Bank charging question?

[yachtdr22]

Battery Bank Charging

I have 9 Battery 48v – 100a Lion Bank.
This is a mixed breed and I am wondering the best way to manage charging?
5 of these batteries are from ReBel Battery in Lake Jackson TX who is out of business.
4 of these batteries are EG4 Life Power4
The dates in service is also different.
I would have bought all EG4’s but didn’t know about them until it was to late.
My dilemma is unbalanced charging. Should I be concerned.
This bank is driving 2) Paralleled Sol-Ark 15k boxes. Settings on the Sol-Ark is to Lead-Acid as there is no BMS connection to the bank.
there are huge charging and discharging characteristics between all of the batteries and I am wondering if this is a problem?
Interesting how the EG4 Battery charge cycles are more then the ReBel that are in-service longer?
Each battery does have it’s own BMS to protect it, however some charge fully before the others therefore charging the Lakers at 50a.
Thoughts?
Thanks Drew

		Date​	Cycles​
Rebel Battery	1​	10/22​	310​
Rebel Battery	2​	10/22​	306​
Rebel Battery	3​	10/22​	314​
Rebel Battery	4​	10/22​	314​
Rebel Battery	5​	10/22​	319​
EG4 Battery	1​	12/22​	341​
EG4 Battery	2​	12/22​	341​
EG4 Battery	3​	1/23​	321​
EG4 Battery	4​	11/23​	28​
			1/5/2024​

https://signaturesolar.com/eg4-lifepower4-lithium-battery-48v-100ah/

https://rebelbatteries.com/products...d-rechargeable-lithium-iron-phosphate-battery

 

[time2roll]

My thought is to not worry about it. In ten years when a battery has 3500 cycles take it out and test capacity. Replace if needed.
Each year test any that are suspect of excessive degradation.

 

[Rocketman]

How is your wiring setup? That may (or may not) be part of the issue.

Also (because I have no idea on Sol-Arc specs), is the lead -acid settings good for the lithium?
Can you set a custom setting?

 

[yachtdr22]

How is your wiring setup? That may (or may not) be part of the issue.

Also (because I have no idea on Sol-Arc specs), is the lead -acid settings good for the lithium?
Can you set a custom setting?

All wire lengths were the same. I have even tried doubling the length on those batteries that were reacting faster and made no change.
I have manually adjusted all of the voltage setting in the Sol-Ark and that part has been fine

 

[LydMekk]

Can you post a photo of the physical wiring to all batteries?
Any busbars?
No washers between some plugs and busbars?

 

[Steve_S]

As these are all 48V/16S 100AH packs, that makes it a lot simpler... get's trickier with different sized packs in a bank, it's OK just needs more math...

Unlike the old FLA days, adding LFP to a bank is NOT an issue, so not much to worry about UNLESS you have a Weak Pack that does not get to full charge parity with the others... That can actually draw down a full bank to the lowest point due to the higher voltage packs will attempt to backcharge. That has to be pretty serious though... ie a pack with 1 cell that won;t go above say 3.200V that will pull that pack down and subsequently the bank. This si observable & repeatable.

The USER Profile is the most flexible because you can set "You specific use case settings" and not getting canned with a generic profile.
Suggested profile which will work with ALL Packs without requiring BMS to Inverter connectivity.... User Profle can still be used when connected but tweakages are needed. ALSO a GOTCHA ! If the EG4's are connected but not the Rebel Packs then problems will arise as the EG4's know nothing about their companions.

All equipment MUST BE Voltage Corrected & Calibrated (VERY IMPORTANT)
Divide Values X2 for 12V. Multiply X2 for 48V.
Bulk - Absorb: 55.2V (3.45vpc) Absorb Timer set to 45 minutes (some call Absorb Boost) *Absorb rarely runs the full 45mins because of EndAmps
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:*1) (** Allows for full Saturation at set Float Voltage)
(*1): End Amps is calculated IE: (100AH X 0.05 = 5A or 280AH X 0.05 = 14A.)
EndAmps = TailCurrent (depends on vendor)
Coulumbic Efficiency / Battery Status Meter Efficiency for LFP = 99%.

This gets the bank charged to full with high amps (Constant Voltage / Constant Current) and then float (Constant Voltage / Variable Current) tops off so the cells are at 3.47Vpc.
* Do Not forget to adjust for Voltage Offsets between Actual Voltage @ Battery Terminal & at Solar Controller.

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.

