Any experts capable of cracking this faulty system?

Hello.

I am creating a simple off-grid installation to power a few small things off to the side. However, so far the system is not working at all and I cannot figure out the problem. I've tried getting answers here a few times, but questions have been asked when I couldn't answer them (either system was down, or winter prevented access). To address this, I created a web page which provides videos of my install, item specifications, e.g., panel specs, voltmeter readings, and anything else I can think of that will help me get answers. In trying to honor this forums rules, I replied to my original posts with answers once I had them, but apparently older posts do not get attention as nobody responded.

My system consists of:

1. 7 used panels (4 in series, 3 in series, y-branced into 1),
2. 1 brand new Eg4 3kw Inverter, and 4 eco-friendly batteries from amazon. I believe the Eg4 inverter is faulty - but I cannot be sure.
3. 4 brand new Eco-Friendly 12v 100amp LiFeP04 batteries. $1k less than than Eg4 batteries - so perhaps the problem lies here.

I've never had a load on this system outside of the Eg4 unit itself, which has a self consumption rate of about 15-50w. The problems I face are merely in keeping the system running with no draw.

The issues.

After a full recharge on the batteries, the system starts up and registers everything as working, i.e., the Eg4 display shows the panels feeding the batteries.
Within 4-6 days the Eg4 reveals 6p errors. After a full battery recharge, the system starts again.

I grew tired of this cycle. The winter curtailed troubleshooting, so I shut the system off and left it alone until now. This time around, I'm getting different results. After a recharge, the system starts up as usual. Within days, the system sometimes shows an error type 4 (which seams to suggest heating issues), and sometimes just shuts off. Oddly, the shunt attached shows the batteries at 100%.

I feel like i have one of 2 things going on. Either I was shipped a faulty Eg4 inverter, or these eco-worthy amazon batteries are faulty. On one hand, I think its the batteries because I had one faulty on the shipment, and another that seems to lag behind the others in charge. On the other, I think its the inverter because the batteries do show a full charge and are capable of being charged via AC chargers.

I do not know how to figure it out. What might you experts recommend?

Thanks
Jeff

You can't parallel mismatched strings so that's one problem.

For the batteries, first troubleshooting step with 12v in series is to put them all in parallel and charge them as a 12v bank to balance them. The downside of using 12v's is they can't stay balanced in series.

Voltage is not high enough. That inverter needs minimum 120V.

Since specs are close enough on the solar panels, put all 7 panels in series.

With 3 panels, the voltage is 112v (37.2 x 3). According to the spec sheet, you need a minimum 120v.
Put all 7 panels in series for around 250v (well under 500v max). You may loose a little in amps.

hwy17 said:

You can't parallel mismatched strings so that's one problem.

For the batteries, first troubleshooting step with 12v in series is to put them all in parallel and charge them as a 12v bank to balance them. The downside of using 12v's is they can't stay balanced in series.

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others are telling me to put all PV's in one series, but you're telling me I can't parallel mismatched strings. Can you clarify?

jeffnoyes1 said:

others are telling me to put all PV's in one series, but you're telling me I can't parallel mismatched strings. Can you clarify?

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Yes. You cannot have 4 panels paralleled to 3 panels. You can do 3 paralleled to 3, or you can do 7 in series.

Others have now actually looked at the details of your MPPT and concluded 7 is better for you than 3+3. I didn't look into those details and I assume they are right.

hwy17 said:

The downside of using 12v's is they can't stay balanced in series

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Fortunately the OP has a 12 to 48 V battery balancer, so that should be working. It sounds like his problem is that the PV input voltage isn’t high enough to meet the minimum and actually charge the batteries from solar.

Any thoughts on the 4p error? Do you think this is because I had the panels connected incorrectly?

https://diysolarforum.com/posts/544288 says that’s (Battery) Voltage Too High, which could be your batteries getting out of balance and one of them shutting down on charge. Do you have a DVM, and can you take voltages of all four batteries just before and after they trip out?

jeffnoyes1 said:

Any thoughts on the 4p error? Do you think this is because I had the panels connected incorrectly?

