Is this wired correctly? What's going on in the white box?

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cinderblock63
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My RE system: VFX3524

Is this wired correctly? What's going on in the white box?

Post by cinderblock63 »

I have taken over a solar system that someone else installed. I've already found a number of improper ground/neutral bonding points as well as improper use of conduit and romex. Now that I've added some breakers and a distribution panel, I need to figure out what's happened with the inverter/charger/battery setup. I've also got some general questions about the system that I'm hoping someone here might be able to point me in the right direction.

Here's the main part of the system:

Image

Ignore the wasp nests...

I've found the documentation for the VFX3524.

My first bit of confusion is with how the AC Input and Output are wired. It looks like only "AC IN" is connected and nothing connected to "AC OUT".
Image
This system works, as in I can run the well pump from the batteries. Not sure how the power is getting "out" of the inverter if it's wired wrong like I'm thinking it is. Maybe they got lucky with the internal wiring on the inverter/charger?

Next, I'm not finding any information about the white box that the unit is mounted on. I'm guessing it is just a distribution panel for AC and DC parts of the system because I see the large gauge battery terminals and AC terminals going into the box. It also has breakers on the side for main battery disconnect and a number of other 65A breakers. One pair has a metal sliding plate so that they always move together. I presume these are the disconnect & bypass breakers that I've seen in the VFX3524 manuals.

Of course none of the AC wiring leaving this box is sized properly for 65A breakers...

It's also not clear how I would get into this white box. Do I need to remove the VFX3524?

Adding to my confusion are these large capacitors that are on the white box. Does anyone know what these are?
Image

Thank you for taking a look! Cheers!
Last edited by cinderblock63 on Tue Aug 25, 2020 4:16 pm, edited 1 time in total.
BruceS
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6 X 250w X 24V panels ... Outback Inverter 24V X 3Kva (VFX3024E) ... Conext MPPT 60 150 solar controller .... Honda EU6.5i generator (manual start) ... 12 X 2V @ 600Ahr Sonnenschein Batteries ... Shore power facility ... Auto changeover between inverter/shore & genny.
Location: Mannum, Sth Australia, 5238

Re: Is this wired correctly? What's going on in the white box?

Post by BruceS »

Can you take out the two screws & remove that clear cover so we can see the wires under it?
cinderblock63
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Joined: Tue Aug 25, 2020 2:28 pm
My RE system: VFX3524

Re: Is this wired correctly? What's going on in the white box?

Post by cinderblock63 »

Unfortunately I am not at the system right now and cannot be until at least this weekend.

What I remember, from memory of 3 days ago, is that the black and white wires that can be seen go into the leftmost screws terminals. There is also a ground wire connected.

Edit: looking at this picture, I'm not sure if I'm seeing a black wire going into the AC HOT IN or not. I feel like I would have remembered that detail. I'll see if I can't get someone to get a clearer picture before this weekend for me.

Thank you for taking a look!
fcwlp
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My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Is this wired correctly? What's going on in the white box?

Post by fcwlp »

cinderblock63 wrote: Tue Aug 25, 2020 2:58 pm I've already found a number of improper ground/neutral bonding points as well as improper use of conduit and romex.
Welcome and you are ahead of the game in knowing about improper bonding of grounds and neutrals. Don't forget the N-G bond that may be present in the generator.

I think your Inverter and FM60 (most likely) CC are mounted on a Midnite Solar e-Panel. Take a look at this page and see if you can find a match. http://www.midnitesolar.com/products.ph ... %20Outback
cinderblock63 wrote: Tue Aug 25, 2020 2:58 pm Adding to my confusion are these large capacitors that are on the white box. Does anyone know what these are?
This looks like a Delta surge protector, picture at https://www.galesburgelectric.com/delta ... gI-QvD_BwE. Their website is at http://www.deltala.com but I have never seen a website with so few pictures. They also have surge protection capacitors.

Now to the more interesting topic of AC In versus AC Out. A couple of questions and/or observations:
1) Is the system setup for off-grid use or do you have grid available?
2) In the picture of the overall inverter & CC it looks like the AC In LED is lit.
3) How did you confirm that the well pump ran off of battery power?
4) Could the well pump be a DC pump running directly off of the batteries?
5) The AC loads must be connected with a dedicated sub-panel that is connected to the AC Out terminals.

