Beat

On my 3 older LEOCH 48100TB the BMS calculates SOC by counting metered Ah in and out but neglect the internal losses. The result is their SOC readings are always to optimistic. When approaching full charge their BMS display 100% SOC while the batteries have not yet reached full charge voltage and continue charging. Therefor I prefer charge managing by the Inverter on the base of battery voltage without interference from the BMS via coms.

@TaliaB @Stefan Cornelissen @Steve87 @Beat
I’ve changed the requested charging voltage from the battery side to 56 volts. Since then, I’ve noticed an improvement. It appears that the BMS only balances the battery when there’s charging current, and the battery SOC isn’t 100% (maybe).

Now the delta dropped significantly

I have:

Its a LEOCH 48100-S. I have no coms and use inverter settings for bulk and float charge voltages according to specs of the battery manufacturer. According their recommendations the bulk charge remains for 1 hour to allow for balancing. However it looks like it has no effect. Averge refuses a guaranty claim by arguing that the pack still has full capacity according to specs.

I think you don't need an additional MPPT. Connect the west roof panels in parallel with the east roof panels. This will not overload the MPPT since the east and the west panels will never deliver full power at the same time. I have such a situation and write from experience. Condition is however that east and west panels are of the same type (same number of cells).

What you mention are protective parameters, not charge managing. If any those exceeds critical value by internal cause the BMS has the ability to disconnect itself from the terminals. If you have a bank of several battery packs there is no need to intervene with the inverter leaving the rest of the system functional.
What you need however is periodically monitoring of the packs. I do it with a RS485 bus connected to each pack and wired to a laptop in my office. You might also do it with WiFi.

Hi,
I do repairs on inverters for over 38 years
All types of inverters and and power electronics designs and is based in Mossel Bay area
0825526244

There is also another factor to be taken in account: the internal losses. As I observed on my LEOCH 48100TB packs the BMS counts and discounts Ah as metered to calculate SOC but neglects internal losses. The result is that when approaching full charge the BMS displays 100% SOC while the pack has not yet reached full charge voltage and is still charging. The difference between the displayed SOC and the true charge is the internal loss. If the battery is not fully charged as may happen on cloudy days the error of internal losses accumulate.
Note that my system manages charging only on the base of pack voltage.

I thought I’d share a real-world example of SOC drift on the upper end when a lithium battery is operated for long periods with shallow cycling and little to no absorption time, and how a full bottom–top recalibration resolves it.
System behaviour (last ±30 days):
Battery mostly cycled between ~80–100% SOC
No regular sustained absorption phase
Loads relatively light during the day
Result: gradual SOC drift upward, visible as the “compressed” upper band on the graph
This is typical behaviour for coulomb counting:
Small measurement errors accumulate
Without a true reference point (bottom or top), SOC slowly loses alignment with actual capacity
Corrective action taken:
Disabled MPPTs and grid charging
Set ESS minimum SOC to 0%
Discharged the battery under a controlled resistive load (~0.15C)
Allowed the BMS to reach low cut-off (~2% SOC) → bottom calibration
Left battery at rest
Re-enabled MPPTs and charged with no AC load
Allowed battery to reach 100% SOC with low tail current top calibration
Result (visible on the graph):
Clear SOC reset at the bottom (≈2%)
Clean reset again at 100%
SOC once again tracks voltage and real capacity correctly
Cell balance after charge: within ~10 mV
Temperatures uniform
Takeaway:
Lithium batteries do not need frequent deep cycling but occasional full bottom–top calibration is essential when: Cycling is shallow, absorption is rarely reached,SOC starts behaving “optimistically”
This isn’t a battery fault — it’s normal coulomb counter behaviour and easy to correct with a controlled recalibration cycle.
Graph attached shows the effect clearly.

No problem with your method at least you are on top of things by monotoring your system for deviations. Accessive heat in cables and safety devices is a telltale of high resistance at moderate to high battery current.
Voltage drop per meter (single conductor)

