12 panels 405w each


What, me worry?
the difference in voltage between the combiner bow output and after the one thick cable was around 7 or 8 volts, but after I doubled the cable the difference reduced to 3V.
this was my combiner box when they were 3s4p. it is still the same box but now 2s6p.is there any problem in using like that modest box?
I am not a fan of the daisy chaining like that.

Each of those connections adds resistance and voltage drop. I would much prefer some type of bus bar.
Also, Do you have any fuses on each string?


What, me worry?
in addition, 381W of these 3818W were coming from the battery.
I don't read it like that.

The charger info says:

If you multiply 51.5V times the 74.1A you get 3816.15A. That is within rounding error of the displayed 3818W. I believe the 3818W is what is coming from solar.


What, me worry?
ok but could the inverter take from these 4860w more than 4000w?
No. The inverter would cap production at 4000W. However, since your production is less than that it is not capping the production.

today it was around 28 degrees celius.
28C is not very hot compared to the standard testing condition (25C). The panels will be hotter than ambient, but even then I would not think it would account for the reduction you are seeing.
is it realistic that panels give just 0.4A in short circuit where the sun light hits them from that angle ( around an hour before sunset)??
That is kinda a prety picture.....

With the Sun at such an angle to the panel, just about anything is possible..... but 400ma does seem low.