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MPP LVX-6048 x3. So many problems. (wrong battery voltage, floating neutrals, grid feedback failing)

nickwoz

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Oct 25, 2021
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So here was my plan: Have 3 LVX-6048s connected in parallel in order to be able to run my house totally off-grid. I have 2 EVE 48v 280AH DIY batteries connected to copper bus bars both run by overkill solar BMS's. The battery busbars are to ensure equal voltage to all MPP units. From there I have equal length cabling to the all-in-ones so they read the same voltage.

From the beginning one of the units (now known as unit 2) would not feedback to the grid - it saw the incoming voltage and would signal like it was going to provide grid feedback, but it never actually kicked on.

Fine I thought - my plan is to run off-grid anyways, so I turn off grid feedback on all the units. Now they are hooked up in parallel as shown in the manual, and they run just fine, with one unit (unit 1) sometimes reading slightly lower voltage than the others. Weird I think, but maybe it's because the majority of the solar is coming into unit 3, and I have some shading in the mornings on the string going into unit 1. Fast forward about 3 months and now the unit is throwing 'battery voltage low' regularly. When it does throw the error, unit 1 turns off and stops producing power... BUT THE OTHER UNITS DON'T!!! Now, this leads to all sorts of issues in my house. Every one of my (15+) AFCI breakers are ruined since now the other units are only producing what they think are 2/3's of the load. After replacing with standard breakers, whenever this happens my house voltage is ALL OVER THE PLACE - this has blown out several light bulbs as well as my coffee maker. After over a month of trying to get support from MPP, they send a program for me to try and re-program the voltage reading of unit 1 so it doesn't do this. The problem? You need a serial port... this is 2022, Microsoft Windows PCs essentially removed the legacy COM ports. But on top of that, the majority of the time unit 1 is reading the proper voltage on the batteries and matches within 1 volt or so the other two units. It eventually got worse where it couldn't read proper voltage for more than about a minute or two and then it would drop from say 53 volts to 34 volts, and kick off.

Pissed off at the lack of support, I decided I would just run off the other two units until I figured out what the problem truly was. So I re-work the parallel cabling for just 2 units and find out now I have a floating neutral. I try running on both units (2 & 3) individually - the same result. So now THEY are both broken.

As a last-ditch effort I think, well, I can use unit 3 to provide grid feedback as it just provides 240v, and doesn't feed individual split phases. Now it kicks on and provides grid feedback, but for about 20-30 seconds and kicks off, only to kick back on again. (I know this cause I can hear the click of it turning off and the *thwonk* of the inverter turning back on, as well as my utility meter's real-time app, matching what I can hear).

Now I have 3 bad units, multiple issues (probably) with each. Is there ANYWHERE in the states that I can turn to for support? Emailing Taiwan is a pain-staking process that so far hasn't yielded any help, and it seems that I need parts to fix these things and I'll bet anything I'll never see correct replacement parts from MPP shipped from Taiwan.

I purchased MPP products since Will uses/recommends them and also states these all-in-one units ARE serviceable. I am truly out over $6000 and will have to go with other companies just to get back on solar?

Any help AT ALL is appreciated.

(also, I know the wiring is right - I'm an industrial field commissioning electrical engineer and know not to energize without
testing every wire and phase more than once before throwing breakers.)

edit: provide more clarity & spelling corrections
 
I believe watts247 stocks some replacement boards for these; might want to hit them up & see if they've any ideas. Sounds like you've done your homework, so hopefully not too bad to figure out what needs to be swapped.

So far I've had a much better experience with these lvx boxes (two in parallel, entirely off-grid) with the exception of random restarts every few days. I will say, there does *not* appear to be any built-in ground-neutral bond, which presents a challenge for grid-tie (which I'm not doing but you're trying to do); as you found, you'll easily end up with a floating neutral when the grid connection drops and that... Just plays hell with everything. If you can bond downstream of the inverters, they seem happy enough.

FWIW, you can pick up usb->serial dongles on Amazon, Newegg, etc. for a few bucks a pop; worth having a few around.
 