Do note that every Lug, Terminal, Fuse/Breaker, switch etc adds resistance to the cabling and subsequently voltage losses. While no single item is large, collectively it adds up FAST ! Be Certain that your Solar Charger is CORRECTED / Offset Compensated. If the SCC thinks it is charging at 55.2V but with losses the Batt Terminals read 55.0 you'll never get truly charged. ALSO on the Inverter, the CUT OFF LOW VOLTAGE MUST BE ACCURATE, you do not want it to shut off early or late... Again the Voltage @ Batt Terminals RULES, so correct for even the slightest difference. NB: It is best to use at least a 2 Decimal Point Accurate DVOM/DMM

UNLIKE LEAD ACID - LFP IS Millivolt & Milliohm sensitive.

 

[yachtdr22]

Can you post a photo of the physical wiring to all batteries?
Any busbars?
No washers between some plugs and busbars?

There is 15' of 2/0 wire between the Inverters and the Buss Bar.
Before I added the 4th EG4, All batteries were connected to the buss bar with 36" 4 ga wire and i had observed this same issue.
I have since bought the 4th and installed the 4 and Rebel #1 into the Signature Solar EG4 Rack. This Rack (500 amps) is connected to the Buss Bar with 12' of 2/0 wire. I will get some pics shortly

 

[yachtdr22]

As these are all 48V/16S 100AH packs, that makes it a lot simpler... get's trickier with different sized packs in a bank, it's OK just needs more math...

Unlike the old FLA days, adding LFP to a bank is NOT an issue, so not much to worry about UNLESS you have a Weak Pack that does not get to full charge parity with the others... That can actually draw down a full bank to the lowest point due to the higher voltage packs will attempt to backcharge. That has to be pretty serious though... ie a pack with 1 cell that won;t go above say 3.200V that will pull that pack down and subsequently the bank. This si observable & repeatable.

The USER Profile is the most flexible because you can set "You specific use case settings" and not getting canned with a generic profile.
Suggested profile which will work with ALL Packs without requiring BMS to Inverter connectivity.... User Profle can still be used when connected but tweakages are needed. ALSO a GOTCHA ! If the EG4's are connected but not the Rebel Packs then problems will arise as the EG4's know nothing about their companions.

All equipment MUST BE Voltage Corrected & Calibrated (VERY IMPORTANT)
Divide Values X2 for 12V. Multiply X2 for 48V.
Bulk - Absorb: 55.2V (3.45vpc) Absorb Timer set to 45 minutes (some call Absorb Boost) *Absorb rarely runs the full 45mins because of EndAmps
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:*1) (** Allows for full Saturation at set Float Voltage)
(*1): End Amps is calculated IE: (100AH X 0.05 = 5A or 280AH X 0.05 = 14A.)
EndAmps = TailCurrent (depends on vendor)
Coulumbic Efficiency / Battery Status Meter Efficiency for LFP = 99%.

This gets the bank charged to full with high amps (Constant Voltage / Constant Current) and then float (Constant Voltage / Variable Current) tops off so the cells are at 3.47Vpc.
* Do Not forget to adjust for Voltage Offsets between Actual Voltage @ Battery Terminal & at Solar Controller.

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.

Do note that every Lug, Terminal, Fuse/Breaker, switch etc adds resistance to the cabling and subsequently voltage losses. While no single item is large, collectively it adds up FAST ! Be Certain that your Solar Charger is CORRECTED / Offset Compensated. If the SCC thinks it is charging at 55.2V but with losses the Batt Terminals read 55.0 you'll never get truly charged. ALSO on the Inverter, the CUT OFF LOW VOLTAGE MUST BE ACCURATE, you do not want it to shut off early or late... Again the Voltage @ Batt Terminals RULES, so correct for even the slightest difference. NB: It is best to use at least a 2 Decimal Point Accurate DVOM/DMM

UNLIKE LEAD ACID - LFP IS Millivolt & Milliohm sensitive.

Lead Acid was chosen on the Sol-Ark as none of the BMS's go to it. I would LOVE to come up with some way that all the batteries could talk to the SA and be properly managed.
The Sol-Ark Settings are;
Battery Capacity(0-9999Ah) - 900
Max A Charge(0~275A) - 112
Max A Discharge(0~275A) - 275
Batt Empty V(41-63V) - 47
Batt Resistance(0~200mΩ) - 7
Batt charging efficiency(0~100%) - 99
Batt Shutdown %(0-100%) - 2
Batt Low %(0-100%) - 5
Batt Restart(0-100%) - 15
Float V(38-61V) - 55..9
Absorption V(38-61V) - 56.4

 

[yachtdr22]

As these are all 48V/16S 100AH packs, that makes it a lot simpler... get's trickier with different sized packs in a bank, it's OK just needs more math...

