What does low voltage but high current mean?

[WhatSun?]

I have two identical strings, both connected in series, one averages 260-280 volts which is within the PV panel specs and the other is only giving me 170-190 volts which is way below where i think it should be, none of the two have any shadows on them.
String with lower voltage will always show higher current with lower voltage while the higher voltage string always shows higher/normal voltage and lower current.

But if i restart the inverter then both strings will show almost the same voltage and current for the rest of the day.

What could be causing this?

 

[Brucey]

I have two identical strings, both connected in series, one averages 260-280 volts which is within the PV panel specs and the other is only giving me 170-190 volts which is way below where i think it should be, none of the two have any shadows on them.
String with lower voltage will always show higher current with lower voltage while the higher voltage string always shows higher/normal voltage and lower current.

But if i restart the inverter then both strings will show almost the same voltage and current for the rest of the day.

What could be causing this?

Is it an eg4 aio by any chance?

 

[WhatSun?]

Is it an eg4 aio by any chance?

Its a Canadian Solar On Grid inverter with PV panels of the same brand.

 

[Detritalgeo]

Same light exposure? I have a small property with 2 strings and a bunch of trees in the area so shading at different times is challenging but what I notice is that the string generating more current will have a lower voltage as the draw from the MPPT drags it down slightly. Maybe the higher voltage string has a weak point? Or a connection with too much resistance ?

 

[RCinFLA]

I have two identical strings, both connected in series.
String with lower voltage will always show higher current.

Your statement does not make sense. Two strings in series will have the same current.

Sounds like what you really mean is you have two separate identical strings to separate MPPT inputs on a AIO inverter and they are not finding the same MPPT point until you reset the AIO inverter.

That would be an inverter MPPT controller problem. Likely they are getting confused in the morning when sun starts to come up and the MPPT controller collapses during startup attempts when illumination current is still low as the sun rises.

You can have separate series arrays that under reasonable sun illumination produce the same Vmp and Imp but the series connected panels have slightly different shunt leakage current.

When sun illumination is reasonably normal, the difference in shunt leakage is insignificant. But in the early morning when the illumination is low the difference in panel shunt leakage current is significant in relation to the low sun illumination current generated. This causes a totally different Vmp search result.

It sounds like the AIO MPPT algorithm gets stuck on the initial early morning search result and does not have the smarts to refresh its initial early morning MPPT search result until you manually kick it with a new reset.