Inverter stuck voltage on PV string

[leon.davibe]

the other problem with these type of devices a lot of the programming is if else
and sometimes softeware bugs can get you stuck

example on the axpert off-grid types they have a float bug and if you spent x amount of time charging slow
it throws the inverter into float mode and keeps the battery voltage at lower voltage and charging slows down and that causes panels to idle

early on i had this just lifting the float voltage would pop it out of float mode and panels would ramp up

 

[DawieSwarts]

It is round about 270v pv1 and pv2 is both 8x 585w pannels facing north. It makes good power though. Was just worried something is not right. See pics of graphs for today.

 

[leon.davibe]

View attachment 1769433View attachment 1769434View attachment 1769435View attachment 1769436
It is round about 270v pv1 and pv2 is both 8x 585w pannels facing north. It makes good power though. Was just worried something is not right. See pics of graphs for today.

not a specialist just speculating based on what i have seen some inverters behave like

yea it does look odd that smooth looks like software stuck

is battery bumping up against max charge rate ever ?
no idea how the inverter software handles 2 strings
i would reckon it does change the voltage to match demand for charging + load if bumping up against max output or max charge rate of battery

and no idea if it would keep one at max output and fluctuating the other string or let both strings fluyctuate

 

[DawieSwarts]

Thanks for your input. The BMS does limit the charging to 90A for my 4 batteries. It is more than sufficient though. So in the morning it does limit the input to the battery. I don't mind that as it keeps everything cooler. I also think it is just a software thing. I'll leave it at that for now.

 

[name_less]

Hi Dawie, so I requested Deye to update my inverter firmware and enabled MPPT-multipoint scanning for the month. I suspect shadows was causing the issue.

The MPPT-multipoint scanning will do a whole voltage scan. It's not a permanent fix but at least doesn't lose out as much when the voltage is clipped or stuck.

However, I turned the featured off afterwards as there is a performance penalty when it does a scan every 30min. Especially when there is no shadow on the panels.

Since then I haven't had the issue again. I suspect I'll have an issue again in winter from the angle the sun and creating shadows.