Watt very Fast drop very fast jump on solar power

[Montanat]

Hi guys I just installed 6 panels 545w jinko tiger pro and started loading.
I have 5k inveter & 300ah lifepo4 battery.

I was drawing 1700w with AC on at 12 noon where the sun was peak time. The power from panels reached 2300w then dropped to 600w then back to 2400w and kept doing this cycle very fast (attached is a video).
Someone please explain to me what's wrong and how to fix this issue.

 

[MichaelK]

Are your six panels in one long series string, or do you have multiple parallel strings? One thing I could guess is that there's a poor connection somewhere in one string, and you are getting extra current from a string getting intermittantly cut off. Maybe the solar wiring fluttering in the breeze, that causes flexing that breaks the connection.

 

[OffGridInTheCity]

Momentary clouds could cause an MPPT algorithm to fluctuate significantly. Any clouds passing by?

As @MichaelK asks - if you have 1 long string any shadow (just a few square inches) on any of the panels in the string could cause a significant dip.

 

[Montanat]

Are your six panels in one long series string, or do you have multiple parallel strings? One thing I could guess is that there's a poor connection somewhere in one string, and you are getting extra current from a string getting intermittantly cut off. Maybe the solar wiring fluttering in the breeze, that causes flexing that breaks the connection.

It's 1 long series only . Panels are 3 meters above ground no wind at all.

 

[Montanat]

Momentary clouds could cause an MPPT algorithm to fluctuate significantly. Any clouds passing by?

As @MichaelK asks - if you have 1 long string any shadow (just a few square inches) on any of the panels in the string could cause a significant dip.

There was some clouds today yes the current dropped untill the cloud passed. But this fast up and down dip stayed around 15 minutes then returned stable to 1700w. No wind at all today.
I have 70 meters 4mm PV wires between the panels and the inverter but I don't think its the cause of this fast fluctuation

 

[Bud Martin]

Is this the first time you see the issue? Did it do this before?
Does it do the same if you do not run the AC or heavy loads but other light loads instead?
Do you have and fuse or circuit breaker between the panels and the charge controller?
It can be due to poor connections that heats up when high current starts flowing.
Can you monitor the PV input Voltage when this is happening?
Can you show us the pictures of the whole setup so we can see how all the components are wired together?

 

[Montanat]

Is this the first time you see the issue? Did it do this before?
Does it do the same if you do not run the AC or heavy loads but other light loads instead?
Do you have and fuse or circuit breaker between the panels and the charge controller?
It can be due to poor connections that heats up when high current starts flowing.
Can you monitor the PV input Voltage when this is happening?
Can you show us the pictures of the whole setup so we can see how all the components are wired together?

This is my 1st day of panel use.
I saw this today on 1700w load for around 15 minutes then it went stable (with AC on).
I have a 10amp breaker between panels and the inveter yes.
I can monitor the voltage with a multimeter (will do it today)

I have 63amps breaker between battery and inverter.
10amps breaker between panels and inverter.
120amps beaker built in the lithium battery.
25mm cables for all.
4mm cables for the panels/inverter.
5k hybrid inverter (500 vcd)
6 x 545w jinko panels.

Attached are pics of the setup (it's a bit messy I didn't finish putting everything in place yet)

 

[acdoctor]

Something I see in the video is when the watts in drops the charge light goes out. Maybe you are hitting float volts. Whether batteries are fully charged or not if it hits float wattage will drop off.

 

[Montanat]

Today the system didn't fluctuate too much. It did when input reached 2470w, it drops immediately to 2390w. This happened about 6-7 times in 1 minute duration.

Another question. I have 6x545w panels shouldn't I get more than 2400w during sun peak time? Anything I can do to improve the input? (panels are facing south)

 

[acdoctor]

I don’t know what the temperature is when you are getting 2500 watts but if it’s 90 deg F or above 75% of the name plate is about right.

 

[Montanat]

I don’t know what the temperature is when you are getting 2500 watts but if it’s 90 deg F or above 75% of the name plate is about right.

It was 90f (32C). And we have high humidity here (66-70%)

 

[acdoctor]

Glad to see you upgrade those batteries.?

 

[Montanat]

Glad to see you upgrade those batteries.?

It was a nightmare but I still have them. The Suoer inverter is reaching 60.5v bulk/float on solar which is a bit better than the 57.6v I use to get on grid and gravity is 1.260 now.
I'm switching between the lead acid for low load and the lithium for heavy load.
We only have 1 hour power a day since 3 month from the electricity company now and soon they will cut it off completely no more fuel at all.

 

[acdoctor]

Wow I hate to hear it’s gotten worse for you as far as the intermittent grid goes.
You are at about 35 deg Latitude which is about the same as me. I am a long way from a coast though. I do have high humidity though. Last week it was 105F and 38%. Lots of summer days it’s mid 90’s and 50 to 65%.

