String Performance

Hi all - delighted to discover this community this evening. Have spent the last several hours reading and trying to learn.

Wondering whether I have a string problem?

We're running 17 x 405W (so peak 6885W) Mono PERC panels (with 17 x Tigo TS4 PV optimisers), 2 x GivEnergy Gen2 9.5kWh batteries and 2 x GIV AC3.0 inverters.

The inverter info in my portal yesterday (glorious sunshine all day, if a tad warm) is showing a peak generation of 4170W from string 1 yesterday in one battery, and peak generation of 7W from string 1 in the other battery.

This data is consistent from each battery since installation, i.e. high numbers in one battery, negligible in the other.

What is the usual presentation of data from a two string set-up (which is what we have here)? Does the portal normally amalgamate it under one string, even though there are columns for data from two strings?

I'd say we're running at about 60 - 65% expected output since installation (anticipating ca 4kWh per annum from an estimated 6.3kWh). For referenced, we generated 20kW yesterday, when Solcast API was predicting 32kW.

Thanks!

RichWilsher2022 Hi and welcome to the GE community forum.
I am a relative newbie myself, but like you I've been reading a lot and learning although the arcane mysteries of system design are still relative opaque.
I don't know why your system was set up as you describe. Two batteries is probably a good idea, but I am not sure you needed two inverters. I have 24 x 425W Perlite panels (nominal 10200W) in two 12-panel strings but they both feed into one GE Gen 3 3.6 inverter and one 9.5kWh battery. The inverter can deliver 5kW AC and at peak generation an additional 3600W to charge the battery.
Yesterday, which means Monday Sept 4th in my case; I am not sure which "yesterday" you are referring to, we generated 34.5kWh compared with a Solcast forecast (which I generally ignore completely other than as a guide to good or bad days) of 53kWh. The generated power was roughly 16kWh from the East array and 18kWh from the West array.
Since I don't have separate inverters I am not sure about the reporting in your case, but yours sounds wrong to me if one string is only reporting 7W peak. But do GE report the two inverters separately? PPV1 and PPV2 should both have been roughly the same like mine and if we're looking pro rata on system power you'd have generated about 70% of my system assuming East/West orientation, or about 24kWh split roughly evenly. My peaks on PV1 and PV2 were 3288 and 3102.
How long has the system been installed? Suggest you talk to your installer. Maybe they haven't set the optimisers up properly? I don't have any, so can't help there. But it is also quite likely to be some glitch in the way GE collect data when two inverters are involved. Other people on here have a two-inverter system so they may be able to help more.

If you have 2 inverters I presume only 1 string has been used on each inverter. Therefore you'll need to look at each inverter individually. You should see two inverters in the app/portal.

anthonypar The two inverters mentioned by the OP are AC inverters. That means ther's another inverter somewhere that is actually managing the panels and creating the DC-AC inversion. The will be 2 AC inverters to will enable 6kw of charge and discharge (albeit the charge to seperat batteries. I think in old parlance this would be a GE 'plant' system.

ThePud Just reading your post and wondered how you get 5kw AC output from a 3.6kw inverter? Am I missing something?

TimHutchings The GEN 3 inverters can do this. The 3.6 limit is for charge/discharge of the battery.

cluelesscris ok if you say so, but the gen3 3.6kw inverter spec says max AC output is 3.6kw AC, not the 5kw AC output mentioned in the post. I know the battery output is 3.6 kw on a gen2 9.5kw battery. Just wonder why the 3.6kw inverter is called 3.6kw if it can output 5kw AC. Thought that's what the 5kw inverter did! I have a 5kw inverter and it can only output 5kw ac.

cluelesscris , can you share a screenshot of your inverter outputting 5kw AC?

dragos.balaban Yes, scrub that. I was looking at the wrong datasheet. Besides which the OP says he has AC3 which is capped at 3.0kw. I wonder, if he does have AC3's, the 5kw he is seeing is through the clamp(s) on the output from some other inverter.

cluelesscris The confusion is partly my fault because it turns out that my installer gave me a datasheet for a Gen 3 3.6 despite having installed a Gen 3 5 Hybrid, and I assumed that the 3.6 referred to the DC battery charge. In fact what I have is a Gen 3 5kW Hybrid that can also - I think it is "also" but the datasheet isn't completely clear - output 3600W DC to charge the battery. So at least in theory it can output 8600W total, generation permitting. Correct me if I am wrong.

ThePud Correct me if I am wrong.

You're wrong 🙂

The Gen 2/3 hybrids both have a max DC power limit of 7.5KW according to the datasheets, so a 5KW inverter could for example put 3.6 to battery and 3.9 to grid simultaneously. Gen 1 figure is lower.

RichWilsher2022 We're running 17 x 405W (so peak 6885W) Mono PERC panels (with 17 x Tigo TS4 PV optimisers), 2 x GivEnergy Gen2 9.5kWh batteries and 2 x GIV AC3.0 inverters.

He has AC inverters installed, NOT Hybrid.

Therefore as has been already stated he will have another inverter that handles the Solar PV duties.

The GE AC inverters are AC coupled they ONLY handle the charge/discharge of the batteries.

By having 2 x AC inverters he has a higher AC output from them 2 x 3kw (6kw total) for the house load.

RichWilsher2022 In answer to your original query.
As you have 2 separate AC Coupled GE Inverters you will only be able to see the data from each inverter separately.
If you need to look at how each PV String is performing then you need to look at the data for your Solar PV Inverter (this is NOT the GE AC Coupled inverters).

I don't have an AC coupled myself so can't really comment on what data you see. So will leave that to others.

Hi, another newbie here. I have a similar issue to the OP, however in my case I have 2 strings on one inverter, Gen2 hybrid. Yesterday (Mon 4th Sept '23) @9am, full sun, my inverter was reporting 200w input. I tapped around in the app and it suddenly jumped to 1200w.

I asked the question on the FB page last night and was told that if it happens again to restart the inverter from the on-line portal.

This morning the same thing happened, so at 7:54 I restarted my inverter and the input when from 19w to 600w.

During the issue, both strings where showing 0A and voltage close to 220v. After the issue 6A 180v

Is this a known issue and is there a fix coming?

rjp Ok I am grateful for the correction, but the data sheet I have only mentions 7.5kW as a limit (per string) on the input side, and my installer has just confirmed my original suggestion, so I am more confused than ever.

ThePud There have been plenty of posts about the capability of various hybrid inverters. Suffice it to say that the gen1 HY5 (given surplus PV), is good for 2.5kW DC-DC (battery charge) concurrent with 5kW DC-AC (house load/export). The later gens are good for more DC-DC..

ThePud I am more confused than ever

Apologies. You're now not the only one! There are two different Gen 2 datasheets around - the latest one say "7.5KW per string", the original one just says: Gen 2 3.6 : 4700W, Gen2 5.0 : 6500W - no mention of 'per string'.

I have a gen 2 3.6 with ~4.7KW of panels on a single string. With the pre-909 firmware, the max power was always split 50-50 between strings, and our panel output was being clipped at ~3kW. Later firmware fixed this so we can use the full power on one string. Based on this I think the latest datasheets are very likely wrong.

rjp My guess is that we've probably exhausted this but here is the data sheet for the hybrid gen 3 inverter I actually have on the wall.