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2 EG4 3000's blown up.

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Johno1066

Solar Enthusiast
Joined
Feb 2, 2023
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145
Location
Lottsburg VA USA
Tried fitting power meters into my incoming pv negative's by means of shunt resistors. The main problem is that most of the DC power meters operating voltage does not exceed 100 volts. and my pv voltage is around 190 volts. I found one that could read up to 200 volts and you could use a separate power supply to operate the device. Bought one and hooked it up to one of the EG4's using a 12 volt DC small charger similar to these little telephone chargers. The little device worked quite well could now see the pv voltage, pv current, watt input and recorded watt hours over time. What i wanted was a means to record my watthour input over a normal day, but as I had 2 EG4's in parallel I ordered another of those devices. Now with only one power supply I set up 2 sets of pushin connectors so as to be able to power both devices from a single source. Wired up the second device and before cutting the other pv negative connected up the second device to make sure it worked. As it was working I disconnected its power shut down the pv input and connected the negative through the shunt and turned the pv back on and all was well until I pushed in the 12 volt power into the second device, there was an immediate pop and all shut down right into the batteries as well. The only thing i can think of is that the 12 volt power supply made common the 2 negatives of the 2 pv streams and resulting in 2 dead EG4's I have ordered 2 replacements and have spoken to Signiture Solar about possibly repairing the damaged ones but that does not look too good. Anyone else do repairs on these things as I suspect that the charge controllers are probably damaged.
 
Yeah It looks like I will have to go to solar assistant, but the one EG4 had problems with its Wi-Fi output so that was a problem that has been solved the hard way. The other is that I monitor the system often visually, with solar assistant that means opening up and monitoring the computer dont know if it will work on a cell phone.
 
Bummer. I have run PV shunt setups with the only issue being some of the models will lose display readout (The LCDs go wonky). But I never attempted to run 2 off 1 power supply. In fact I gave up using the keep alive feature of having a external power and simply let the PV power the shunt. It does mean losing each days values once the sun goes down but I do not find that a problem.

ETA; I should mention the higher PV voltage AIO's may put a AC voltage onto the circuit going out to your panels. It is possible that between your two AIO's shunts you created an AC out of phase situation which caused the failure.
 
Last edited:
Johno1066 said:
Yeah It looks like I will have to go to solar assistant, but the one EG4 had problems with its Wi-Fi output so that was a problem that has been solved the hard way. The other is that I monitor the system often visually, with solar assistant that means opening up and monitoring the computer dont know if it will work on a cell phone.
Click to expand...
Works on cell phone.
 
When I sent in my EG4 3k for service through Solar Sovereign, I was told that they did not usually repair them, but would replace them with other units that had been returned to EG4 and tested as ok.
 
Mattb4, I think you are correct about the ac output on the pv cables, but I would not expect them to be out of phase with the units in parallel.
I would of been happy to let the pv voltage power the devices but could not find a monitor that would run on 200 volts dc.
 
Are your AIO's in Parallel or Stacked? (Parallel would be same voltage on 1 hot leg but Stacked gives you twice the voltage over 2 hot legs.)
 
Yeah, connecting the PV(-) inputs across two parallel inverters together without even checking for potential difference with a DVM sounds like a really bad idea, as well as an expensive learning experience.

I'm with everyone else, either Solar Assistant, or roll your own RS485 interface to the inverters, I mean they know the info you are looking for, and can report it back to you. I've got a pair of 18Kpv in parallel, and I get:
1722623527719.png
1722623559549.png

etc.
 
Yes but it is nice for me to walk past my laundry and read the pv outputs in watts for the day and also the kwh of the ac output for the last 24 hours. That was all I was looking for. The tie to the two pv negatives was inside the devices and both inverters were parallel 120 volts and yet Bang. Looking at Ebay I could have got at least 5 kw of Mrpower inverters for less than the cost of the EG4 3000 but have no idea if they are any good.
 
Johno1066 said:
Yes but it is nice for me to walk past my laundry and read the pv outputs in watts for the day and also the kwh of the ac output for the last 24 hours. That was all I was looking for. The tie to the two pv negatives was inside the devices and both inverters were parallel 120 volts and yet Bang. Looking at Ebay I could have got at least 5 kw of Mrpower inverters for less than the cost of the EG4 3000 but have no idea if they are any good.
Click to expand...
 
I purchased 2 EG4 3000's from Signature Solar on the morning of the1st of August and got a tracking number by the afternoon but by the end of the 2nd of August UPS had not yet picked up the inverters. In Texas does UPS not collect daily as they do in most states or is it just the statement that orders cannot be cancelled once a tracking number is given. We will see how this goes and I will keep everyone posted. Maybe I will buy one of those 5Kw cheapies from Ebay just to keep things going.
 
The EG4 3K units are pretty robust units. Definitely add Solar Assistant to your setup. Try one inverter first before you add the 2nd one. There's my $0.02
 
I was under the impression that Solar assistant would work off the wi fi dongles from each inverter. Is that not the case. I tried those power meters on one inverter first and it worked great, I did not take into account that the power supply internally connected the 2 pv negatives together.
 
Johno1066 said:
I was under the impression that Solar assistant would work off the wi fi dongles from each inverter. Is that not the case. I tried those power meters on one inverter first and it worked great, I did not take into account that the power supply internally connected the 2 pv negatives together.
Click to expand...
1722719052478.png
 
I will check that lot out once the new inverters arrive and are back online. I have pulled the board out of one of the EG4 3000's and will start trying to check out the system and isolate the fault. There is a short circuit between the Batt pos and neg, I pushed 50 amps into the fault to see if I could detect any hot components, but none were found. I guess those power mosfets work at a much higher amperage and still remain quite cool so that did not work. I would like to get some more information on this board but Signature Solar apparently does not have information they are willing to part with. Even a block diagram of the system would be of some help. Anyway I will just plug away and remove the banks of mosfets until the short circuit goes away and try to isolate the faulty section. got nothing to lose.
 
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