GROWATT 3K Inverters not using PV Input in bright sun

[cknschneider]

I'm a novice solar enthusiast, but I have 2 new GROWATT 3k inverters, 32 240W solar panel (2 rows of 16 wired in parallel, the 2 rows in series).
Batteries are new lifepower 200 amp, and I have 5 in the rack.

It's almost noon, bright sun, batteries are at 74% and it's using grid to power the house and charge the batteries.
It's using most of the defaults, pgm 1 is set to SBU.
I've played around with every configuration that makes sense to me, but can't get it to use solar when it makes sense to.
You can see it connect occasionally at 50-60 volts but the voltage quickly drops back down to 26 and it disconnects from solar.
The only time it uses the solar consistently is early morning and late afternoon when the panels are mostly shaded.

Hoping someone can help - feeling like I just waited a lot of money ...needless to say, my wife is not happy :--------/

 

[Mattb4]

What is the solar panel ratings and what is your voltage measured from the solar panels at your Growatts without loads? I do not quite understand your two array configuration. Each inverter should have its own array. They should be wired such as to have sufficient voltage to run each inverter.

 

[cknschneider]

Thanks for your quick reply - I'm already relieved to have someone to talk to about this.
Panel rating is Vmpp= 31.1 Impp= 8.4 Watt=260. (thought they were 240)
I had 32 all in parallel hooked to an old style 24V inverter.
I knew that the GROWATTs would need more voltage, so I split them into two 24V arrays of 16 panels and wired the two arrays in series, hoping 48V would be enough, but in the sun they read 60V.
I have the PV going into a terminal block and it splits off there to the two inverters.
Here is the perplexing part - When I first turn the inverters on they read on the inverter display the same that I measure - 60V.
Still reading where the PV hooks in, the meter matches the display as it drops to 50, 40, 30, 26 then they disconnect.
Now, If I shut the system down and turn the PV switch to the inverters off - I measure a consistent 60V for as long as I hold the meter to the PV side connections. I've run the system for 2 months now and got a $120 electric bill, when the system should be powerful enough to never have to use the grid (I would think). We heat with wood. We don't have any large loads that we use for any significant amount of time. Any ideas? ..and thanks again for your time.

 

[Mattb4]

...
I have the PV going into a terminal block and it splits off there to the two inverters.
...

Two inverters sharing the same array is going to cause problems. Two SCC can share the same battery but not the same panels.

 

[Quattrohead]

What exact model of growatt inverter do you have or what is its maximum voltage input on the PV connections? I am very confused by your description as to how you've connected your panels to your inverter but either you are connecting too many in parallel or too many in series and over or under voltage for the PV input.

 

[cknschneider]

Growatt 3kW Stackable Off-Grid Inverter | SPF 3000TL LVM-24P​

I have 16 24V panels wired in parallel - the resulting two leads output 24V.
I have a second set of 16 24V panels wired in parallel - the resulting two leads output 24V.
I wire the two sets of 24V leads in series to produce a single resultant output of 48V

Max MPPT Voltage at PV input leads is 150V.

 

[Northernchateau]

Lets back the train up a min.
2s16p configuration
32 x 260 watts = 8,320 watts
2s configuration 31.1 volts x 2 = 62.2 volts
16p configuration 8.4 amps x 16 panels = 134.4 amps

If you are talking about a Growatt 3k 24v all in one, that unit is rated for max PV input of 2000 watts.
If you supplied 8 panels for Each unit ( not tied together) 260watts panels = 2080 watts.
If you have 2 units that's only 16 panels.
On top of that those units are rated for 80 amps PV input!

Do yourself a HUGE favor and after the sun goes down Disconnect those panels until you have a game plan.

 

[Northernchateau]

Growatt 3kW Stackable Off-Grid Inverter | SPF 3000TL LVM-24P​

I have 16 24V panels wired in parallel - the resulting two leads output 24V.
I have a second set of 16 24V panels wired in parallel - the resulting two leads output 24V.
I wire the two sets of 24V leads in series to produce a single resultant output of 48V

Max MPPT Voltage at PV input leads is 150V.

Let me give you 2 ways to connect you panels.
2s4p = 2080 watts , 31.1 x 2 = 62.2 volts 8.4 amps x 4 = 33.6 amps
or
3s3p = 2340 watts 31.1 x 3 = 93.3 volts 8.4 amps x 3 = 25.2 amps
that means your over paneling the unit by just over 15%
That unit will handle 145 max so you need to look at the label on the panels and see what the VOC is.

