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He good news is @TaliaB has been discharge and he is busy recharging hopefully to 100% SOC on a family farm.
His oxygen levels still need to recover and could take a while.
Thanks for the support on behalf of our friend.

So far yes. I have not seen a spike in the charging from solar since. At the same time, the SOC has not dropped to 51% since the initial event.

It subjectively appears that the battery appears to be perfoming better - the yard stick being the SOC when the MPPT switches of and then when it switches the following morning. There are many variables overnight. This also does not exclude lifestyle changes to try and ensure that when the MPPT switches of, the SOC is 100%. I am comfortable with an 80% SOC at about 06:00.
Pre‑firmware (01/05/2026 → 01/06/2026, 32 days)
Avg SOC at First (morning): 72.8%
Avg SOC at Last (evening): 89.0%
Post‑firmware (02/06/2026 → 16/06/2026, 15 days)
Avg SOC at First (morning): 82.0%
Avg SOC at Last (evening): 92.0%
Delta (Post − Pre):
Morning SOC: +9.2 percentage points
Evening SOC: +3.0 percentage points
The chart below does not contain enough data yet. The blue line is when the MPPT is "Active" and red is Off.

May I say "I rest my case". It's quite obvious that the insulated box idea that you appear to dislike is in fact working very well, with diminishing standard deviations giving an ample statistical confirmation of this.
And you sir, lack manners.
I'm sharing rather detailed, and well presented empirical data, with the hope that it might be of interest to fellow Forum members. I am NOT presenting a dissertation for a PHD - if I did, you can be assured that it would have contained more than enough science. If you really want more "science" I will be willing to do a really detailed study for you over the next year (at least, to cover variables such as changing seasons), but then you will have to pay me my professional fee - and I'm not cheap 🤑
So, let's rather not quibble about this any further, and agree to disagree on everything...

@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

My twingo ev starts reducing charging power already at 60%.... for example under 50% it charges full 22kW, above 60 it reduces already around 16kW, at 80% it is around 12kW and at 90% it is already below 10! and so on...

Never seen that. My EV starts tapering off at 85% - but this corresponds with reaching the target charge voltage, and entering CV phase (where current tapers of natually).
Most lithium chemistries hit this point at around 85%.
None of the BMSs I have used have tapered off current for any other reason, but I suppose it is possible (although I have also not found any cell manufacturer who recommends anything but straight CC-CV charge profiles).

@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

@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 agree with @Steve87 all good.

Honestly it doesn't get better than this. Anything else will be a new product from the Factory. Lowest cell at 3.47 is very close to a full cell.
This type of top float balancing can even be done once a week. In the high end Commercial installations these batteries carry out 2 Cycles a day due to 2 peaks (morning and evening) and once a week keeps them in good shape.

What you’re seeing is mainly due to the steep voltage curve near full charge, where even very small SOC differences between cells translate into noticeable voltage differences while current is still flowing. That happens regardless of the brand or pack size.
The absence of an active balancer can make it a bit more visible or slower to settle, since passive balancing only trims the higher cells gradually. But in your case, since the delta collapses quickly once charging stops and everything stays aligned under load, it’s still well within normal behaviour and not something that indicates a problem.

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.

You can always try to use voltage settings for a while and charge the battery to 55.5 for a week and then slowly every week up it by a 0.1v.
I have done this for one a set of batteries before with a pacebms and it balanced fine.

But you need to disable coms and set float and charge voltage the same

My experience has also been in not too hot conditions the inverter type will use less power due to lower work load. It is a major plus to have no surge for starting and kinder to your battery and inverter.
Inverter type just is a better all round choice.

MTBF is a statistical measure, not a lifespan. It represents the average failure rate of a population, not how long a specific unit will last.
Putting two inverters in parallel does not halve their MTBF. Each unit still has the same failure rate, but system reliability improves because both units must fail before total loss occurs.
The real risk in parallel systems is not MTBF, but common-mode failures such as surges, battery faults, or wiring issues that can take out both units simultaneously.
In practice inverter failures are rarely random MTBF events. Most failures we see in the field are due to surges, heat, battery issues or installation faults. Running two inverters in parallel does improve resilience against small component failures like fans or relays, allowing the system to continue operating at reduced capacity. However, it does not protect against common-mode failures such as lightning, grid surges or battery faults, where both units are typically affected simultaneously.
So the real trade-off is not MTBF, but complexity vs partial redundancy. Proper surge protection, earthing and installation quality will have a far bigger impact on system reliability than choosing between 1×10kW or 2×5kW.