Oh man. This sounds like a terrible experience. I am no expert, but installed (2) Solaredge inverters before installing the LVX-6048 recently. There is definitely something about the grounding of the LVX unit that requires some kind of extra procedure. All of my grid-tied inverters' neutrals are tied to ground because they go straight to the main panel(s), but an error on my part in forgetting to ground the solar panels connected to the LVX before turning it on resulted in an AC voltage between the panels/racking, and my metal building. The entire building is grounded. Once I grounded the racking to the building, the AC voltage went away. But how the solar panels had an AC voltage running through them is a mystery to me.

I hope you get some support soon!
 
Ian at watts247 does not stock boards, but he can make mpp Taiwan ship you one quick. I had to replace my main board in my LV6548.

Where did you buy them?
 
I know two batteries are insufficient, so plan on at least trippling that.
 
Could you provide a list of your settings in your MPP LVX-6048? It would be good to also have a single line diagram so we can consider modifications to better balance your system's Voltages.
 
I believe watts247 stocks some replacement boards for these; might want to hit them up & see if they've any ideas. Sounds like you've done your homework, so hopefully not too bad to figure out what needs to be swapped.

So far I've had a much better experience with these lvx boxes (two in parallel, entirely off-grid) with the exception of random restarts every few days. I will say, there does *not* appear to be any built-in ground-neutral bond, which presents a challenge for grid-tie (which I'm not doing but you're trying to do); as you found, you'll easily end up with a floating neutral when the grid connection drops and that... Just plays hell with everything. If you can bond downstream of the inverters, they seem happy enough.

FWIW, you can pick up usb->serial dongles on Amazon, Newegg, etc. for a few bucks a pop; worth having a few around.
I agree, MPP Solar support Sucks....
 
I agree, MPP Solar support Sucks....

speaking totally about MPP CHINA -- I do have to lean toward agreeing with you ... it makes no sense -- they go out of their way to market a good product ... and for 95% of the time everything works fine -- but that 5% of ppl with issues or questions they simply get blown off ... what they don't understand is that those 5% are voicing their concern and thats stopping allot of ppl from buying more MPP products ...

I know its not a language barrier because when i have called them several times speaking Chinese it actually turns to English being easier (sure my Chinese sucks) ... I just think that the issue is that MPP does not have a full time dedicated support staff to answer issues -- all they are focused on is sales sales sales ...
 
I believe watts247 stocks some replacement boards for these; might want to hit them up & see if they've any ideas. Sounds like you've done your homework, so hopefully not too bad to figure out what needs to be swapped.

So far I've had a much better experience with these lvx boxes (two in parallel, entirely off-grid) with the exception of random restarts every few days. I will say, there does *not* appear to be any built-in ground-neutral bond, which presents a challenge for grid-tie (which I'm not doing but you're trying to do); as you found, you'll easily end up with a floating neutral when the grid connection drops and that... Just plays hell with everything. If you can bond downstream of the inverters, they seem happy enough.

FWIW, you can pick up usb->serial dongles on Amazon, Newegg, etc. for a few bucks a pop; worth having a few around.
Newbee to all this and trying get up to speed for my 2 LVX6048 install.
Question; I DO NOT want to feed back to the grid but have AC in from the grid (my main), is that "off-grid" or "grid tied"?
I was not planning to bond past my inverters (or have another ground rod), thinking that my AC-in was bonded at the main and connected to the one ground rod for the utility. Again...I am very new and have never installed anything like this. So any other do's and don't do's are appreciated. Thanks
 
Question: I DO NOT want to feed back to the grid but have AC in from the grid (my main), is that "off-grid" or "grid tied"?
I would consider that grid tied, but definitions vary. Usually when I hear grid tied, I think back feed, but the two words literally mean tied to the grid. If you are using grid power into the unit, you are grid tied. Off grid would be off grid (not connected to the grid), but I can't tell you how many times I have read on this forum "Hey I am off grid, but my grid connection is acting funny"... :rolleyes:

Off course the other definition is what happens to your system if the grid goes down? If it still works, you are off grid. If it doesn't work, you are grid tied. YMMV...
 
I would consider that grid tied, but definitions vary. Usually when I hear grid tied, I think back feed, but the two words literally mean tied to the grid. If you are using grid power into the unit, you are grid tied. Off grid would be off grid (not connected to the grid), but I can't tell you how many times I have read on this forum "Hey I am off grid, but my grid connection is acting funny"... :rolleyes:

Off course the other definition is what happens to your system if the grid goes down? If it still works, you are off grid. If it doesn't work, you are grid tied. YMMV...
Thanks. I guess the devil is in the the details as far as accurately defining the system. So, I am going to have a grid-tied/non-feedback system. Am I on the right track for the ground/neutral bond and the one ground rod all being back at the main service panel only?
 