■ 25 mm² copper
Resistance: 0.00070 Ω/m
Voltage drop: 0.70 mV per amp per meter

■ 35 mm² copper
Resistance: 0.00050 Ω/m
Voltage drop: 0.50 mV per amp per meter

■ 50 mm² copper
Resistance: 0.00035 Ω/m
Voltage drop: 0.35 mV per amp per meter
Practical round-trip voltage drop (per meter of cable run)
Cable size mV/A/m (round trip)
25 mm² 1.40 mV/A/m
35 mm² 1.00 mV/A/m
50 mm² 0.70 mV/A/m
Installer rule-of-thumb (48 V systems)
Aim for <0.25–0.30 V total DC drop
That usually means:
≤1.5 m with 25 mm² @ 100 A
≤2 m with 35 mm² @ 150 A
≤2 m with 50 mm² @ 200 A
*Method: Use DMM on mV scale.
Measure total drop
Battery + to inverter +
Battery – to inverter –
Write both values down.
Work component by component:
Across positive fuse
Across positive breaker
Across positive cable sections
Across contactors / busbars
Repeat on negative side
Any point showing unusually high mV is your problem.
Cables (under load) 75% of inverter rating.
Excellent: <0.5%
Acceptable: <1%
Problematic: >1.5%

Giter batteries rack mounted have their batteries on their sides. I don't think this is a consideration.
It would be interesting to know if I am dreaming😀

Looks nice and need. How high can you go considering the wight of the packs?
There is one problem: In case you have to move one of the lover packs i.e. for inspection or maintenance, you would have to first take the packs above off. I prefer it this way:

Think about handling, i.e in case of requirement to move them. A 4.8kWh battery weights about 45kg. 2 persons can handle this but everything larger would require lifting devices. Better make up your storage needs with several handy units. Also in case of failure of one it would impact the system less.

Bingo! This is the first significant answer to the issue - thank you. I'll call the seller to provide me the link for the firmware update.

Shot in the dark here!! Maybe: Firmware bug: If the battery is relatively new and shows a very low SOH, it could be a known bug in the firmware. You may need to update the BMS firmware to a newer version, as some earlier versions had this problem.

I had same problem with my LEOCH 48100-TB packs. The setup with RS232 according to the manual didn't work. Finally the supplier came up with the solution:
Create a communication bus with all RS485 ports on the packs in parallel and connect with an RS485 adapter to the laptop. Also needed to change the software to PmodbusToos V1.20. Each pack must have a different address set by the dip switches. This way I can remote monitor every pack individually but not simultaneously. There is no master, all packs have same priority.

The real capacity of batteries
I started my system 5 years ago with 2 Battery packs of LEOCH 48100-TB. I gradually added another pack, a second 5kW inverter in parallel and PV panels. So far it worked to satisfaction. Last year I added 3 more battery packs. LEOCH had in the mean time come out with a new model that is the 48100-S. I connected all of them in parallel to one bank now theoretically 600Ah.
Pretty soon I noticed that the new 48100-S packs behaved different from the older TB48100-TB. First they draw higher currents than the older ones. I attributed this to a lower internal resistance due to improved manufacturing. However It was followed by a faster decrease of SOC when discharging. I noted differences of about 30% when the others were at 40%. It culminated in a low SOC shut off by the BMS while the other packs still run at 30%.
I checked the currents with my clamp on ammeter, they confirmed within reasonable tolerances. By analyzing this I came to the conclusion that these packs have in reality a significantly higher capacity than the older ones. The lower Ri, the higher currents, the contradiction between terminal voltage and SOC, everything pointed to that. I guessed to about 130Ah. However the BMS was set to only 100Ah full capacity. So at discharge the BMS discounts the metered Ah from 100Ah rather than from 130Ah and at a higher rate due to the higher currents. So I decided to change that setting in the BMS. But I had to wait for a moment when they are fully charged. Lately it happened. With PBmsTools I set each of them to a different value: 125, 130 and 135Ah in order to find out the best settings. After observing a couple of days it turned out that this was somewhat too much and I lowered Nr 4 and 5 to 120Ah and Nr 6 to 125Ah. That proved to be the real capacity and the SOC countdown is now within a few % the same as with the older packs. Note that this does not change the basic performance of the cells and packs. However it will prevent premature shut off by the BMS due to false low SOC readings. The wrong settings in the BMS falsify the SOC calculation. While at 100Ah capacity every Ah equals one % SOC whereas at 120Ah it takes 1.2Ah to make one % SOC.
Now hold on for a minute. I bought and paid 100Ah packs but got 120Ah and 125Ah - that's a bonus isn't it? It appears that when LEOCH redesigned the cells they achieved an increase in capacity within the same dimensions and wight. The difference between 120 and 125Ah is due to manufacturing tolerances.