Unlike the old FLA days, adding LFP to a bank is NOT an issue, so not much to worry about UNLESS you have a Weak Pack that does not get to full charge parity with the others... That can actually draw down a full bank to the lowest point due to the higher voltage packs will attempt to backcharge. That has to be pretty serious though... ie a pack with 1 cell that won;t go above say 3.200V that will pull that pack down and subsequently the bank. This si observable & repeatable.

The USER Profile is the most flexible because you can set "You specific use case settings" and not getting canned with a generic profile.
Suggested profile which will work with ALL Packs without requiring BMS to Inverter connectivity.... User Profle can still be used when connected but tweakages are needed. ALSO a GOTCHA ! If the EG4's are connected but not the Rebel Packs then problems will arise as the EG4's know nothing about their companions.

All equipment MUST BE Voltage Corrected & Calibrated (VERY IMPORTANT)
Divide Values X2 for 12V. Multiply X2 for 48V.
Bulk - Absorb: 55.2V (3.45vpc) Absorb Timer set to 45 minutes (some call Absorb Boost) *Absorb rarely runs the full 45mins because of EndAmps
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:*1) (** Allows for full Saturation at set Float Voltage)
(*1): End Amps is calculated IE: (100AH X 0.05 = 5A or 280AH X 0.05 = 14A.)
EndAmps = TailCurrent (depends on vendor)
Coulumbic Efficiency / Battery Status Meter Efficiency for LFP = 99%.

This gets the bank charged to full with high amps (Constant Voltage / Constant Current) and then float (Constant Voltage / Variable Current) tops off so the cells are at 3.47Vpc.
* Do Not forget to adjust for Voltage Offsets between Actual Voltage @ Battery Terminal & at Solar Controller.

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.

Do note that every Lug, Terminal, Fuse/Breaker, switch etc adds resistance to the cabling and subsequently voltage losses. While no single item is large, collectively it adds up FAST ! Be Certain that your Solar Charger is CORRECTED / Offset Compensated. If the SCC thinks it is charging at 55.2V but with losses the Batt Terminals read 55.0 you'll never get truly charged. ALSO on the Inverter, the CUT OFF LOW VOLTAGE MUST BE ACCURATE, you do not want it to shut off early or late... Again the Voltage @ Batt Terminals RULES, so correct for even the slightest difference. NB: It is best to use at least a 2 Decimal Point Accurate DVOM/DMM

UNLIKE LEAD ACID - LFP IS Millivolt & Milliohm sensitive.

Batteries:
When the batteries arrived from ReBel they would not work.
The BMS Settings were all wrong and needed to be adjusted.
The EG4's are as is.
The ReBel batteries have the JBD-48V-100A-BMS-SP25S003 BMS

OverV - 3.7
OVR - 3.35
OVRD - 2.0s
UnderV - 2.5
UVR - 2.875
URD - 2s
PackOV - 58.4
POVR - 53.6
POVD - 2.0s
PackUV - 40.0
PUVR - 46.0
PUVD - 2s
ChargeOT - 65.0c
COTR - 55.0c
COTD - 2.0s
ChargeUT - -2.0c
CUTR - 5.0c
CUTD - 2s
DischargeOT - 75.0c
DOTR - 70.0c
DOTD - 2s
DischargeUT - -10.0c
DUTR - 0.0c
DUTD - 2.0s
ChargeOC - 100.0a
COCR - 32.0s
COCD - 10s
DischargeOC - -100.0a
DOCR - 32.0s
DOCD - 10s
Galv Resistance - 0.1mR
HardwareOCP - 330.0a
HOCPD - 640.0mS
HSCP - 670.0a
HSCPD - 400uS
HOVP - 3.9v
HOVPD - 8.0s
HUVP - 2.3v
HUVPD - 8.0s
Sort-Circuit PRD - 32s
Balanced Turn-On V - 3.4v
Balance Precision - 0.015v
Mos Control Time - 30s
Normal Cap - 100ah
Cycle Cap - 100ah
Single Full Volt - 3.5v
Single Cut-Off Volt - 2.94
80% - 3.4v
60% - 3.2v
40% - 3.1v
20% - 3.0v
Self Disc - 0.2%