pv combiner box

[the dosser]

i have 4 200w panels in series on my carport using a victron cc, charging a 24v battery bank, it works vey good
i have the same set up on the roof of my house except the pv string is going to a combiner box and then to the cc, it worked good for 4 days, for some reason it had low voltage today and and never got going, i checked the fuses , and the connections they are all good.
any help would be appreciated.

 

[cdsolar]

Check all wiring, then check voltage of each panel. You need a total of 24V + a bit to start charging. If your series string is disconnected somewhere, you won't get the required voltage.

If just one panel is bad, or not wired correctly, the whole series is disconnected.

Of course, there could be other issues, but start with this first with a multimeter.