BTW you do not have 24 volt panels you have Panel rating is Vmpp= 31.1. Becareful mixing PV volts and amps with battery volts and amps.

 

[cknschneider]

Two inverters sharing the same array is going to cause problems. Two SCC can share the same battery but not the same panels.

Lets back the train up a min.
2s16p configuration
32 x 260 watts = 8,320 watts
2s configuration 31.1 volts x 2 = 62.2 volts
16p configuration 8.4 amps x 16 panels = 134.4 amps

If you are talking about a Growatt 3k 24v all in one, that unit is rated for max PV input of 2000 watts.
If you supplied 8 panels for Each unit ( not tied together) 260watts panels = 2080 watts.
If you have 2 units that's only 16 panels.
On top of that those units are rated for 80 amps PV input!

Do yourself a HUGE favor and after the sun goes down Disconnect those panels until you have a game plan.

Thanks very much - hopefully the inverters were protecting themselves from the overload and I didn't ruin them. I appreciate everyone'
s feedback - you guys are great.

 

[cknschneider]

Let me give you 2 ways to connect you panels.
2s4p = 2080 watts , 31.1 x 2 = 62.2 volts 8.4 amps x 4 = 33.6 amps
or
3s3p = 2340 watts 31.1 x 3 = 93.3 volts 8.4 amps x 3 = 25.2 amps
that means your over paneling the unit by just over 15%
That unit will handle 145 max so you need to look at the label on the panels and see what the VOC is.

Thanks for the options - much appreciated.

 

[Mattb4]

Thanks very much - hopefully the inverters were protecting themselves from the overload and I didn't ruin them. I appreciate everyone'
s feedback - you guys are great.

When you rewire make sure that each AIO has its own panel array.

 

[cknschneider]

When you rewire make sure that each AIO has its own panel array.

Will do - Thank you!

 

[Northernchateau]

Will do - Thank you!

Let me suggest you purchase 2 combiner boxes, one is for each Growatt and wire your system either 2s4p or 3s3p as shown in the pictures below.
The Growatt units can share the batteries but NOT the solar panels.

https://www.amazon.com/gp/product/B091CTWXB4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[Mattb4]

Once you get your system up and going all you need to do then is come up with a way to make use of the extra panels that you have. Certainly gives you expansion possibilities.

 

[cknschneider]

Thanks very much for the diagram - between you and Matt I'm already back in business. I'll follow your diagram and purchase the combiner box (thanks for the link) for the permanent fix. You'll both get a kick out of this - I have a shutoff on each group of 8 panels, so I started by shutting 16 panels off - still the inverters are not using solar and I know I have a lot of rewiring to get the separate feeds. I understand they can't share the PV, so I wondered if I could pull the feed to the secondary and just leave the solar on the primary. Before I did that I threw a few blankets over a third of the 16 panel array to cut back on the wattage and amps. I shut everything down, disconnected the PV from the secondary. Fired it back on and the primary connected instantly to PV at 60-63 volts - hasn't disconnected in the last few hours - woo-hoo! Thanks again for everything - I'm going to order everything I need to it right - right now. And as for the extra panels - I still have my old 8KW three thousand pound inverter and a dozen good lead-acid batteries. I'm thinking power the garage out back, install a water feature and light the property :--------)

 

[Northernchateau]

Thanks very much for the diagram - between you and Matt I'm already back in business. I'll follow your diagram and purchase the combiner box (thanks for the link) for the permanent fix. You'll both get a kick out of this - I have a shutoff on each group of 8 panels, so I started by shutting 16 panels off - still the inverters are not using solar and I know I have a lot of rewiring to get the separate feeds. I understand they can't share the PV, so I wondered if I could pull the feed to the secondary and just leave the solar on the primary. Before I did that I threw a few blankets over a third of the 16 panel array to cut back on the wattage and amps. I shut everything down, disconnected the PV from the secondary. Fired it back on and the primary connected instantly to PV at 60-63 volts - hasn't disconnected in the last few hours - woo-hoo! Thanks again for everything - I'm going to order everything I need to it right - right now. And as for the extra panels - I still have my old 8KW three thousand pound inverter and a dozen good lead-acid batteries. I'm thinking power the garage out back, install a water feature and light the property :--------)

Your very welcome. I don't like to see anyone have a fire or let the smoke out of electronics.
You have enough panels to add a 3rd Growatt / combiner box set-up.
If you have any question just ask and there is enough members on here to help point you in the right direction.