Getting 36 used PV panels, looking for input on how to set them up far from the main PV equipment

[OffGridForGood]

I have made arrangements to take some older Sharp 230W panels from an existing set up that will be getting new PV.
The used panels are Sharp NU-U230F3 modules, I will get 36 identical panels, and I am told these are "about 8 years old". I have a PV tester, and will be able to determine if any are faulty prior to building the ground mount and installing them.
36 x 230W = 8.28kW even if they only output 70% this would be 5.8kW

VOC 37.0
Isc 8.40
Rated Voltage 30v
Rated Current 7.67
Max series voltage 600v
Max series fuse 15A

So the space I have for a ground mount, without shade is pretty darn far from my main ESS - approx 400 ft (122m) one way distance including vertical at ends. This screams high voltage PV to keep the wire size down.
My main ESS is 48v nominal 16s LFP.
What are the suggested SCC, and ##s - ##p combinations to utilize these? Feel Free to consider quantity less than all 36, some may be faulty.

 

[Zwy]

9S four strings, a pair of EG4 MPPT's. You won't find a high voltage MPPT in that price range. If the panels put out 100%, you are still covered and if you decide later to upgrade you can easily replace the panels and use the MPPT's.

You can parallel 2 strings right at one MPPT, that allows you to skimp on wire. Unless you might replace the panels at a later date.

 

[OffGridForGood]

9S four strings,

9s 4p 9x37 = 333v VOC,
4p 4x 7.67A = 30.68A
or with two sets of conductors, 15.34A each x2
Since the EG4 has 22A limit.
An online DC wire size calculator spits out: "8 AWG" - so four conductors of #8.
If I wanted to future proof, to the full 22A of the EG4, at 333v, then wire would be #6 AWG

a pair of EG4 MPPT's. You won't find a high voltage MPPT in that price range.

EG4 500v 100A (on sale for 10 more days at $399USD)
I see the specs for the EG4 allow up to 500v and 22A string

Edit: but appears limited to 5500W

I wonder about using higher voltage to reduce amperage to keep the wire I have to buy lower cost. @timselectric convinced me in another thread that conduits and loose conductors are the way to go especially if future upgrades are likely/inevitable. The conduit line will go half-way and come up in a pull pit beside an outbuilding, then go to the shop where the solar power plant lives.
If I take 15% off the max voltage to allow for cold temps, I get a max design voltage of 435.
435/37v (VOC) would give me 12 panel string as my likely max.

12s 3p = 444v and 23A likely just within the capacity of a single EG4 500v SCC. Maybe some clipping on sunny days? perhaps not with 8-year old used PV panels. An online DC wire ga calculator spits out "7AWG" to carry the full 444v 23 A.

If the panels put out 100%, you are still covered and if you decide later to upgrade you can easily replace the panels and use the MPPT's.

You can parallel 2 strings right at one MPPT, that allows you to skimp on wire. Unless you might replace the panels at a later date.

I am designing the ground mount for larger future panels as this is on my mind: these used panels are likely to be replaced in 5-10 years, with better larger panels.

 

[timselectric]

Highest voltage possible is best.
But don't exceed the VOC limit. And make sure that you calculate cold temperature with a safety margin.

 

[OffGridForGood]

If I read the EG4 manual correctly, this is limited to 5500W
so even if the PV panels are degraded, they will be too much for a single EG4.

I see Midnight Solar have a 600v 30A model. This should be able to carry the whole 36 panels.
Using 500v would be 16.56A, and a single pair of #8 AWG would carry the whole array.
I have to get the manual and see what the limits are, research is the least expensive part of the process.

 

[OffGridForGood]

The Midnite specs are impressive, $2,000 price point thou. love the low standby current.
The other option I see people using, add an AIO just to use it as a SCC - doubles as a back up inverter if needed. $1600 USD plus ship.
Looking at this option, the new "12k" PV inverters (10kW output) being discussed in other threads check some of the boxes:
600v max VOC, 18A per MPPT, 30A total input, but higher standby current.
running these numbers:
12s-3p is 360v 23A on a single pair of 8AWG wire. Saves on wire cost.

