Good day we have a problem  we are used to connect solar panels in series of 2 but we done series of 3 monday and a problem came up the 5kva 4kw inverters only charge the batteries to 52V (series of 4 batteries)

And we cant get them to 56V our rated voltage that we set the inverter to the all cables are 16mm thick and we run 9 panels per inverter all the settings are correct to what we want but it only stays at 52V or drops to 50v 

Our solar gives out 68A and 120V and they are 330W solar panels

5 hours ago, Jg69 said:

we are used to connect solar panels in series of 2 but we done series of 3 monday and a problem came up the 5kva 4kw inverters only charge the batteries to 52V (series of 4 batteries)

So it sounds like you have an off-grid inverter, not a hybrid. It sounds like it's an older inverter (or more than one in parallel), with a 145 V max MPPT voltage. These solar charge controllers start power limiting at 130 V, and produce zero power at 145 V.

It also sounds like you recently upgraded your panels from a 2S configuration, to new panels in a 3S configuration; is that correct? A little more information in your posts would be helpful.

5 hours ago, Jg69 said:

And we cant get them to 56V our rated voltage that we set the inverter to the all cables are 16mm thick and we run 9 panels per inverter all the settings are correct to what we want but it only stays at 52V or drops to 50v 

Our solar gives out 68A and 120V and they are 330W solar panels

So it sounds like you have three inverters; 68 A x 120 V = 8160 W, and you say you have 9 330 W panels per inverter (so nominally just under 3 kW per inverter).

If Vmp is 120 V, then Voc will be a lot more, possibly exceeding 130 V where power will limit. Perhaps it is limiting power so much that the panels can't get started, lowering the panel voltage below the 130 V derating point.

Can you post some information about the panel voltage, and preferably also the panel power?

The other thing is that you could be suffering from the premature float bug. One solution would be to run patched firmware version 73.00e.

5 hours ago, Coulomb said:

So it sounds like you have an off-grid inverter, not a hybrid. It sounds like it's an older inverter (or more than one in parallel), with a 145 V max MPPT voltage. These solar charge controllers start power limiting at 130 V, and produce zero power at 145 V.

It also sounds like you recently upgraded your panels from a 2S configuration, to new panels in a 3S configuration; is that correct? A little more information in your posts would be helpful.

So it sounds like you have three inverters; 68 A x 120 V = 8160 W, and you say you have 9 330 W panels per inverter (so nominally just under 3 kW per inverter).

If Vmp is 120 V, then Voc will be a lot more, possibly exceeding 130 V where power will limit. Perhaps it is limiting power so much that the panels can't get started, lowering the panel voltage below the 130 V derating point.

Can you post some information about the panel voltage, and preferably also the panel power?

The other thing is that you could be suffering from the premature float bug. One solution would be to run patched firmware version 73.00e.

Its a off grid inverter that also can charge the batteries it has a built in mppt controller its a 2019 model name is scubart its exactly the same just like acer or 5 star  only a different colour

The inverters are in parralel each has 9 solar panels in series of 3.Yes the solar panels were on the roof for a year until we upgraded to building racks for them

The panels information is mpv:340W   voc:45.93v  vpm:40.1v  isc:8.86A

 

4 hours ago, Jg69 said:

Its a off grid inverter that also can charge the batteries it has a built in mppt controller its a 2019 model name is scubart its exactly the same just like acer or 5 star  only a different colour

Err, sorry. Schubarts are clones, not exactly the same as a Mecer at all. The ¢ symbol on the label instead of the Φ symbol (for "phase") is one of the giveaways. So who knows what is in there, and what quality of parts they used. Let's presume for now that they copied it properly, and it works the same as a real Voltronic Power inverter.

4 hours ago, Jg69 said:

The panels information is mpv:340W   voc:45.93v  vpm:40.1v  isc:8.86A

With a Voc of 45.93 V at 25°C, that's over 138 V, well past the 130 V derating point (again, assuming they copied that behaviour from the Axperts). You really should have wired them 2S; it sounds like that's how they were wired originally. It might be worth trying a single pair of panels, to see if it charges properly from a pair of panels wired 2S. If so, then wiring them all 2S is an option. Unfortunately, that means only 8 panels on 2 inverters, 10 on one, and one unused.

When winter comes around, on a frosty morning those panels will generate perhaps 147 V, which could damage the solar charge controller. In reality, it will probably survive.

It might be possible to re-flash the firmware to 73.00e even though it's a clone; this would at least overcome the premature float bug. But it might brick or damage the inverter.

Sorry; there are no easy answers for this situation.