Start-up voltage

Can the start-up voltage on my gen 1 hybrid 3.6 be changed from 150v to a lower figure to aid generation on more marginal days?
Are there any negatives to doing this?
Thanks

I thought about this when I read the post 'G1 Hybrid PV MPPT string start voltage' earlier today. I then looked in the portal at my PV generation and on my system the chances of getting a watt or two of generation at that voltage level are so remote that I wouldn't bother (I've had 170v and 0 watts). I have 2 strings 8x405w and 13x405 so the voltage rises pretty quickly past 150v as the sun rises and 120v is well below the level of noticeable production.
If you only have 3 or 4 panels on a string then there could be generation at 120v. Have a look at your portal and see how much you are generating when the string voltage reaches 150v if it is only a few watts then I don't think changing the startup voltage will make any difference.

SJB Its not going to be worth changing unless you have short strings.

The PV panels on my shortest string (string 2) have open circuit maximum voltages of 42V but maximum power voltages of 34.7V.

4 x 34.7V = 138.8V

So with only 4 panels you can see that 150V startup is a bit high and that seemed to have the knock-on effect of not tracking correctly in some instances.

Basically if it was a clear day then string 2 ended up with noticeably lower current output than string 1 until some clouds passed over then current outputs would be the same.

Strings are immediately adjacent vertically so you'd expect the same current from each when in full sunlight.

Today was the first clear day from dawn to the point at which the PV array was in full sunlight so I got to see what happened in the HA graphs and string 2 tracks much better now.

Thanks for your comments.
I have 11 370w panels, two rows horizontally split 6 and 5 below.
Have checked the portal figures and the generation is negligable below 150v, the bottow row generation figure only 8 minutes behind the top row on startup.
We always want to tweek more out of our systems, so had to ask!

Why are they in two strings if they all face the same way? We have 11 on the same roof in one string.

Advised by installer to share input over the two strings.
Do others have a view on this?

DIG I suspect 11 on one string would hit the 2800W per string limit on your inverter and lead to clipping in good sunny weather.

I have two strings of 6 panels, one south and one west. Gen1 3.6kW inverter.
I've just had a look at my data from this morning and I had a watt on the south string at 7:43 this morning with the string voltage less than 80V. The inverter was alive as it is transforming the battery to power the house, which may make a difference.

I have this issue but my system (2 strings, 5 x east and 5x west) seems to stall, so I have to reboot inverter so make to produce anything when there is plenty of light...does anyone know if the 150 threshold before it will product could effect the opposite stings....i.e if sting 1 meets 150 but string 2 is below ? Givenergy have been useless and looking into this, they even swapped out the inverter ... Pretty poor system in my eyes unless it's summertime which masked issue

DGinUK What do you mean stall?

This is my strings from this morning. (I've tuned off total power on the screen grab)

Not sure how much you will see- but had a few watts from about 7:30 and then kicked in more from about 8:30 - then the sun probably came out from behind a neighbours tree just before 9.

So by stall I me
an you can see power generation and then it drops....untill inverter rebooted

Checking back on random dates my gen 1 HY3.6 inverter takes a much higher voltage than 120 before it shows Solar Generation is active. I have 2 strings of 7 panels, one east and one west. This morning for instance it reached 120v at 08:00am but did not start solar generation till 09:45 when voltage was around 250. Is this normal behaviour, do I need to get my start up voltage checked.

This is fairly normal, especially at this time of year. The solar panels are effectively constant current devices and they can generate a substantial voltage with little sunshine. But they need more sunshine to be able to generate any current.

I have a 4 panel string 1 and 6 panel string 2. In cloudy weather, of which we have had a lot recently, string 1 is spending hours between 140 and 150V and therefore not contributing, while string 2 is producing a few tens of whats, so tweeking the minimum down to 138 or 140 would help a bit. Is it possible to change this setting on the inverter?