Future PV,
If I imagine 10s 600W panel strings, then the system could run two of these, on the two MPPT inputs. Just need to install conduit big enough for the future cable for the second string. Maybe smarter to allow for three.

More research to do.

 

[Zwy]

Use a pair of MPPT's, not a single unit. It will be in place when you do replace those panels. A pair of #8 wires running 400 feet won't be cheap plus down the road you will probably need more wire.

9s 4p 9x37 = 333v VOC,
4p 4x 7.67A = 30.68A
or with two sets of conductors, 15.34A each x2
Since the EG4 has 22A limit.
An online DC wire size calculator spits out: "8 AWG" - so four conductors of #8.
If I wanted to future proof, to the full 22A of the EG4, at 333v, then wire would be #6 AWG

Not 4P strings, 2 strings in parallel at each MPPT. You use small AWG wire until you get to the MPPT's and then parallel the 2 strings right before the MPPT in a junction box.

Go online and price out wire, you will find 8AWG and larger get very costly. I prefer 10AWG as it limits voltage drop, you could use 12AWG and be just fine. You can run 3 12AWG for the same cost as 8AWG over the same distance.

EG4 500v 100A (on sale for 10 more days at $399USD)
I see the specs for the EG4 allow up to 500v and 22A string

Edit: but appears limited to 5500W

Output is 100A so it will never output 5500W. I don't overpanel but see these commonly pull full STC from PV when it is colder with no haze.

I'd panel these around 4500W per MPPT. Seems to work extremely well, the fans will be screaming at peak sun.

I wonder about using higher voltage to reduce amperage to keep the wire I have to buy lower cost. @timselectric convinced me in another thread that conduits and loose conductors are the way to go especially if future upgrades are likely/inevitable. The conduit line will go half-way and come up in a pull pit beside an outbuilding, then go to the shop where the solar power plant lives.
If I take 15% off the max voltage to allow for cold temps, I get a max design voltage of 435.
435/37v (VOC) would give me 12 panel string as my likely max.

12s 3p = 444v and 23A likely just within the capacity of a single EG4 500v SCC. Maybe some clipping on sunny days? perhaps not with 8-year old used PV panels. An online DC wire ga calculator spits out "7AWG" to carry the full 444v 23 A.

I would not do it, one member has a video where he probably over paneled the EG4 MPPT and it failed. I asked about PV but he never responded. Either it was pushed over on VOC on a cold day or he over paneled it and it pulled full load and died. As he did not respond, he most likely was the fault by exceeding limits.

I don't know how well these clip, I don't need to over panel.

As I stated before, 2 strings of 9S per MPPT.

I am designing the ground mount for larger future panels as this is on my mind: these used panels are likely to be replaced in 5-10 years, with better larger panels.

Most larger panels run around 50V for VOC so 9S is probably the limit for most SCC's although we are seeing 600V max VOC but operating range is still below 500V.

 

[Zwy]

The Midnite specs are impressive, $2,000 price point thou. love the low standby current.

EG4 unit has a consumption of 25W and shuts down when the sun goes down.

I told you that it will be impossible to find a high voltage MPPT in the price range of the EG4. $399 is a bargain. I'll be adding a few more down the road possibly but might change plans here and run a power house out of the new garage we are building.

The other option I see people using, add an AIO just to use it as a SCC - doubles as a back up inverter if needed. $1600 USD plus ship.

Standby loss is high.........

$1600 buys 4 EG4 MPPT's. I've been down that road, I thought about that when I had the 6500EX's and replaced them with the LV6548's.

Looking at this option, the new "12k" PV inverters (10kW output) being discussed in other threads check some of the boxes:
600v max VOC, 18A per MPPT, 30A total input, but higher standby current.
running these numbers:
12s-3p is 360v 23A on a single pair of 8AWG wire. Saves on wire cost.

