Victron uses TAILCURRENT settings which you need to use in your Charge profile. Additionally your charging profile is more than likely pushing too far. This is a path many have travelled. Please understand that the BMS is "Last Line of Defence", the basic JK's do their job well and manage the packs properly when setup properly. The BMS settings are to protect the cells and to manage the active balancing (which should be set to start @ 3.420V per cell.)
To figure out TailCurrent the formula is simple. 100AH X 0.05 = 5A, 280AH X 0.05 = 14A. This is NOT collective, if you have 2x 280AH then you use 14A as the TailCurrent/EndAmps.
This is what the SCC's see and act upon. When charging the Amperage the packs takes drops as they will up, once they have dropped to TailCurrent Value they transition to FLOAT (Constant Voltage / Variable Current) which tops off the battery packs in trickle mode allowing the balancers to do their work "gently".
Charging Profile MUST be Reasonable & Moderate and within working specs. Partly the general misunderstanding is that the Voltage Range for LFP is often misstated improperly. LFP has 2 Voltage Ranges like all other chemistries. The ALLOWABLE range which causes no harm or damage is from 2.500 to 3.650 Volts per cell. The WORKING RANGE (which delivers the specified rated AH) is from 3.000-3.400 with Nominal Voltage (50% SOC) being at 3.200V. This is the Capacity Determination range for Factory tests. See below.
CHARGE PROFILE FOR SCC's.
All equipment MUST BE Voltage Corrected & Calibrated (VERY IMPORTANT)
Bulk / Absorb: 55.2V (Absorb for 45 minutes (3.45vpc)
(some call this boost)
Equalize: OFF
Float 55.0V (3.437vpc)
MIn Volts: 42.4V (2.650vpc)
Max Volts: 57.2V (3.575vpc)
Rebulk Voltage: 51.2V (3.200vpc)
End Amps/TailCurrent: *1 (Triggers change from Absorb to Float)
(*1): End Amps is calculated: (100AH X 0.05 = 5A or 280AH X 0.05 = 14A.
EndAmps = TailCurrent
Coulumbic Efficiency / Battery Status Meter Efficiency for LFP = 99%.
This gets the bank charged to full with high amps (Constant Current Constant Voltage) and then float (Constant Voltage, Variable Current) tops off so the cells are at 3.437Vpc. I
! Do Not forget to adjust for Voltage Offsets between Actual Voltage @ Battery Terminal & at Solar Controller.
BMS With Active Balancing should be set to start Active Balancing at 3.420V or possibly lower to 3.410 so that the cells can balance out at the top and not affect the charging process.
Very Special NOTE: Floating & Saturating to 3.437vpc, accounts for the Voltage Settling post Charge of any kind which actually brings the cells to just below 3.400Vpc.
JKBMS Settings: NOTE, Default Values for LFP are NOT GOOD, check & set ALL Parameters
(ps I am the Steve_S that wrote the manual)
See my example here for a Solid BMS Profile, NOTE the temps & other corrected settings. This is an 8S Pack but all values are same for 16S.
NB: This is for the Standard JKBMS, not the Inverter Edition.
<--- This should match actual voltage @ pack terminals.
<--|
- Always leave a bit of room to restart pack and to not overdraw from cells.
- This also allows for a deep surge that will temporarily drop voltages
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<---|
<--- Starting lower compromises efficiency. 3.40-3.43 is best range for above profile
<- Depends on model of BMS you have
<-0.5C rate of pack.
<- Pending on model, 100A/150A/200A
<---- Temperature Defaults are incorrect ADJUST
-- These are the Chemistry Limits that apply.
--
--
--
<--
<--- User Field for naming packs.
SPECIAL NOTE:
The above settings are for the Standard JKBMS with Active Balancing. The Inverter Edition with Comms etc have many more settings & adjustments as well as interoperability with Victron & Other Inverters etc.
Hope it helps, Good Luck.
