My solar array shows good voltage, but won't power anything--Growatt SPF 3000TL LVM-ES

[rsi77]

Hello,
I'm just now setting up my off-grid system. I've connected my Growatt SPF 3000TL LVM-ES to my solar array and my battery bank. The battery bank is reading 52 volts, so it should be charging, but it's not. If I put a load on the output the battery powers the output, but the PV does not. But I have Solar Priority set for Prm01
Battery = 2X AmpereTime 24V 100AH in series
PV = 4 x 250W 37.6V nominal, Actual Volage ~33 volts each, input array voltage reading ~140V (shown on Growatt)
Prm01 = SOL
Prm19 = Prm20 = 58.4V
AC input is currently disconnected.

Any ideas why my array will not power the load, or charge the battery?
Thanks for any help offered.
Ron

 

[sunshine_eggo]

Recommend 01:SbU
19 is fine

58.4V is too high for LFP float. 20 should be 54.4V

Having 19 and 20 set to identical values can cause problems.

Battery specifications that state identical absorption and float voltages are wrong. You never want to float LFP above 3.40V/cell.

Recommend you change the settings. If that doesn't resolve,

Disconnect solar array.
Disconnect battery.
Reconnect battery.
Reconnect solar array.

 

[rsi77]

Thanks for the response.
I tried all of your suggestions, but have the same result: the battery won't charge even though it is below the voltage that should cause it to "request" a charge. And when I place a load on the output, even though the battery voltage drops to 49.9V, no PV kicks in.
It seems the system deems the PV as incapable of providing power. Or it's acting like it doesn't know it's there. Am I understanding the logic properly?
Does the system "test" the PV capability in any other way than the voltage reading at the PV input? I've never seen my array with a load, so I don't know how it acts.

 

[sunshine_eggo]

Sounds like you need to contact your supplier.

 

[DThames]

The solar charges the battery, don't specifically power the load. Look at your charging settings closely. 141v out of a 150v max input. Not sure at what voltage the system tries to protect itself but you might reduce your input volts and see if that changes anything. Your charging priority might be an issue. Something you can double check.

 

[rsi77]

The solar charges the battery, don't specifically power the load. Look at your charging settings closely. 141v out of a 150v max input. Not sure at what voltage the system tries to protect itself but you might reduce your input volts and see if that changes anything. Your charging priority might be an issue. Something you can double check.

The max input is 250V, so 141 should not be a problem. And in fact I originally had only 3 panels connected and had the same problem. I connected the 4th panel because I thought my input voltage might be too low.
The 3000 TL is supposed to supply power to the battery and/or the load--in fact it claims to be able to work without a battery, but not so sure about that.
Thanks for the suggestions anyway.

 

[rsi77]

Sounds like you need to contact your supplier.

I guess so, if there's not something I'm obviously doing wrong.

 

[sunshine_eggo]

I guess so, if there's not something I'm obviously doing wrong.

If you've changed the voltages and reset the unit as I described, I can't see anything.

 

[rsi77]

Problem solved! I called Watts 247 who originally sold me the inverter. They informed me that ~160 Voc was required for the system to start drawing power from the array. I added another panel which gave me 165Voc at this point in the day. The system started drawing power from the array. Under load the array dropped as low at 130Vmp, which is just above the 120Vmp spec. That explains why the 140Voc (4 panels) didn't work--it undoubtedly would drop below 120Vmp under load.
Now I can start to figure out what kind of loads this system can handle once I add all my panels to the equation. It's very cool to see the system working, and adjusting current to battery vs. current to load for various loads, (my load for testing is a heat gun with adjustable heat setting).

 

[DThames]

The max input is 250V, so 141 should not be a problem. And in fact I originally had only 3 panels connected and had the same problem. I connected the 4th panel because I thought my input voltage might be too low.
The 3000 TL is supposed to supply power to the battery and/or the load--in fact it claims to be able to work without a battery, but not so sure about that.
Thanks for the suggestions anyway.