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Get the proper PV voltage to the AIO then work from there.

jeffnoyes1 said:

Any thoughts on the 4p error? Do you think this is because I had the panels connected incorrectly?

Click to expand...

Fault 4 is "Over temperature of PV module"... unless you have an actual temp sensor hooked to the inverter ( is inverter even capable of this?), how would the inverter know it's over temp? I'm guessing by extrapolating the low voltage input of the panels....

Literally took me 1 minute to find the fault table in the manual (page 60 of 64)...
READING THE MANUAL USUALLY HELPS !

fnnwizard said:

Fault 4 is "Over temperature of PV module"... unless you have an actual temp sensor hooked to the inverter ( is inverter even capable of this?), how would the inverter know it's over temp? I'm guessing by extrapolating the low voltage input of the panels....

Literally took me 1 minute to find the fault table in the manual (page 60 of 64)...
READING THE MANUAL USUALLY HELPS !

https://eg4electronics.com/backend/wp-content/uploads/2022/07/EG4-3000EHV-48-V2-Manual.pdf

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My mistake, he was also getting 06 error, and that threw off my Google Fu.
04 WARNING is low battery, which makes more sense, I also don't know how the inverter knows PV module is overtemp...

wpns said:

https://diysolarforum.com/posts/544288 says that’s (Battery) Voltage Too High, which could be your batteries getting out of balance and one of them shutting down on charge. Do you have a DVM, and can you take voltages of all four batteries just before and after they trip out?

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I never really know when its going to go out. Everything seems fine, then its not. But Im also not out there every hour checking it. Its kinda like diagnosing cancer. Everything seems good, but underneath theres something stinky brewing but its so slow and silent you just cant know.

fnnwizard said:

Fault 4 is "Over temperature of PV module"... unless you have an actual temp sensor hooked to the inverter ( is inverter even capable of this?), how would the inverter know it's over temp? I'm guessing by extrapolating the low voltage input of the panels....

Literally took me 1 minute to find the fault table in the manual (page 60 of 64)...
READING THE MANUAL USUALLY HELPS !

https://eg4electronics.com/backend/wp-content/uploads/2022/07/EG4-3000EHV-48-V2-Manual.pdf

Click to expand...

Yes, I read the manual too and 4P does suggest over temperature. How ever, either the manual or someplace else (I cant recall) suggested that Error 4 can be a catch all. Temperature didn't make any sense to me either.

wpns said:

My mistake, he was also getting 06 error, and that threw off my Google Fu.
04 WARNING is low battery, which makes more sense, I also don't know how the inverter knows PV module is overtemp...

Click to expand...

I had not seen that Error 4 could be reference low battery. That's interesting.

jeffnoyes1 said:

I had not seen that Error 4 could be reference low battery. That's interesting.

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Note: not ERROR 4 but WARNING 4 is low battery

I would take the battery apart and measure the voltage of each. See how far the are apart and report back.

If they are more than 0.03 volts apart from each other when totally disconnected but are fairly close then parallel them and charge with a 12v charger for a day or two. Then disconnect and let them rest an hour and check again.

jeffnoyes1 said:

I had not seen that Error 4 could be reference low battery. That's interesting.

Click to expand...

That’s WARNING 4 = low battery. Not ERROR 4 = over module over temp.

jeffnoyes1 said:

I never really know when its going to go out. Everything seems fine, then its not. But Im also not out there every hour checking it. Its kinda like diagnosing cancer. Everything seems good, but underneath theres something stinky brewing but its so slow and silent you just cant know.

Click to expand...

Have you put all 7 modules in series yet? It's the voltage. Your 4s modules are likely teetering under/over 120V, putting out over 120v when it's cooler than 25C° and less when it heats up/doesn't get hit directly by the sun's rays. This is what's brewing. Wire all the modules in series, simple as that.