EG4 in 1P2/2P2 keeps dropping solar charge connection

[TurbineTester]

Every so often i will come into my garage and have found that one or both of my EG4 inverters has stopped taking solar energy and charging the batteries. Once it was both of them, and today it was only the 2P2 inverter. Resetting the inverter (totally turning off by disconecting PV and inverter switch pressed off) will resume chargign the batteries. Today 2P2 went from 0A into batteries, to 9A into the batteries after the reset. I can understand the solar chargign may stop when it is dark or overcast, but shouldn't it automatically resume when there is enough light to charge, every time? What could be happening to force me to completely reboot the inverter to get charging to resume?

 

[TomC4306]

PV voltage not high enough.
Need more details.

 

[TurbineTester]

This has happened when the sun is shining bright outsides and PV voltage above 350v.

 

[PreppenWolf]

Are your PV leads still securely fastened at the inverter? Possible arcing at the connection?

 

[Quattrohead]

Captain obvious here, are your batteries fully charged when this happens ?

 

[PreppenWolf]

Captain obvious here, are your batteries fully charged when this happens ?

Woah, woah, woah. Let's save the logical, simplest answer for page 9 ?

 

[TurbineTester]

Are your PV leads still securely fastened at the inverter? Possible arcing at the connection?

PV Leads secure and connected. All it takes to remedy the problem is to completely power off the inverter and turn back on.

 

[TurbineTester]

Captain obvious here, are your batteries fully charged when this happens ?

No they are not, but good idea ? The first time they were nearly completely depleted and the sun was shining bright over head, but no charging. They were inverting and powering small loads in my garage, but not charging. Reset the inverters and they immediately started putting current to the batteries as well as running small loads.

 

[EPicTony]

No they are not, but good idea ? The first time they were nearly completely depleted and the sun was shining bright over head, but no charging. They were inverting and powering small loads in my garage, but not charging. Reset the inverters and they immediately started putting current to the batteries as well as running small loads.

I think you have too much panel "36x455 Watt Solarever Panels, 4x9 panel strings" I just went thru this on another thread, 8 is the max if you live in a cold climate. You will exceed Max Voc with 9 in a string. Just a warning so you don't damage your inverters.

 

[TurbineTester]

the 9 panels is undersized to the max VOC of 500v per the manufacturer:

 

[PreppenWolf]

the 9 panels is undersized to the max VOC of 500v per the manufacturer:View attachment 133944

Those values are not for cold weather. In cold temps solar panel voltage rises above the listed values which are taken at a standard warm temp.

 

[EPicTony]

 

[EPicTony]

Where are you located ? From that you can get the multiplier for the Max Voc. In Ohio where I live it is 1.13 at -10deg F. This means my Solever 455w panels in cold winter can put out 49v x 1.13 = 55.3v 55.3 x 8 = 442v 55.3x9 = 498v.
I'm not being critical just pointing out what I just learned myself last week.

 

[TurbineTester]

I'm in Georgia, and according to SA i've never been higher than 419

 

[Zwy]

Where are you located ? From that you can get the multiplier for the Max Voc. In Ohio where I live it is 1.13 at -10deg F. This means my Solever 455w panels in cold winter can put out 49v x 1.13 = 55.3v 55.3 x 8 = 442v 55.3x9 = 498v.
I'm not being critical just pointing out what I just learned myself last week.

Ran it thru Midnite calculator, results in pdf. At 30F the VOC is too high. Even at warmer temps it's pushing it at 444.15V

 

[TurbineTester]

I guess i see what you are saying based on your calculations, but the real world data doesn't support that estimate. I'm not getting any over voltage warnings or errors and the data shows nothing that high that i can see.

 

[Zwy]

I guess i see what you are saying based on your calculations, but the real world data doesn't support that estimate. I'm not getting any over voltage warnings or errors and the data shows nothing that high that i can see.

So you are saying the calculator is wrong and you are right?

VOC is open circuit voltage, if the SCC sees VOC above it's operating rating, it will shut down. This is different than the voltage under load which is what you see on the display. The MPPT will switch to achieve maximum power point during charging, at some point it will switch, the VOC will exceed the rating and the SCC will shut down.

One problem with exceeding VOC is damage to the SCC and the possibility it will allow full PV voltage to pass thru to the batteries.

The EG4 is rated to operate up to 450VOC and is rated for a max of 500VOC. Exceeding the 500VOC will cause the damage. Above 450VOC and below 500VOC, the SCC will shut down. The engineers were smart about this, exceed the 450VOC and the unit won't charge, thus a safety factor.

 

[Quattrohead]

I guess i see what you are saying based on your calculations, but the real world data doesn't support that estimate. I'm not getting any over voltage warnings or errors and the data shows nothing that high that i can see.

Check your graph as the sun comes up etc, you will see the voltage rise until the MPPT starts to draw current and then it will fall. This can oscillate quite a bit until there is enough power. I had this randomly with no obvious error on my Solark with Panasonic panels, I had to remove a panel.

 

[TurbineTester]

After observing this for several weeks now, i am no longer seeing it drop the solar charge connection entirely. It seems to be functioning as designed.

 

[SignatureSolarJames]

Hooray!