FYI, it looks like you have a few mud daubers to also deal with.
cinderblock63
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My RE system: VFX3524

Re: Is this wired correctly? What's going on in the white box?

Post by cinderblock63 »

fcwlp wrote: Tue Aug 25, 2020 4:54 pm Welcome and you are ahead of the game in knowing about improper bonding of grounds and neutrals. Don't forget the N-G bond that may be present in the generator.
Yep. I'm pretty well versed in how electrical systems work. I've designed smaller DC solar systems and variable frequency motor drives. I just don't have a lot of practical experience in solar deployments. Love that the internet lets us all share our expertise.

If memory serves, the generator does not have a ground-neutral bond.
fcwlp wrote: Tue Aug 25, 2020 4:54 pm I think your Inverter and FM60 (most likely) CC are mounted on a Midnite Solar e-Panel. Take a look at this page and see if you can find a match. http://www.midnitesolar.com/products.ph ... %20Outback
Those certainly look right. I'll have to look closer next time I go. That there is a door that might be able to just swing open is a good sign. I'll look for the latch I missed.

fcwlp wrote: Tue Aug 25, 2020 4:54 pm This looks like a Delta surge protector, picture at https://www.galesburgelectric.com/delta ... gI-QvD_BwE. Their website is at http://www.deltala.com but I have never seen a website with so few pictures. They also have surge protection capacitors.
Aha! That could be it too. Might be one of each?
fcwlp wrote: Tue Aug 25, 2020 4:54 pm Now to the more interesting topic of AC In versus AC Out. A couple of questions and/or observations:
1) Is the system setup for off-grid use or do you have grid available?
No grid power available.
fcwlp wrote: Tue Aug 25, 2020 4:54 pm 2) In the picture of the overall inverter & CC it looks like the AC In LED is lit.
I agree.
fcwlp wrote: Tue Aug 25, 2020 4:54 pm 3) How did you confirm that the well pump ran off of battery power?
Generator was off. Turned a switch on that was labeled "from solar" and pump turned on. Measured ~15A on 110V circuit. Battery level drops.
fcwlp wrote: Tue Aug 25, 2020 4:54 pm 4) Could the well pump be a DC pump running directly off of the batteries?
Definitely not. It is ~100 feet from the batteries and there is a single conduit of romex from solar to the pump shed. It is a 240V pump running via an "Auto Transformer" (PSX-240). It is a 1:1 coil hooked up to generate a second phase 180 degrees off from the first, resulting in a 220VAC/2-phase output that goes into the pump (which does not use a neutral). This was where most of the improper neutral/ground bonding was happening. To make this setup more complicated, the generator is hooked directly up to the pump (via L14-30, if memory serves, plug, with a cable that is missing a neutral... ugh) and it was common at this site to just leave the switch that connected the transformer's 110V input to the solar in the off position. I don't know what would have happened if someone plugged in a generator and had the solar switch on... At a minimum some popped breakers I presume... not sure if this ever accidentally happened. Also the plug going to the generator is then hot when the switch is on. This is super unsafe and one of the reasons I insisted on redoing the wiring in the pump shed. I'm looking forward to getting a transfer switch or two in there so that this stuff is always safe. But that's a different part of the project...
fcwlp wrote: Tue Aug 25, 2020 4:54 pm 5) The AC loads must be connected with a dedicated sub-panel that is connected to the AC Out terminals.
Yeah, I think this was mostly skipped. I don't see any breakers near the solar system (or installed anywhere) besides the 65A breakers on the side of the big white box... The other impetus for this particular project.
fcwlp wrote: Tue Aug 25, 2020 4:54 pm FYI, it looks like you have a few mud daubers to also deal with.
I cropped the picture too. There are soooo many. 😢😢😭😭😭
fcwlp
Forum Czar
Posts: 792
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Is this wired correctly? What's going on in the white box?

Post by fcwlp »

cinderblock63 wrote: Tue Aug 25, 2020 8:44 pm fcwlp wrote: ↑
Tue Aug 25, 2020 4:54 pm
This looks like a Delta surge protector, picture at https://www.galesburgelectric.com/delta ... gI-QvD_BwE. Their website is at http://www.deltala.com but I have never seen a website with so few pictures. They also have surge protection capacitors.