Future PV,
If I imagine 10s 600W panel strings, then the system could run two of these, on the two MPPT inputs. Just need to install conduit big enough for the future cable for the second string. Maybe smarter to allow for three.

More research to do.

If you are moving towards hybrid type inverters, then AC coupling might make more sense.

 

[MTM98290]

Morningstar TS-MPPT-60-600V-48-DB-TR-GFPD Controller

Shop now for Morningstar TS-MPPT-60-600V-48-DB-TR-GFPD Charge Controller Pre-Wired with Ground Fault Protection Device 60A 600VAC 48VDC. Can be used with higher voltage photovoltaic (PV) arrays, select wind turbines, and more.

www.stellavolta.com

This looks like a great way to implement one big array far from the battery. Seems illogically cheap compared to Morningstar's other SCC offerings so I could be missing something.
They can handle 3200w so you would need a few. They can be paralleled. 600V PV/ 60A charging.

There are also Midnite and Schnieder models that handle 600v as well.

The eg4 500v scc's are much more affordable. They are definitely interesting.

 

[Hedges]

Two PV strings in parallel but of different orientation would reduce peak amps and watts.
Use trig for whatever angle, if 90 degrees between them would be 0.7x the peak (remember they have azimuth and orientation, but are just 2 planes with a single angle between them.)

 

[sunsurfer]

I told you that it will be impossible to find a high voltage MPPT in the price range of the EG4. $399 is a bargain.

I bought some "bargain" SCCs once from advice on this forum. Then I replaced them once I figured out they where crap. How fast and reliable are those "bargain" EG4 units compared to known "reliable" and "fast" units?

Half price isn't really half price when they are not fast enough to capture the light between the clouds and they fail or get stuck at a high voltage etc....

Who with experience has tested these EG4s long term? Are they fast? Reliable? Just rebrands? I would love to hear feed back.

 

[rhino]

For more datapoints, I did what you mentioned and got a 18kPV (at a discount) mainly for the solar charge controller and as a backup inverter system since I also have a pair of Victron Quattro 5kVAs. I don't have data to back this up yet but from casual observation it appears the SCC in it is slower then the Victron SCCs I have for other arrays.

I did use aluminum cabling for the Victron 250V SCCs connected to arrays that were over 400ft away. The aluminum was significantly cheaper than copper and was rated for direct burial but also placed in conduit. For conduit I got reels of UL listed HDPE which was a lot cheaper then using PVC conduit.

Most annoying thing I have about going with the 18kPV is the fan noise when you start dumping over 100A to the batteries from the PV array. That's an issue with a lot of these cheaper SCCs. That Morningstar one doesn't even have fans nor does the 250V Victron charge controllers I have on my other arrays.

 

[Zwy]

I bought some "bargain" SCCs once from advice on this forum. Then I replaced them once I figured out they where crap. How fast and reliable are those "bargain" EG4 units compared to known "reliable" and "fast" units?

Half price isn't really half price when they are not fast enough to capture the light between the clouds and they fail or get stuck at a high voltage etc....

Who with experience has tested these EG4s long term? Are they fast? Reliable? Just rebrands? I would love to hear feed back.

I've been running one since mid July, the other since early August. There is a firmware update on mine, later models might not need it. The only problem was in low light in the evening it would set an intermittent code for Bus soft start which was due to the low PV input in the evening. It wasn't a huge issue, the unit would reboot and start up again the next day and work just fine. The firmware completely eliminated that problem.

I'd call in if you want to order this MPPT and see if you will need to update firmware and have the needed cable to install the update included. It is a special patch cable. Firmware update video is here.

I have not had a single problem since. These have worked flawlessly. I am pulling full wattage from PV most days at peak sun.

These will communicate with EG4 batteries, that cable is included. I don't use comm so it didn't matter to me. I know of no other communication with these so you won't be able to pull PV harvest data from the MPPT. One could install a Smartshunt after the units to record PV daily input. I just use daily load and battery charged data from SA.