The 70 meters of PV wire is that one way or round trip?
If that’s round trip you are loosing about 100 watts in the wire due to voltage drop. I would want to measure the voltage of the PV input at the inverter and compare it to the data on the panels.

There are tools online like PVWATTS that can help calculate your PV potential.
Mine is about 4.8 hours yearly average with ideal panel tilt angle. But mid December it’s only about 2.5 hours. For you that would be 2.5 x 3270 watts is 8175 watts per day. Your inverter has a consumption of something like 60 watts x 24 hours is 1440 watts from the 8175 is 6735 watts of usable 240 vac. Or 280 watts an hour.

 

[Montanat]

Wow I hate to hear it’s gotten worse for you as far as the intermittent grid goes.
You are at about 35 deg Latitude which is about the same as me. I am a long way from a coast though. I do have high humidity though. Last week it was 105F and 38%. Lots of summer days it’s mid 90’s and 50 to 65%.

The 70 meters of PV wire is that one way or round trip?
If that’s round trip you are loosing about 100 watts in the wire due to voltage drop. I would want to measure the voltage of the PV input at the inverter and compare it to the data on the panels.

There are tools online like PVWATTS that can help calculate your PV potential.
Mine is about 4.8 hours yearly average with ideal panel tilt angle. But mid December it’s only about 2.5 hours. For you that would be 2.5 x 3270 watts is 8175 watts per day. Your inverter has a consumption of something like 60 watts x 24 hours is 1440 watts from the 8175 is 6735 watts of usable 240 vac. Or 280 watts an hour.

It's a 2x4mm (+/-) wire from the panels direct to the inveter.

Maximum I could see from the 6x545w panels is 2470w. Not stable when breeze and clouds pass it drops, I'm consuming around 2.2kw for 2 hours a day to cook using the electric oven and plate. And Around 3 hours AC (1600w). The rest is 42"tv, 24ft fridge, some led lamps...
The battery is backing up when current drops then recharge when back again.

Voltage at the PV wires I saw it once when I installed the panels (1st day of installation) at 8am it was 275v I will check again in peak sun time.

1 hour from the grid only yes and 2 days now not even 1 minute.

Attached is the panel data I will never know how to calculate what you told me to do ?.

 

[acdoctor]

What angle from horizontal are the panels?
Will you be able to adjust the angle of the panels this winter?
What compass heading are the panels facing?
Are all 6 on the same angle and heading?
Is the 70 meters the distance between panels and inverter?
Or is 70 meters twice the distance from panels to inverter?
How early are the panels getting sun? How late does the sun leave them?
Is there anything casting a shadow on them at any part of the day now?
Does it look like there will be in the winter when the sun is lower?

 

[Montanat]

Those are the panels seen from my balcony. (photo attached).
I just measured angle and compass right now (photos).
They are 4 meters above ground. I had no other choice (not allowed to be on my building roof).
They are fixed not adjustable.
All 6 same angle / heading.
70 meters are distance from panels and inverter yes.
Sun rise at 5.45, leave around 6pm.
No casting or shadow, just the 2x4mm wire coming to the inverter is above them right side.
They are not setup for winter and no idea if my building will block the sun in winter time I have to check.

 

[acdoctor]

The 4 mm wire is eating up 145 watts of your production. 6 mm would be 60 watts of loss.
I can’t tell anything from the panel picture but you mentioned a wire casting shadow if at all possible I would move it.
The picture is from pvwatts it shows what production you can expect monthly.

So your new battery is about 12.5 kw of usable capacity 14 kw in a pinch.
In the summer months you can expect about 20 kw of production a day. The bulk of that is generated in about 6 hours.
How are you able to tell how full or empty the new battery is?

 

[Montanat]

The 4 mm wire is eating up 145 watts of your production. 6 mm would be 60 watts of loss.
I can’t tell anything from the panel picture but you mentioned a wire casting shadow if at all possible I would move it.
The picture is from pvwatts it shows what production you can expect monthly.

So your new battery is about 12.5 kw of usable capacity 14 kw in a pinch.
In the summer months you can expect about 20 kw of production a day. The bulk of that is generated in about 6 hours.
How are you able to tell how full or empty the new battery is?

The battery BMS is built in and it doesn't communicate with the inverter i have, but it has 4 led lights each light is 25% capacity left.
I've been consuming electricity for 3 days on solar and battery now, no grid at all not even 1 minute. Battery goes down to 52.3v maximum and 2 led lights are blinking up (charging in the morning when sun goes up).
Today is very cloudy its 10am and I took some pics (attached).
Current : minimum 800w maximum 1850w so far.
Charging : min 10a max 27a
Voltage from pv : 215-230v
Battery voltage : 53.8v so far

The battery bulk and float voltage as per manual is 57.6v. When It reaches 55.6v it jumps to 57.6v immediately.

 

[Montanat]

Update: 3000w at 1pm