The real capacity of batteries
I started my system 5 years ago with 2 Battery packs of LEOCH 48100-TB. I gradually added another pack, a second 5kW inverter in parallel and PV panels. So far it worked to satisfaction. Last year I added 3 more battery packs. LEOCH had in the mean time come out with a new model that is the 48100-S. I connected all of them in parallel to one bank now theoretically 600Ah.
Pretty soon I noticed that the new 48100-S packs behaved different from the older TB48100-TB. First they draw higher currents than the older ones. I attributed this to a lower internal resistance due to improved manufacturing. However It was followed by a faster decrease of SOC when discharging. I noted differences of about 30% when the others were at 40%. It culminated in a low SOC shut off by the BMS while the other packs still run at 30%.
I checked the currents with my clamp on ammeter, they confirmed within reasonable tolerances. By analyzing this I came to the conclusion that these packs have in reality a significantly higher capacity than the older ones. The lower Ri, the higher currents, the contradiction between terminal voltage and SOC, everything pointed to that. I guessed to about 130Ah. However the BMS was set to only 100Ah full capacity. So at discharge the BMS discounts the metered Ah from 100Ah rather than from 130Ah and at a higher rate due to the higher currents. So I decided to change that setting in the BMS. But I had to wait for a moment when they are fully charged. Lately it happened. With PBmsTools I set each of them to a different value: 125, 130 and 135Ah in order to find out the best settings. After observing a couple of days it turned out that this was somewhat too much and I lowered Nr 4 and 5 to 120Ah and Nr 6 to 125Ah. That proved to be the real capacity and the SOC countdown is now within a few % the same as with the older packs. Note that this does not change the basic performance of the cells and packs. However it will prevent premature shut off by the BMS due to false low SOC readings. The wrong settings in the BMS falsify the SOC calculation. While at 100Ah capacity every Ah equals one % SOC whereas at 120Ah it takes 1.2Ah to make one % SOC.
Now hold on for a minute. I bought and paid 100Ah packs but got 120Ah and 125Ah - that's a bonus isn't it? It appears that when LEOCH redesigned the cells they achieved an increase in capacity within the same dimensions and wight. The difference between 120 and 125Ah is due to manufacturing tolerances.

I had a similar issue with my newest purchased Leoch 48100-S pack. From the beginning cell 15 showed significantly higher voltage at charge and lower at discharge. This being a brand-new pack I contacted the official importer and seller, Averge, with a guarantee claim. But they didn't want to do anything about it. I asked to allow me to open the pack without voiding the guarantee to check the cells connections. They wrote me the permission and so I did. I tightened all M4 hexagon bolts of the cell bridges with a socket wrench. Some allowed up to a half turn. After reassembly and re-connection the issue with cell 15 no longer persists. It looks like all cells run the same voltage within a few mV. This proves to me that all cells are in good health.

I had a similar issue with my newest purchased Leoch 48100-S pack. From the beginning cell 15 showed significantly higher voltage at charge and lower at discharge. This being a brand-new pack I contacted the official importer and seller, Averge, with a guarantee claim. But they didn't want to do anything about it. I asked to allow me to open the pack without voiding the guarantee to check the cells connections. They wrote me the permission and so I did. I tightened all M4 hexagon bolts of the cell bridges with a socket wrench. Some allowed up to a half turn. After reassembly and re-connection the issue with cell 15 no longer persists. It looks like all cells run the same voltage within a few mV. This proves to me that all cells are in good health.

Despite your hesitation I would recommend paralleling another 5kW unit. The big advantage would be to have redundancy. If one unit fails, and they will one day, you still have the other one running in case of black out, even with reduced power capacity. I did it myself - it's not such a big deal.
Remember - you also would need to add some battery capacity.

My thoughts about it is: Get off grid and forget about exporting. Install an extra air conditioner in the inverter room. That would comfort the inverters and potentially extend their life. It would consume part of the produced energy but according to your writing anyhow overflows.

My thoughts about it is: Get off grid and forget about exporting. Install an extra air conditioner in the inverter room. That would comfort the inverters and potentially extend their life. It would consume part of the produced energy but according to your writing anyhow overflows.

My thoughts about it is: Get off grid and forget about exporting. Install an extra air conditioner in the inverter room. That would comfort the inverters and potentially extend their life. It would consume part of the produced energy but according to your writing anyhow overflows.

My thoughts about it is: Get off grid and forget about exporting. Install an extra air conditioner in the inverter room. That would comfort the inverters and potentially extend their life. It would consume part of the produced energy but according to your writing anyhow overflows.

I don't quite understand your logic. Voltage is the same in every language and the only information that does not lie. That's the reason why all inverters are programmed to manage charging on the base of battery voltage.
No, that's not the way it works. The BMS cannot regulate anything, it can only cut off the battery in case certain limits are exceeded. If the parameters are set correctly in the inverter there will never be over-voltage as long as there is no failure.