Aha! That could be it too. Might be one of each?
There is probably a DC one on the PV input an AC one that should be on the AC Out.
cinderblock63 wrote: Tue Aug 25, 2020 8:44 pm and it was common at this site to just leave the switch that connected the transformer's 110V input to the solar in the off position. I don't know what would have happened if someone plugged in a generator and had the solar switch on... At a minimum some popped breakers I presume... not sure if this ever accidentally happened.
Just make sure not to not run the generator into the AC Out. That will cause bad things to happen inside the inverter. It happened to a customer that I acquired after the initial installer implemented what could be called a less than fool-proof transfer mechanism.
cinderblock63 wrote: Tue Aug 25, 2020 8:44 pm fcwlp wrote: ↑
Tue Aug 25, 2020 4:54 pm
5) The AC loads must be connected with a dedicated sub-panel that is connected to the AC Out terminals.

Yeah, I think this was mostly skipped. I don't see any breakers near the solar system (or installed anywhere) besides the 65A breakers on the side of the big white box... The other impetus for this particular project.
Installing the sub-panel is your next project. You know what to do.

The 65A breakers are likely only for the PV input and CC output. There should also be a 175A breaker between the battery bank and the inverter. If you have a Midnite e-panel their is a space for this large breaker.

I have no idea how the system is delivering power out of the AC In terminals. As the terminals are soldered to a PCB the previous owners could not have swapped the AC In and AC Out functions.

Keep an eye on this topic viewtopic.php?f=1&t=15411. @raysun is going to be measuring the AC In on his system which is similar to your system.
cinderblock63
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Joined: Tue Aug 25, 2020 2:28 pm
My RE system: VFX3524

Re: Is this wired correctly? What's going on in the white box?

Post by cinderblock63 »

fcwlp wrote: Tue Aug 25, 2020 9:55 pm There is probably a DC one on the PV input an AC one that should be on the AC Out.
I think that's it. I think I read "capacitor" on the bottom one and assumed the top was the same. This make total sense (at least they did one part well!).
fcwlp wrote: Tue Aug 25, 2020 9:55 pm Just make sure not to not run the generator into the AC Out. That will cause bad things to happen inside the inverter. It happened to a customer that I acquired after the initial installer implemented what could be called a less than fool-proof transfer mechanism.
Here is what I'm planning for a transfer station, using manual ON-OFF-ON DP switches, in case you're curious.

Image

Unfortunately I cannot move the generator closer to the solar and a cable run to the solar box is too expensive so I can't take advantage of using the inverter's built in bypass/charger & autostart.
fcwlp wrote: Tue Aug 25, 2020 9:55 pm Installing the sub-panel is your next project. You know what to do.
Yep. Right after clearing the mud daubers.
fcwlp wrote: Tue Aug 25, 2020 9:55 pm The 65A breakers are likely only for the PV input and CC output. There should also be a 175A breaker between the battery bank and the inverter. If you have a Midnite e-panel their is a space for this large breaker.
Yeah, there are two linked breakers (with a (loose!) metal plate) next to a 65A breaker. I think this is the main AC input bypass transfer switch that isn't used at all because no shore power. I used this to disconnect the output to work on the rest of the system.

There are also, if memory serves, 4 other 65A breakers. Those could be for the solar panels.

There is also a massive "battery disconnect" switch. I presume this is the 175A you reference.
fcwlp wrote: Tue Aug 25, 2020 9:55 pm I have no idea how the system is delivering power out of the AC In terminals. As the terminals are soldered to a PCB the previous owners could not have swapped the AC In and AC Out functions.
A better picture is forthcoming. Then we will know. I'll be able to open the box up when I go as well. Unfortunately, that has probably been pushed to next weekend. Whee!
fcwlp wrote: Tue Aug 25, 2020 9:55 pm Keep an eye on this topic viewtopic.php?f=1&t=15411. @raysun is going to be measuring the AC In on his system which is similar to your system.
Thanks!
fcwlp
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Posts: 792
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Is this wired correctly? What's going on in the white box?

Post by fcwlp »

Your 3-line looks good given the location limitations on wiring the generator to the inverter. You should consider adding a generator at some point to for battery charging. I understand what you are doing with the auto-transformer input (running 120V from inverter or 240V from gen). I have not done this setup but if it is working from previous install, the existence proof is there.