I did a video on how I installed these and about the code setting, followed by an update and how to update firmware. I was very critical of SS support, they deserved it too. https://diysolarforum.com/threads/e...500vdc-100a-mppt100-48hv-sets-code-f01.68669/ Markus at EG4 pointed me in the right direction.

I would not hesitate to buy these again. I might be actually purchasing more as I expand my system for my shop.

 

[sunsurfer]

I've been running one since mid July, the other since early August. There is a firmware update on mine, later models might not need it. The only problem was in low light in the evening it would set an intermittent code for Bus soft start which was due to the low PV input in the evening. It wasn't a huge issue, the unit would reboot and start up again the next day and work just fine. The firmware completely eliminated that problem.

I'd call in if you want to order this MPPT and see if you will need to update firmware and have the needed cable to install the update included. It is a special patch cable. Firmware update video is here.

I have not had a single problem since. These have worked flawlessly. I am pulling full wattage from PV most days at peak sun.

These will communicate with EG4 batteries, that cable is included. I don't use comm so it didn't matter to me. I know of no other communication with these so you won't be able to pull PV harvest data from the MPPT. One could install a Smartshunt after the units to record PV daily input. I just use daily load and battery charged data from SA.

I did a video on how I installed these and about the code setting, followed by an update and how to update firmware. I was very critical of SS support, they deserved it too. https://diysolarforum.com/threads/e...500vdc-100a-mppt100-48hv-sets-code-f01.68669/ Markus at EG4 pointed me in the right direction.

I would not hesitate to buy these again. I might be actually purchasing more as I expand my system for my shop.

How are they when clouds are rolling through? Do they track in seconds or fractions of a second? I've noticed cheaper MPPTs taking a few seconds to track in between clouds and they miss a ton of light. Might have something to do with less electronic parts needed for buffering in quick burst. Cant have cheaper unless there is less parts/materials to make up the difference or perhaps less engineering.

Next question I would ask, who makes this MPPT for EG4? It might be even cheaper with a different sticker on the front. Not that I would ever buy a lower tier MPPT even though the price is tempting. I'm 100% off-grid so I need to avoid the hobby grade gear.

 

[sunsurfer]

I don't have data to back this up yet but from casual observation it appears the SCC in it is slower then the Victron SCCs I have for other arrays.

That seems to be a common thing and what I have also observed with cheaper MPPTs in general. They are much slower then Victron MPPTs. Some people may not care but for getting every drop of solar on a cloudy day it can make a big difference.

I don't have experience with other tier one units but Victron is fairly fast for the price from what I see.

 

[Zwy]

How are they when clouds are rolling through? Do they track in seconds or fractions of a second? I've noticed cheaper MPPTs taking a few seconds to track in between clouds and they miss a ton of light. Might have something to do with less electronic parts needed for buffering in quick burst. Cant have cheaper unless there is less parts/materials to make up the difference or perhaps less engineering.

As you asked, I shall link it for you. https://diysolarforum.com/threads/5...-unless-youre-some-kind-of-solar-freak.75746/ Be sure to watch all of it as the clouds roll thru. That will answer those questions.

Edit: The video shows each MPPT which has 4.24 Kw of panels per MPPT.

Next question I would ask, who makes this MPPT for EG4?

Don't know but it works very well.

It might be even cheaper with a different sticker on the front.

You can search but you won't find a 500V rated MPPT for that price.

I had just been thru the 6500EX fiasco and was very hesitant on purchasing anything more from SS. I searched for a higher voltage MPPT for some time, but you will not find one at this price point. It is a basic unit, nothing fancy which suits me just fine. It just makes power.

Not that I would ever buy a lower tier MPPT even though the price is tempting. I'm 100% off-grid so I need to avoid the hobby grade gear.

Yesterday morning was no clouds on the horizon unlike this morning for an hour until the sun climbed high enough. By 7:40 AM, I was charging batteries and fully powering 1.7 Kw of loads from PV. Array size is 8.4 Kw. These wake up at first sun and will pull off PV as soon as PV can produce.

