charge when current drops to zero, it would be because it is fully charged, hense the rapid change from 80-100%
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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