The massive battery disconnect switch is the 175A I was referring to. It may also be a 250A breaker as that is what Midnite recommends for the VFX3524.
jnh
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My RE system: GVFX-3524, FM-80+FM-60, ~4.9kW PV in mixed panels on movable platforms, 415 Ah AGMs @ 24V, 80Ah @ 12V, Hub4, Mate, FNDC, Brultech GEM 32-ch AC datalogger, Midnite E-Panel, homebrew DC-DC crossfeed to 12V system, Honda EU-1000i, AIMS CON120AC1224DC charger
Location: St. Augustine, FL, US

Re: Is this wired correctly? What's going on in the white box?

Post by jnh »

To open an E-panel, remove 4 screws on its front side, after which that cover, with inverter still attached swings open, towards the side with the large breaker (opening from the side with the charge controller). In the photo below, I pointed to two of the screws with a red arrow. Look for two more on the opposite side, hidden by the inverter. These screws should have star washers underneath to bite through the powder-coat and maintain ground continuity while the case is closed. This one pictured is hinged on the left, but yours appears to be hinged on the right. They can be ordered either way. Two metal covers meant to contain the DC wiring seem to be missing from yours, so be on the lookout for those. One would have come with the inverter, the other with the E-panel.

Depending on how many connections are stuffed inside, these narrow-style E-panels can be very tight, so open it slowly while checking for pinched or snagged wires, and note that there are exposed bus-bars with 120VAC on them.

Only one Neutral wire needs to be connected to the inverter's AC terminal block, and it can go to either AC-Neutral-In or AC-Neutral-Out, since these are bonded together inside - Outback's internal transfer switching is single-pole, switching the Hot conductors only. The common neutral wire lands on a bus bar inside the E-panel, which is where both output and input (grid/generator) neutral conductors also connect.

AC and DC breakers can be intermixed on the DIN rails, though you're supposed to place an included plastic separator in between when AC & DC share the same rail. I haven't seen any 65A breakers sold in that size, though - could yours be 63A? That's what Midnite would usually include for charge-controller breakers, one for PV DC-in from panels and one for DC out from the charge controller to the battery bus. These should be wired with #6 AWG stranded. The E-panel also has small bus bars for Battery DC+, PV DC+, and common DC- (the latter attached to an included 500A/50mV shunt for use with a battery monitor) that these charge controller circuits and breakers would connect to, if the panel was wired as recommended.

Normally the AC-out / Bypass breaker assembly comes with a pair of white-colored 50A (AC) breakers under the interlock plate, and a third white, lower-profile 50A breaker will be mounted immediately behind it for the AC-In connection from grid or generator. Maybe that was removed from yours?

The big inverter breaker is likely a 250A, to give some surge headroom for a 24V system. 125A or 175A are best for 48V.

On the other side of the E-panel, directly above the charge controller are three knock-outs for larger panel-mount DC breakers, available in sizes up to 100A. An Outback Flexnet DC battery-monitor module can also mount here, though it's a tight fit inside.

Based on its LCD display showing "PV" and "Bat" rather than "In" and "Out", that charge-controller looks like an MX-60, which is an older variant of the current Flexmax-60.
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Last edited by jnh on Fri Aug 28, 2020 8:37 pm, edited 3 times in total.
jnh
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Posts: 419
Joined: Fri Jun 01, 2007 11:56 am
My RE system: GVFX-3524, FM-80+FM-60, ~4.9kW PV in mixed panels on movable platforms, 415 Ah AGMs @ 24V, 80Ah @ 12V, Hub4, Mate, FNDC, Brultech GEM 32-ch AC datalogger, Midnite E-Panel, homebrew DC-DC crossfeed to 12V system, Honda EU-1000i, AIMS CON120AC1224DC charger
Location: St. Augustine, FL, US

Re: Is this wired correctly? What's going on in the white box?

Post by jnh »

For that well-pump circuit, if your autotransformer is close enough to make this practical, you may want to consider toggling the pump by switching the 120V input to the transformer, rather than its 240V output. This would eliminate the transformer's phantom load whenever you're not pumping water, saving some energy every day. Your pressure switch would need to be beefy enough to handle double the current it is now, though.
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