Help with PV setup

Pax

Pax

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I have a dedicated PV system consisting of 4x 435 panels, Growatt SPF3000Tl (24V) and a Hubble AM4 (2.75KWh) battery to isolate (from the grid) and feed my rater sensitive audio and video equipment . It is set up to feed in sequence Solar- Battery- Utility.

I started off with the system as is but using 2 x 100Ah deep cycle batteries in series (for 24V) before ‘upgrading’ to Li in late October. Batteries were then usually the source powering TV and audio from dark to maximum 22h00, when all would be on standby only. By morning, the Deep Cycle batteries were still OK, but with the Li, by 06h00 to 07h00, the system reverts to utility power as the battery has gone dead and the sun (on the west coast) is not sufficient yet. It is getting worse over time too, with the system reverting to utility earlier and earlier despite having longer sunshine in the evenings. My panels face NNW.

Now, as the Deep cycle batteries were set up to be drained to a max of 50%, while the Li one is drained to 80%; my understanding is that the Li battery should outlast the Deep cycle ones by a rather large margin, yet is not so. The installer maintains that the inverter settings must be changed, and his contention is that the sequence should be Utility – solar- battery, but that defeats the purpose of the setup to isolate my equipment.

My contention is the Li battery is defective/does not have the purported capacity. Please advise?
 
Not too sure about the Growatt inverters but I have seen a few installs on the Sunsynk inverters where the battery usage was set to 80%. This meant that only 20% could be used. The setting had to be on 20% to use 80% of the battery.
 
Pax said:
I have a dedicated PV system consisting of 4x 435 panels, Growatt SPF3000Tl (24V) and a Hubble AM4 (2.75KWh) battery to isolate (from the grid) and feed my rater sensitive audio and video equipment . It is set up to feed in sequence Solar- Battery- Utility.

I started off with the system as is but using 2 x 100Ah deep cycle batteries in series (for 24V) before ‘upgrading’ to Li in late October. Batteries were then usually the source powering TV and audio from dark to maximum 22h00, when all would be on standby only. By morning, the Deep Cycle batteries were still OK, but with the Li, by 06h00 to 07h00, the system reverts to utility power as the battery has gone dead and the sun (on the west coast) is not sufficient yet. It is getting worse over time too, with the system reverting to utility earlier and earlier despite having longer sunshine in the evenings. My panels face NNW.

Now, as the Deep cycle batteries were set up to be drained to a max of 50%, while the Li one is drained to 80%; my understanding is that the Li battery should outlast the Deep cycle ones by a rather large margin, yet is not so. The installer maintains that the inverter settings must be changed, and his contention is that the sequence should be Utility – solar- battery, but that defeats the purpose of the setup to isolate my equipment.

My contention is the Li battery is defective/does not have the purported capacity. Please advise?
Click to expand...
What were your BULK/ABSORBTION/FLOAT/LOW CUTOFF voltages set to on deep cycles VS AM-4?

Is there a comms cable for the AM-4?
 
@wingnut771 I can look up, but they are quite different. I recall for the deep cycle around 21.? V and 25.?. The Li batteries are exactly as per their manual, from memory, 23.1V; 28V and 29.1V. The battery has 6 leds showing charge. All go off by the morning and all are on in the afternoon.

There is no coms cable - seemingly not necessary according to the manual and the installer.
 
Pax said:
@wingnut771 I can look up, but they are quite different. I recall for the deep cycle around 21.? V and 25.?. The Li batteries are exactly as per their manual, from memory, 23.1V; 28V and 29.1V. The battery has 6 leds showing charge. All go off by the morning and all are on in the afternoon.

There is no coms cable - seemingly not necessary according to the manual and the installer.
Click to expand...

I am not an expert but i think it should be:

bulk/equalise: 29
float: 28
cut off: 22.5

and i think around 40A per battery
 
Mypro-D said:
Not too sure about the Growatt inverters but I have seen a few installs on the Sunsynk inverters where the battery usage was set to 80%. This meant that only 20% could be used. The setting had to be on 20% to use 80% of the battery.
Click to expand...
This is a very good point being raised here, maybe OP must post the settings, because something might not be set properly.
 
Try doing a equalise charge @ 29V from grid? Maybe PV is not enough to equalise long enough to top balance cells?

Get a comms cable.
 
OK, I checked, exactly as per the manual, voltages are set Low 23V; Float, 28V and Bulk 29V. All by the book.
 
@wingnut771 How long should the Equalise charge be maintained - the battery is usually fully charged by 13h00 latest and then gets sunlight till at least 18h30. I'm not very knowledgeable in the field, I can sue it though, LoL!

My manual clearly on page 5 says the AM4 low is to be set at 23V. I can change, but it may be at risk of the warranty.
 
Pax said:
@wingnut771 How long should the Equalise charge be maintained - the battery is usually fully charged by 13h00 latest and then gets sunlight till at least 18h30. I'm not very knowledgeable in the field, I can sue it though, LoL!

My manual clearly on page 5 says the AM4 low is to be set at 23V. I can change, but it may be at risk of the warranty.
Click to expand...
The inverter and the BMS manages all factors related to correctly charging the battery, all.you have to.do.is sekect th d righ t settings and relax.
 
Pax said:
@wingnut771 How long should the Equalise charge be maintained - the battery is usually fully charged by 13h00 latest and then gets sunlight till at least 18h30. I'm not very knowledgeable in the field, I can sue it though, LoL!

My manual clearly on page 5 says the AM4 low is to be set at 23V. I can change, but it may be at risk of the warranty.
Click to expand...
Hmmm, max 2 hours I would say so there is enough time it seems.

How are the battery cables?

Consider investing in a coms cable so inverter can control battery charge.

But I agree, you should be getting double the performance of the deep cycles.

EDIT: Okay, leave it at 23V.
 
It's not unheard of for lithium batteries to go faulty. Call the supplier and ask for assistance. One of my BYDs stopped working properly after a couple of months - capacity dropped to a fraction of what it should have been, cells wouldn't balance properly.
 
All cables per spec and brand new. A very reputable installer from CT did the job. The battery did come with a coms cable, but I'll need someone who knows how to set it up as it seems not just for plug and go. What I do see is that the inverter can only be set to Li battery where percentages can be managed "when communicated with BMS" (per manual). It may default to 50%? Don't know enough!
 
Pax said:
All cables per spec and brand new. A very reputable installer from CT did the job. The battery did come with a coms cable, but I'll need someone who knows how to set it up as it seems not just for plug and go. What I do see is that the inverter can only be set to Li battery where percentages can be managed "when communicated with BMS" (per manual). It may default to 50%? Don't know enough!
Click to expand...
Get this very reputable installer to complete the job then! There needs to be communication between the inverter and BMS.
 
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