He has a old one and a brand new one then. Would that not make them fail far apart of they do fail?

Also lets say they are the same age. If they do fail even a just a week or a few days apart you can get a replacement fast while not being 100% down?
Just a few days to ship a new unit to get you up again

I think that the answer to this is possibly quite a lot simpler than most of you are looking for
I suspect that the inverter is just getting to hot and is therefore limiting the amount of solar power coming in
I find this quite often in inverters that don't have active cooling or inadequate ventilation

My 2 cents:
The graph suggests that the PV output is being limited by the inverter’s MPPT or system settings, rather than the solar array reaching its natural maximum. The flat plateau indicates the inverter is capping the power, not that the array cannot produce more.
It would be worth investigating inverter-side limits, such as battery charge current limits or other configuration settings that could be restricting PV production.
For comparison, here is a VRM graph from a system where the array actually reaches its production ceiling. The array consists of 6 × 460 W panels (2760 W theoretical), yet the maximum observed production is around 2000 W, which reflects real-world conditions rather than an inverter-imposed limit.

In this case the shape of the op's curve suggests inverter limitation rather than array limitation.

All speculation. First check maybe if you've got a battery charge rate limit set to around 70A. The solar panels will only produce what the battery system demands.
Beyond that, I'm assuming your 7 panels are installed on one MPPT. Could obviously be wrong, I don't know. I'm wondering whether that inverter has set a limit on the power that one MPPT can produce. Considering the low start-up Voltage on your inverter, I'd try to spread the workload and experiment with connecting the panels in strings of 4 and 3 onto each MPPT and see if it makes a difference at mid-day. Three panels are obviously borderline on the low Voltage end, but the point would be to test if you can go above 3500W in total at noon when the Voltage is expected to be sufficient, and then you could consider based on what you see, whether to return to 7 in series, or add one panel to go 4+4.

As I once struggled with resetting password for WatchPower app & voltronic inverter logger. I tried a lot of stuff and finally got helped by sending a WhatsApp to this company that has a direct link to Voltronic in Taiwan. I attached a screenshot with the number to send W number on the logger for reset so you can register again.

The real test is during winter with those extra long shadows and lower irradiation that can reduce PV output to less than 50% of the summer value. I do see you are quite a bit away from the equator at 33.5 degrees north.

Once an MPPT is active, operating near its minimum tracking voltage does not materially reduce energy harvest.
By contrast, placing panels with different shading profiles on the same MPPT forces current compromise and causes large, unavoidable energy losses.
Therefore, two independent strings that each barely satisfy the MPPT voltage requirement will consistently harvest more energy than a single higher-voltage string that is partially shaded. If a string repeatedly drops below MPPT start voltage, it will cycle on/off and lose energy. But if it stays above the threshold, even marginally, it operates normally.

This would be the better option for the 7 panels. As the inverter has 2 MPPT's the 3 panels might at times not start the MPPT due to the requirement of a 130V start up. It does seem as if the roof allows the new 3 panels to be increased to 4. This I belief would allow them to work well and will be money well spend.

Bypass diodes only protect cell groups inside a single panel. They do not isolate an entire shaded panel from a string.
In your case: Morning: The new panels are shaded they limit string current Midday: All panels clear OK .Afternoon: The old panels shade first same problem, reversed. Because a series string must pass the same current through every panel, the weakest (shaded) panel dictates the operating point. The MPPT can only track one compromise point, not two different irradiance profiles.
Put the 2 strings on diffrent Mppt's. Most systems gain more kWh/day by separating shaded arrays, even if each string runs at a lower voltage. Just ensure adequate start up voltage on the 3 panel string .

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%