My LVX6048s are sitting on my living room floor holding down the carpet, so I have no practical experience yet, but that was how I was planning on doing it as well.

The four scenarios I can think of are:

1. Connected to Grid which is feeding the inverter. Hot/Neutral/Ground all pass through from Main panel?
2. Connected to Grid, but no power feeding the inverter. Ground passes through?
3. Connected to Grid, but Grid is down (no power). Ground passes through?
4. Not connected to grid at all. Not sure where ground would come from.
 
My LVX6048s are sitting on my living room floor holding down the carpet, so I have no practical experience yet, but that was how I was planning on doing it as well.

The four scenarios I can think of are:

1. Connected to Grid which is feeding the inverter. Hot/Neutral/Ground all pass through from Main panel?
2. Connected to Grid, but no power feeding the inverter. Ground passes through?
3. Connected to Grid, but Grid is down (no power). Ground passes through?
4. Not connected to grid at all. Not sure where ground would come from. I use a grounding rod for my ground.
 
speaking totally about MPP CHINA -- I do have to lean toward agreeing with you ... it makes no sense -- they go out of their way to market a good product ... and for 95% of the time everything works fine -- but that 5% of ppl with issues or questions they simply get blown off ... what they don't understand is that those 5% are voicing their concern and thats stopping allot of ppl from buying more MPP products ...

I know its not a language barrier because when i have called them several times speaking Chinese it actually turns to English being easier (sure my Chinese sucks) ... I just think that the issue is that MPP does not have a full time dedicated support staff to answer issues -- all they are focused on is sales sales sales ...
I am not impressed with Mpp Solar tech support either seem they just resale a voltronics box painted yellow.The app shows the voltronics model not LVX6048
 
So I am seeing here:
-a battery voltage calibration loss driving the charger wrong over 3 months
-the neutral/ground bond needs to be gone
-serial to usb should be supplied

Pls add to this list
Also to make sure there is no BMS comms setup right?

Is the firmware updated to the latest? What is the versions on the units you have currently?

@BenFromSignatureSolar will be interested in replicating these scenarios at the r+d lab
 
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I purchased 2 LVX6048WP last year and began starting them up in October. One of the inverters developed a problem within a few weeks, the other inverter has run without trouble, in off- grid mode and then in grid tied mode.
There is a difference between the two inverters that I didn't know about until after the problems began. The problem inverter is slightly older and has to be updated with different firmware than the newer inverter.
I am working with MPP to try and bring the inverter back to life. It's slow going and there is a bit of a language barrier but sometimes you run into that with people born speaking English.
So far MPP has sent me replacement boards for everything but the communications board and display. The inverter starts up runs for about 50 seconds and shuts off. The display doesn't come on at all. I can set the wifi up but it doesn't connect to the SolarPower ap. I can also start downloading firmware through rs232 but the unit shuts down while downloading.
I'm hoping that MPP sends a comm board.
 
So I am seeing here:
-a battery voltage calibration loss driving the charger wrong over 3 months
I know this is an old thread, but do you happen to know which LVX6048 board monitors battery voltage? One of my units just started reading voltages all over the place. It started doing this shortly after I tried hooking up the Lifepower4 communications hub (which I may or may not be related). The day after hooking up the comm hub, there was a smell of cooking electronics, but it went away pretty shortly. Sometimes electronics will smell the first time they are used, but in this case, I am guessing something cooked (but apparently not catastrophically). In the last couple of days it has been reading anywhere from -2 to +6 volts, which causes the solar to cut out since it thinks the battery is fully charged. I unhooked the communication hub, but no change.
 
Hooked up my second array to the LVX today (x9 Jinko 325W Mono). Holy crap it is loud(er)! I thought pushing 40amps to the batteries was loud, but 80+amps is insane. I think between the two inverters I peaked at 127amps today. Ironically, now when the LVX is at 30-40 amps, it is much quieter (still noisy, but better). I am not sure if the fans are controlled by heat, or by the amount of power coming in (proactively assuming heat is building).

UWKI7293.jpg
 
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