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EG4 6500EX voltage is WAY off

JWLV

-.-. --.-
Joined
May 27, 2020
Messages
851
Just hooked up a full rack of 6 Ruixu server batteries to my EG4 6500EX. The voltage displayed on the EG4 is way off. Is there a way to adjust it?
The battery is nearly full (97%). The load is currently about 1.5KW. The smartshunt says the battery voltage is 52.90V and I confirmed it with my multimeter at the battery bus bars and at the DC terminals on the EG4. However, the display on the EG4 says the voltage is 51.0V. That's a difference of 1.9 volts. What gives?
Also, the SOC indicators on all 6 of the batteries themselves are 4 of 4. I know this isn't particularly accurate, but it gives a guesstimate that the batteries are at near full charge.

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There's no way to "calibrate" the voltage that the inverter sees. If you put a multi-meter on the battery terminals inside the inverter, what voltage do you read compared to the voltage read from the batteries?
 
My multimeter reads the terminals inside the inverter has the same voltage as what the shunt says it is, 52.9. The inverter still thinks it’s 51.0. The nearly 2 volt difference happens regardless if there’s a 2kw load or a 100w load. This is a new EG4 6500EX I just got from signature solar last week.
 
It could be a problem with your firmware Ver.
Have you checked If there is an update?
 
You could disconnect it from batteries and turn it back on to see if it changes. There is no way to change it. Or calibrate it yourself

Just checked manual again, not seeing anything useful.

I would try cycling it and seeing if it disconnects at proper voltage.
 
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I’ve disconnected it from the batteries several times while troubleshooting other issues. The voltage difference is actually the least of my worries right now. But it didn’t make any difference. The inverter still thinks the voltage is 2 volts lower.
 
I’ve disconnected it from the batteries several times while troubleshooting other issues. The voltage difference is actually the least of my worries right now. But it didn’t make any difference. The inverter still thinks the voltage is 2 volts lower.
What else is wrong?
 
There might be a way to calibrate it, I know Growatt has a method of calibrating some of their inverters. Definitely hit up signature solar and see if they have anything that can help you with this.
 
Are you sure your MM battery is good?
Had this a couple of years ago on one of mine where the battery was low and it reported wrong voltages when measuring.
 
There might be a way to calibrate it, I know Growatt has a method of calibrating some of their inverters. Definitely hit up signature solar and see if they have anything that can help you with this.
Yes please reach out to us! Tech support is here!
 
What else is wrong?

@Will Prowse One major concern I am having is that two appliances died right after I installed the EG4 6500EX. It might just be an amazing coincidence. This is another thread that talks about what happened: https://diysolarforum.com/threads/did-new-eg4-6500ex-kill-my-mini-split-and-chest-freezer.73971/

In summary, two days after I installed the EG4, my 10 year old chest freezer died. The compressor went bad. But I thought nothing of it because it's kind of old anyway. Then a few days after that, my MrCool mini-split gave an error code (PC 04) and now when I turn it on, the inside unit does not blow air, the outside fan does turn on, but the entire unit shuts off on its own after a few minutes without any error codes. So my main concern is that the EG4's AC output is not a clean sine wave. I have a mini oscilloscope coming from Amazon in a few days so I can see what the waveform looks like. And I know, you've been saying for years to use a LF inverter for such appliances.
 
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@JWLV this document I found with a quick duckduckgo search might help, I can't offer further guidance.


Thank you for the link. I find it really interesting that this document was so hard to find given that calibration is something that probably everyone wants to do or should do, even if the voltage is 0.5 volts off. Of course with mine being nearly 2 volts off, I definitely want to do this. Now I gotta buy that cable or the RS232 adapter cable.
 
There might be a way to calibrate it, I know Growatt has a method of calibrating some of their inverters. Definitely hit up signature solar and see if they have anything that can help you with this.

Yes, there should always be a way to calibrate it. I had a Growatt and it was in one of the hidden menus. The documentation to do this for the Growatt was pretty well hidden as well because it took me a long time searching Google to find out how to do it. The EG4 documentation to do the same is even more hidden. But thanks to @42OhmsPA, they found it for me.
 
Are you sure your MM battery is good?
Had this a couple of years ago on one of mine where the battery was low and it reported wrong voltages when measuring.

Yep, my multimeter's battery is good. It's good advice though, to always make sure your meter's battery is good. I've also had mis-readings due to a low battery.
 
SUCCESS!!! I followed the directions from the document that @42OhmsPA provided and now my EG4 6500EX is showing the correct voltage. (see pictures below). While I haven't heard back from Signature Solar, it is the weekend and I didn't expect to hear from them for at least a few days. So they get a pass on this one.

But what is really disappointing is that this inverter should never have passed QA from the factory in the first place. I mean, it is 2 volts off in reading the voltage. So when I program the bulk charge voltage at 56V, it might actually be charging at 58V because when the battery is at 58V, the inverter thinks it is at 56V. Another peeve is that I had to spend $10 on a USB to RS232 cable (EG4 only provided the Ethernet to RS232), and $80 on a 60V DC variable power supply to do the calibration. You have to instruct the EG4 to read the battery voltage (power supply) at 55.50 volts and again at 46.0 volts while issuing some commands through the comms cable in order to properly calibrate it. I had to do it fast too because the power supply I got was rated at 100W. At some point the EG4 begins to draw more than 100W during the startup sequence and cause the power supply to overload and shut off. Yes, I made sure that everything was shut off so that there was no load. That's a whole other thread about the EG4 idle current draw.


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I hate to bring an old thread back to life, but I have been experiencing this problem. I am more than frustrated that I found this thread and that this damn tool, that could have fixed the problem was even available. I've been on the phone with signature solar twice trying to fix this, updated the firmware before even calling them.

1) Why the hell didn't the tech support staff know about this problem/solution, and why hasn't it been fixed by now?

2) Why or how does an inverter make it out of QA being almost 2 volt off?

3) If there is a possibility of it needing future calibration (why was the tool created if not) why wasn't it put in to the freaking manual! Dunno, maybe include a link to the tool too?

Im planning to double my solar/battery solution next year (100kw). Doubt I will stay with signature solar at this point, and no longer plan to recommend there products to my customers either.
 
SUCCESS!!! I followed the directions from the document that @42OhmsPA provided and now my EG4 6500EX is showing the correct voltage. (see pictures below). While I haven't heard back from Signature Solar, it is the weekend and I didn't expect to hear from them for at least a few days. So they get a pass on this one.

But what is really disappointing is that this inverter should never have passed QA from the factory in the first place. I mean, it is 2 volts off in reading the voltage. So when I program the bulk charge voltage at 56V, it might actually be charging at 58V because when the battery is at 58V, the inverter thinks it is at 56V. Another peeve is that I had to spend $10 on a USB to RS232 cable (EG4 only provided the Ethernet to RS232), and $80 on a 60V DC variable power supply to do the calibration. You have to instruct the EG4 to read the battery voltage (power supply) at 55.50 volts and again at 46.0 volts while issuing some commands through the comms cable in order to properly calibrate it. I had to do it fast too because the power supply I got was rated at 100W. At some point the EG4 begins to draw more than 100W during the startup sequence and cause the power supply to overload and shut off. Yes, I made sure that everything was shut off so that there was no load. That's a whole other thread about the EG4 idle current draw.


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How did you get the voltage to read correctly? Would you mind show me how? Thank you so much
 

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