String 2 no power ?

So up until about 4 weeks ago system seemed to be running well.

There are two strings:-
1) 5 x Jinko Tiger Neo N-type 54HL4R-B 420-440 Watt Panels South Facing
2) 4 x Jinko Tiger Neo N-type 54HL4R-B 420-440 Watt Panels West Facing

These are coupled to Hybrid Inverter 3.6 Gen 3 with Battery Giv-Bat 9.5 Gen 2.

String 2 now seems to been struggling, Voltage is around 145Volts. Now when this was installed they set the MPPT start voltage to 120V. So i'm not sure why it is not generating any power.....

Anybody have anything similar ?

4 of those panels, the maximum power voltage is not much over the 120v startup even VOC isn't exceeding 160. When they were working 'better' what was the voltage recorded as?

This is back in June and you can see String 2 kick in at 2024-06-01 07:16:47

DATE V1 V2 A1 A1 W1 W2 TPV
2024-06-01 07:47:29 169.2 148.1 2 0 342 3 345
2024-06-01 07:42:22 170.2 130.8 2.2 1.5 383 200 583
2024-06-01 07:37:15 171.9 127.7 2.1 1.6 361 199 560
2024-06-01 07:32:08 165.3 127.7 1.6 1.3 267 177 444
2024-06-01 07:27:01 174.5 141.3 1.9 1.2 351 106 457
2024-06-01 07:21:54 175 134.8 1.8 1.5 322 205 527
2024-06-01 07:16:47 173.1 125.9 2.1 1.8 371 234 605
2024-06-01 07:11:40 173.2 148.5 1.7 0 299 2 301
2024-06-01 07:06:33 162.5 147.4 1 0 170 2 172
2024-06-01 07:01:26 162.7 146.8 0.8 0 145 2 147

but at 7:47 the volts were back up to 148, amps down to 0 and power at 3 so it suggests there's not enough voltage maintained when it ups the amps to provide power to keep it going. Obviously that's on west facing panels so you wouldn't really expect much from them at 7am

This later in the day, you can the String 2 oscillating
2024-06-01 14:36:52 157.8 129.7 3.9 3.7 620 461 1081
2024-06-01 14:31:45 160.1 138.4 5.6 4.6 903 652 1555
2024-06-01 14:26:38 171.2 145.9 1.7 0 316 2 318
2024-06-01 14:21:31 157.8 140.2 14.3 10.2 2293 1439 3732
2024-06-01 14:16:24 154.7 143.4 5 0 780 2 782
2024-06-01 14:11:17 154.3 125 14.8 15 2295 1872 4167
2024-06-01 14:06:10 160.6 145.9 5.2 0 796 2 798
2024-06-01 14:01:03 165.1 136.7 9 7.6 1552 1051 2603
2024-06-01 13:55:56 170 137.4 11.1 11.2 1949 1583 3532
2024-06-01 13:50:48 155.9 127 4.9 4.8 765 616 1381

Tabulous Despite cloudless days this week, my solar generation has been a bit lower than it was earlier in the year - 6.4kWp system was outputting around 5kW. [I monitor this fairly closely to limit clipping.]

I'm assuming it's temperature-related - warm panels produce less power, and it's much warmer recently. I could probably look up charts and calculate the effect, but...

So I wonder if, in your case, temperature has risen enough that the panels are now borderline on reaching minimum voltage ?

Which firmware are you running ? Release notes for 308 talk about "Optimise PV MPPT Logic" - not sure if that's a euphamism for fixing problems after reducing minimum voltage.

I did see that.....

Inverter Firmware Version
D0.393-A0.393
Battery Firmware Version
3009

But I've been reluctant to push the button lol

So I wonder if, in your case, temperature has risen enough that the panels are now borderline on reaching minimum voltage ?

I think this is playing a part....... 100%

DD
I think I've got a similar situation on my east/ west arrays. For about the last 4-5 days pretty much no generation, whereas on my south facing they are chugging along fine.

Can someone provide a little more info on this comment as i'm not that electrically savvy:
"So I wonder if, in your case, temperature has risen enough that the panels are now borderline on reaching minimum voltage ?"

Is there a recommendation to resolving this or at least improving the situation?

Thanks

NiallKilleen eg datasheet for those jinko panels is at https://theecosupermarket.co.uk/wp-content/uploads/2024/03/Datasheet-for-Jinko-Tiger-Neo-54HL4R-B.pdf

That shows that voltage for peak power is around 35V, but drops off to 80% at 75 degrees. So 4 panels at 75 degrees would only have a voltage of around 112V, which is below the minimum threshold for the inverter. But when it's cooler, you'd get 140V. (Panels are arrange in series, so the voltages add, but the current through them all must be the same. Which is why one one is shaded, the current through the whole set drops.)

I've noticed that on cloudy days, when the sun does come out, generated power is higher than on cloudless days - I'm guessing that the panels are cooler, and so are able to operate at higher power when they do see the sun. But on cloudless days, the panels get and remain hotter.

Not sure how to mitigate this. Fitting optimisers, perhaps: my understanding is that while they cannot increase the power from the panels, but they can adjust the voltage they present to the inverter. ie they might turn 10A at 30V into 8A at 37V. Maybe something like that, anyway ? (More importantly, they can patch up one shaded panel so that it doesn't drag the serial current down.)

just wondering if something like this would help

https://www.tradesparky.com/solarsparky/accessories/miscellaneous/tigo-ts4ro-retrofit-optimiser-frm-mount?affiliate=product_feed&utm_source=product_feed&utm_medium=product_feed&utm_campaign=product_feed&gad_source=1&gclid=Cj0KCQjwtsy1BhD7ARIsAHOi4xakKAG3aurLQrVRGho0dS7tz-bWk_utcE1Wi5wqQ-svxdMy75JGOK4aAvr2EALw_wcB

If the system worked before and now doesn't then its extremely unlikely to be anything other than a fault.

FWIW I have a 4 panel string and it worked fine (even in winter) when the inverter was set to 150V startup. It only requires one string to hit startup voltage, not both. Edit - in fact I have the same number of panels in each string as you do.

Tabulous A very quick search suggests that Tigos tend to reduce voltage in order to increase current? Which is the opposite of what's needed here, unfortunately.

But I'm probably wrong.

Vestas I would have thought both MPPT channels would be independent ?

Take today for instance, string two showing 148V but no power from it ?

Tabulous They're independent but the startup voltage is the inverter as a whole, not per string.

Edit - they can be independent or run as 1x2, default is independent.

So spoken to Givenergy, and they straight away said firmware was very old and what is shipped from the factory. They said setting MPPT start voltage to 120 would have no effect on this firmware, you need newer firmware. Anyways one update later and the second string seems to be working well again.

Tabulous So despite what you originally said, the system has never worked correctly until now?

Vestas That's right, the VOC was always high enough, but the high ambient temp, mean't lower VOC thus 2nd string started to not start.

Guys at Givenergy said that the invertor still had factory shipped firmware and thus the setting of 120V startup for MPPT channels will have had no effect.

After the update everything is now working very good.

This was the other day, you can see how well its tracking and also see the convergence between south and west facing strings.

Quiet funny, the drop off between 6pm and 7pm is shading due to a tree lol....