I guess you have the 240v only version with the 250v input. I have the 120v version and (just checked) a 145v max input. I see you fixed it. Great.

 

[rsi77]

I guess you have the 240v only version with the 250v input. I have the 120v version and (just checked) a 145v max input. I see you fixed it. Great.

My version is the 120V version, it can do 240 volts only if run in parallel with another unit. It is the SPF 3000TL LVM-ES. I suspect you own another unit with similar, but not exact same part number, but with different specs. I guess on mine the input range is rather narrow. I will try to design my system with array Voc around 200, this should allow it to work most of the day, and still not go over the 250V max in very cold weather.

 

[sunshine_eggo]

Problem solved! I called Watts 247 who originally sold me the inverter. They informed me that ~160 Voc was required for the system to start drawing power from the array. I added another panel which gave me 165Voc at this point in the day. The system started drawing power from the array. Under load the array dropped as low at 130Vmp, which is just above the 120Vmp spec. That explains why the 140Voc (4 panels) didn't work--it undoubtedly would drop below 120Vmp under load.
Now I can start to figure out what kind of loads this system can handle once I add all my panels to the equation. It's very cool to see the system working, and adjusting current to battery vs. current to load for various loads, (my load for testing is a heat gun with adjustable heat setting).

Glad to hear it. Unfortunately, that's not clear in the specifications, and it's even implied that lower than 160V works as well.

 

[rsi77]

Glad to hear it. Unfortunately, that's not clear in the specifications, and it's even implied that lower than 160V works as well.

Agreed. The statement that the minimum voltage has to be higher than the battery voltage doesn't convey a minimum of 160 Voc.

 

[BoxTruckLife]

I'm looking at this model inverter into my conversion, and I'm a little concerned about the minimum VOC requirements.

I only have space for 3 panels (each at 48.96 VOC) on the roof. Will I have issues powering the load/charging the batteries on solar with this inverter?

 

[sunshine_eggo]

I'm looking at this model inverter into my conversion, and I'm a little concerned about the minimum VOC requirements.

I only have space for 3 panels (each at 48.96 VOC) on the roof. Will I have issues powering the load/charging the batteries on solar with this inverter?

I think your question was answered above:

Problem solved! I called Watts 247 who originally sold me the inverter. They informed me that ~160 Voc was required for the system to start drawing power from the array.

 

[BoxTruckLife]

I think your question was answered above:

I'm a noob so I was trying to wrap my head around the fact that it needs a minimum amount to start charging the batteries. If I am only able to get 150voc and OP is experiencing issues at around 140voc then I am concerned since in my application, I am unable to add more panels to the roof of the RV.

Sooo long story short I may have to pass up on this inverter and get something else.

 

[sunshine_eggo]

I'm a noob so I was trying to wrap my head around the fact that it needs a minimum amount to start charging the batteries. If I am only able to get 150voc and OP is experiencing issues at around 140voc then I am concerned since in my application, I am unable to add more panels to the roof of the RV.

Seller explicitly stated the reason it wasn't working. MPPT won't start charging below 160Voc.

Sooo long story short I may have to pass up on can't use this inverter and get something else.

Clarified.

 

[Herb]

Problem solved! I called Watts 247 who originally sold me the inverter. They informed me that ~160 Voc was required for the system to start drawing power from the array. I added another panel which gave me 165Voc at this point in the day. The system started drawing power from the array. Under load the array dropped as low at 130Vmp, which is just above the 120Vmp spec. That explains why the 140Voc (4 panels) didn't work--it undoubtedly would drop below 120Vmp under load.
Now I can start to figure out what kind of loads this system can handle once I add all my panels to the equation. It's very cool to see the system working, and adjusting current to battery vs. current to load for various loads, (my load for testing is a heat gun with adjustable heat setting).

Makes sense! Glad is working for you! There are a lot of details to be learned from these things!