What am I missing? EG4 3000W off grid not acknowledging PV input

[Xtinabritannica]

I'm clearly missing something. My EG4 battery and inverter are running fine, but the inverter will not acknowledge the PV voltage.

I started with one panel only, mostly because I'm a tiny thing and I need help to lift them ?. But even one panel out of the three has more voltage than the battery, so I don't believe that's the issue.

I checked:

1. The PV connections on both ends
2. Made sure the MC4 connectors on the panel weren't installed backwards at the factory
3. The voltage on both ends reads 62.8 V, so there's no drop
4. The settings on the inverter for priority, and amps

Thoughts?

SPECS/Info:

• 32ft Keystone 2003 Travel Trailer (will be stationary for a while)
• Parallax 7300 120VAC -> 12V Converter already installed with circuit board
• EG4-LifePower4 Lithium Battery | 48V 100AH
• EG4 3kW Off-Grid Inverter | 3000EHV-48 | 3000W Output | 5000W PV Input | 500 VOC Input
• 3x 345W SunPower in Series
• Rated Voltage (Vmpp) 57.3 V
• Rated Current (Impp) 6.02 A
• Open-Circuit Voltage (Voc) 68.2 V
• 12v 27DC Marine Battery

 

[Samsonite801]

Well on the specs sheet it clearly does say PV voltage: 120VDC - 450VDC

Ref:

https://signaturesolar.com/content/documents/EG4/EG4%203000EHV-48%20Inverter%20Specification%20Sheet%20Rev%20C.pdf

 

[Xtinabritannica]

Well on the specs sheet it clearly does say PV voltage: 120VDC - 450VDC

Ref:

https://signaturesolar.com/content/documents/EG4/EG4%203000EHV-48%20Inverter%20Specification%20Sheet%20Rev%20C.pdf

Thank you. I knew I needed a new pair of eyes. It's over 90 degrees and I feel like I'm thinking through a brick wall ? ?‍

 

[Samsonite801]

Good luck getting it all going bro

 

[sergea]

You need to be as close as possible to Vdc max input and respect Total Voc < Vdc condition. I would say 7 of your panel in serie is ideal. Do you live in a cold country ?

 

[Xtinabritannica]

It ended up being under voltage, as @Samsonite801 had guessed. Once we had more than 120v of PV input, it was a happy camper. We now have 4 panels, and are running the mini split all day with zero issues.

 

[dab1294]

Just curious because I’m trying to plan a system like this, How do you have the EG4 wired into the RV?

 

[Rubicon_Traveler]

Another question for another newbie, so when the sun starts to go down or a cloud goes over, does the voltage drop and therefor the inverter stops until the voltage hits 120?

 

[MrThisIsME]

Another question for another newbie, so when the sun starts to go down or a cloud goes over, does the voltage drop and therefor the inverter stops until the voltage hits 120?

In simple terms, the current (amps) drops not the voltage.

 

[Rubicon_Traveler]

Thanks

 

[Samsonite801]

In simple terms, the current (amps) drops not the voltage.

Yeah to kind of augment what MrThisIsME said, cloud comes over, volts and current drop somewhat, MPPT controller 'relaxes' load (resistance on the circuit to let voltage stay higher than startup voltage, does a full MPPT sweep (pulls voltage down to low-point threshold, and then relaxes circuit to voltage high-point, recalculates watts all along that curve) and finds maximum power point again in watts (adjusts resistance/load on circuit, which varies the volts/amps to find maximum watts it can get based on what it has to work with). Perhaps in the end this looks a bit like voltage didn't drop, and current is a lot lower (the new place where it finds maximum power point in watts).

That's just a simplified description, there are many articles on lots of different MPPT sweeping algorithms known in the industry. But the main point to understand, is that, the MPPT is like a complex version of a variable buck converter, which can alter the resistance on the PV circuit, by placing low load or high load on it to either relax the circuit all the way up to Voc voltage, or it can theoretically pull the volts all the way down to low startup limit, or maybe even Isc (during an MPPT sweep), to pull the amperage up to maximums. Since the solar panels are not linear in their relationship between voltage curve and amperage curves, the point in which maximum power point in watts is located at any given time, has to be 'found' by the MPPT algorithm. It's a very dynamic circuit.

 

[Xtinabritannica]

Just curious because I’m trying to plan a system like this, How do you have the EG4 wired into the RV?

Take a look at my graphic on the post linked at the bottom. While a couple people had some suggestions for efficiency, our 48v > 12v converter wouldn't work for some reason. We're still researching why. In the interim, we have the 120v > 12v converter still in place (that came with the RV).

The EG4 runs to the shoreline AC input on the circuit board, and we are no longer using the shoreline cable at all, since we did not end up getting a transfer switch. This was an issue of the fact that the EG4 manual has two different ways to wire up the green (ground) wires to the EG4, depending on whether or not you have shore power. But that's a whole other barrel of monkeys, so we opted to go 100% solar for now, since we have enough panels to keep our 5000kw EG4 battery happy/charged, and still run our mini split.

We found out we do NOT, however, have enough battery power to run the Dometic fridge overnight. It pulls around 500-550 watts consistently, (including the 75ish watts for the inverter on the EG4 to run). And we found that the battery discharged too fast overnight. We didn't make it from sunset to after sunrise when the panels were taking in enough Amps to recharge the battery. So for now we have an external chest freezer on its own solar setup.

Wire Map for Keystone 2003

 

[LuisNJ]

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