In one week I will have ran my house off grid over 97% off PV. We used 254 Kwh from the grid during the 4 weeks of December/January with no sun. Total this far is 8319.374 Kwh for the year with one week to go. Plus I saved 400 gallons of propane using excess PV as a heating dump load.

 

[OffGridForGood]

EG4 unit has a consumption of 25W and shuts down when the sun goes down.

I told you that it will be impossible to find a high voltage MPPT in the price range of the EG4. $399 is a bargain. I'll be adding a few more down the road possibly but might change plans here and run a power house out of the new garage we are building.

Yeah, you did! LOL but I gotta do the reseach myself, it is in my nature.

Standby loss is high.........

$1600 buys 4 EG4 MPPT's. I've been down that road, I thought about that when I had the 6500EX's and replaced them with the LV6548's.


If you are moving towards hybrid type inverters, then AC coupling might make more sense.

No, not interested in the Hybrids, but if I could find a pair of 12kW (output) newer models I would swap out my inverters with two newer units - like two birds with one stone. Use the 6048's for some remote locations, portable 120/240 units. No-one makes a 12kW output AIO in 120/240 that I have seen. Two ten's don't give me anything more than I have now, other than taking up less wall space.
I do like the low stand-by in the EG4's as you noted. Winter can be a killer as it is, don't need more cloudy day losses.

This seems strange but what are people using for all these ground mounts that are hundreds of feet away from the main ESS, surely there are other 600v 30-40A SCC's out there without buying an AIO just to work as a SCC? No?

 

[42OhmsPA]

I don't have any experience with the EG4 MPPTs.
For the price of just the MPPT I'd spend a little more and buy a 'budget' AIO or 2...
You can likely get a 230VAC version for the same price as the mppt. Here's a used one cheaper. https://www.amazon.com/PowMr-Inverter-220-230V-Controller-Lead-Acid/dp/B0BW3TD4QB

Edit - didn't read your latest reply before posting.

 

[OffGridForGood]

I'd call in if you want to order this MPPT and see if you will need to update firmware and have the needed cable to install the update included. It is a special patch cable. Firmware update video is here.

They can't be sending these out without the updates done for the customer?! wouldn't that just result in flooding the service staff with calls for the same problem over and over?

I have not had a single problem since. These have worked flawlessly. I am pulling full wattage from PV most days at peak sun.

Wow, after the SS/EG4 6500's and then issues with the EG4 SCC's, you have been through a rough one. Glad to hear these SCC are going strong since the update.

 

[Zwy]

Yeah, you did! LOL but I gotta do the reseach myself, it is in my nature.

If you find one cheaper that is reliable, let us all know.

No, not interested in the Hybrids, but if I could find a pair of 12kW (output) newer models I would swap out my inverters with two newer units - like two birds with one stone.

A pair of 18Kpv or Solark 15K?

Both have bugs/features I don't need. I just need something that produces power without internet connectivity (have what I need with SA), allows full access to all settings, doesn't need battery communication, doesn't need to grid tie. It just needs to power high surge loads and not consume many watts when idling.

Use the 6048's for some remote locations, portable 120/240 units. No-one makes a 12kW output AIO in 120/240 that I have seen. Two ten's don't give me anything more than I have now, other than taking up less wall space.
I do like the low stand-by in the EG4's as you noted. Winter can be a killer as it is, don't need more cloudy day losses.

This seems strange but what are people using for all these ground mounts that are hundreds of feet away from the main ESS, surely there are other 600v 30-40A SCC's out there without buying an AIO just to work as a SCC? No?

A recent post by a member was boasting his Victron charge controllers could input 15% more watts per day than the EG4 6500EX's he had before switching to Victron.

Of course it would, the 6500EX was limited to 4 Kw input (actually 3.9 Kw because I owned a pair and it would never exceed 3.9 Kw) on a MPPT while the Victron can do 4500W on the MPPT.

600W divided by 4,000 = 15%