MPP pip 3048LV not seeing panels

mackadoo

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Joined
Nov 26, 2021
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12
Hi all. I've been lurking here for a while but now that I have my system installed I have a real head scratcher that I can't figure out.

I've installed two MPP Solar 3048 units in parallel along with my new Lifepo4 16s 280ah 48v battery system. I had some trouble but I've got the battery charging off the generator (we're fully off grid) but my existing solar panels are not registering somehow.

I have 6 old Sharp panels rated 21.78Voc wired in series and I'm measuring 130-140Voc with my multi meter at one of the MPP units but the unit display says the PV input is intermittently 0V, 4V, or 38-41V. I moved the string over to the second MPP unit with the same results. I've gone through every setting on the MPP and I'm pulling my hair out trying to figure this out.

I have 12 new panels to install come spring time but that will require some construction for supporting the panels, so I need these working over this winter. Any help would be appreciated.
 

mackadoo

New Member
Joined
Nov 26, 2021
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12
Sounds like a bad connection issue.

Maybe try it with just a couple panels which would be fewer connections. Try a couple different pairs.
I've now gone through a few permutations and bypassed my PV combiner. Even one panel, reading 20Voc on my meter at the MPP is giving me 0V on the unit display. Tried with 4, then 2 panels before trying with the 1 and always similar results.
 

mackadoo

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Nov 26, 2021
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I'm on really poor 3g service and the upload isn't quite liking it. Really there's not much to picture - I go from PV +- on the MPP to a disconnect, from the disconnect outside to the shed with a PV combiner, up to the panels (in this case, just one now). I've now bypassed the combiner and the disconnect with wire nuts to have it straight through. My tester reads 20v and the unit reads 0v.
 

mackadoo

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Nov 26, 2021
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I've gone back through the connections at each of the panels. As the sun is setting I'm getting 120V on my tester and 4V on the MPP display. I'm taking my neighbours advice of "Drink a Scotch and sleep on it. Better yet, make it a double."
 

mackadoo

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Nov 26, 2021
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Coming back to things this morning... The issue is not with the panel wiring which I can guarantee by an accidental arc flash about an inch and a half long from the wires that go into the MPP when I was trying to rewire something. I'm at a complete loss as to why the MPP unit is only reading a few volts on the display.



I've gone through the menu over and over again - is there some setting that I keep missing that turns off solar charging entirely? I'm at wits end here.
 

MisterSandals

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Nov 5, 2019
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accidental arc flash about an inch and a half long from the wires that go into the MPP
So you plugged a fully energised array into your SCC and go this arc?

Or was this plugging batteries into your SCC? There are known capacitor inrush problems with this that should be mitigated with precharge.

Now thinking this arc might have toasted something.
 

OffGridInTheCity

Solar Addict
Joined
May 23, 2021
Messages
796
Location
Southern Oregon
I have a working MPP Solar 3048 in my trailer - with 4 x 300w panels wired in as 2s2p. A couple of things come to mind - you'll notice that at 8am on a winter day I also have 0 watts :)

1) Notice that at 2s, my operating voltage below (65.3v) is higher than the max voltage of my 48v battery. If this is lower, it could result in 0 watts.
2) Notice I have 0 watts - this is due to low sun/shading. Are you sure all your panels are in the sun? or at least 1 string is 100% in sun?
3) Sorry question - is the battery 100% charged perhaps?
4) Sorry question - has the unit ever worked?
----- more complicated ------
5) I don't understand all the ins/outs of the "Charge source priority" + "Output source priority" settings - and the wrong settings could render your watts = 0. Mine below of "SBL&UCB" + "Utility->Solar->Battery" work with or without shore power plugged in. Maybe try my settings?


Here are my settings - that work with/without shore power plugged in.
Note: I have the 14s lithium-ion battery at 53.2v = 3.77/cell on purpose to go easy on the batteries when the camper is just sitting.
1638028909318.png

Here's 8am (winter) view of the operating info:
1638028969610.png
 

mackadoo

New Member
Joined
Nov 26, 2021
Messages
12
I have a working MPP Solar 3048 in my trailer - with 4 x 300w panels wired in as 2s2p. A couple of things come to mind - you'll notice that at 8am on a winter day I also have 0 watts :)

1) Notice that at 2s, my operating voltage below (65.3v) is higher than the max voltage of my 48v battery. If this is lower, it could result in 0 watts.
2) Notice I have 0 watts - this is due to low sun/shading. Are you sure all your panels are in the sun? or at least 1 string is 100% in sun?
3) Sorry question - is the battery 100% charged perhaps?
4) Sorry question - has the unit ever worked?
----- more complicated ------
5) I don't understand all the ins/outs of the "Charge source priority" + "Output source priority" settings - and the wrong settings could render your watts = 0. Mine below of "SBL&UCB" + "Utility->Solar->Battery" work with or without shore power plugged in. Maybe try my settings?

Thanks for this. My problem isn't that I'm not getting any watts through (although that's the next step) it's that the unit isn't detecting any voltage from the panels.

I'm at a pretty remote cottage and I didn't even think to bring computer, I've been doing all my settings on the unit's screen directly, but my settings look similar.
 

mackadoo

New Member
Joined
Nov 26, 2021
Messages
12
After everything, I connected my panels to my second MPP unit again and it works! Maybe I just didn't give the mppt tracker enough time previously to figure itself out. Looks like the other unit is somehow faulty, luckily it's not super critical I have them both running right now. I'll post back here once I get a resolution from MPP.

Thanks for the input MisterSandals and OffGridInTheCity.

Getting this going has been one headache after another. I'll post here my problems and solutions for future Googlers.

First, of the two packs worth of cells I ordered (32 cells to run two 16s 48v batteries with separate BMS in parallel) a single cell leaked in transit. It measures ok open circuit but the BMS panics on charging it so I've just put in a ticket with the AliExpress vendor to get it replaced.

Second, neither of my 3048 units wanted to charge from the generator. After much gnashing of teeth I realized my generator was running a little fast, between 63 and 65HZ, which was fine on the previous system but not for the MPP units. A little browsing on YouTube showed me how to adjust the throttle to lower the frequency on the generator around 59-61HZ and that got things going.

Third was this problem here. Glad to have it sorted as this is an of grid cabin in Ontario and the power generated by the unit has to be enough to warm the insulated box the batteries are in to keep them above freezing. I took a week off work to get things going and got this figured out just in time to go home.

I guess the moral of the story is "Hurrah for redundancy."
 
Last edited:

TomC4306

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Joined
Mar 2, 2021
Messages
286
I think the motto is if it's going to be installed in a remote location, build it at home and get it working first and then transport to the location and install it.

Edit. Or maybe the moral of the story..
 
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