1st off-grid adventure — need charge controller advice

[seneysolar]

Still eyeballing that Outback hard

Get 2

 

[PotusGobbleBottom]

What exactly to you mean?

My experience: I ran 4 solar strings of 12 Ah to a combiner box. Used 8 awg to carry the 48 amps inside to my victron SCC. I tighten and pulled 4x and called it good.... Fast forward 3 months I was installing my 6000xp. I found the 8 awg wire was almost falling out of the pv input. This was probably moreso the heat coming from the SCC more so that the wire heating up but still, it happened. The SCC pv input had slight visible damage from arcing. The daily heating and cooling of the SCC or wire loosened up the connection.

sort of end cap

Those are called ferrules. That are handy with stranded wire into compression fittings. My opinion is that I should be using them, since I have them, But I have not installed them yet.

disconnect breaker off causing an arc flash

Can and does happen. DC arcing potential is much more persistent than AC. It is definitely something to consider when choosing breakers. It absolutely needs to clearly be DC rated. and rated past your PV highest voltage
ARCS are not just "fire" they are plasma. Some very hot stuff.

Per the video, it seems as if the DC arc at 100V has no problem sustaining an acr at 3/4 of an inch. Guess what? Most switches dont have 3/4 of an inch of separation. They have specific designs to quench the arc in a smaller space at a specific voltage.

when/how

If you pulled 200 A DC thru a 100A AC rated switch, Bad things could happen. Im not sure of the specific thresholds for angry breakers or switches. Just make sure its properly rated.

small box that I can just pass thru to have fuses and a disconnect

Thats what a combiner box does.

how "would an arc flash when I turn it off" happen

Interrupting the travel of electrons of any nature has arc potential. Some tiny, some huge and everything in between.

2P

You would be fine for 2P actually. Its just that 3P needs a fuse. Those Y connectors are handy for 2P but I wouldn't use them everywhere. I guess Im not sure why I feel so strongly against them. Perhaps I forgot something!

 

[AC/DC]

You would be fine for 2P actually. Its just that 3P needs a fuse. Those Y connectors are handy for 2P but I wouldn't use them everywhere. I guess Im not sure why I feel so strongly against them. Perhaps I forgot something!

Great info, thanks. To recap, are you saying that for 2P which will put me at 22A I'm good to just Y combine at the panels and send it to my "shack" (what's the term used here, where your equipment is?), which is my garage, and I don't need a fuse until I go 3P or above?

Those are called ferrules. That are handy with stranded wire into compression fittings. My opinion is that I should be using them, since I have them, But I have not installed them yet.

I'll research. Is standard solar-rated wire stranded or not? Def interested in these, looked really nice in the vid.

Thats what a combiner box does.

Right, but I'm trying not to use a combiner box since I'm gonna use Y connectors to combine the two strings at the panel end. I still want to get a disconnect, ideally in a little box, and if going thru all that trouble, if one were to come with a fuse, why not. So something just with disconnect and, optionally, fuses but no combining, does something like that exist or does it need to be DIY? Fuse optional but 100% want a disconnect.

Mounting Equipment to .. what?
I'm not an electrician and have never done anything to this level with electrical stuff. I have an engineering mindset and am not intimidated by the project, I just get stuck on some of the physical things. Like what do I mount all of these to, the MPPT, the disconnects, stuff from my battery? I see a lot of people using planks of wood? I don't have a truck (just a Model Y SUV), I can't carry very large board. Where do I learn about the physical part of building this stuff out somewhat neatly, and functionally sound?

Here's what I have RIGHT NOW which will be going in the garage:

• a garage with some space; house panel is near location I plan to start this project, let's call it the "you may end up sleeping on the couch, or worse" project
• two (2) EcoWorthy 12.8V 150Ah batteries, connected in series for 25.6V 150Ah
• a 3000W 24V inverter
• a bunch of AC chargers that do not need to live in the garage
• a DEWALT 3-Tier Steel Storage Unit (50" x 48" x 18") — Will showcased this unit in at least one video

So, already, I'm rather concerned that the Dewalt is made out of steel and I have .. electrical components with exposed terminals. The batteries are fine, they are blocky and heavy and terminals are toward the top. Inverter is fine too, posts are covered, but.. it will be resting on the steel shelving.. is this an issue?

Stuff to come and for me to figure out:

• battery disconnect — have the switch, haven't yet installed. it is the type of switch that can mount in a hole
• battery monitor — already have it, it has a shunt, ideally this is not hanging in the air? what/how do I mount it..
• CC, either Victron 250/100 or Outback or something. with the Victron at least, looking at it, I'd be VERY uncomfortable having it on the steel shelf, as the terminals are at the bottom and according to what @ScrotusGobbleBottom said about 8 awg wires almost falling out, BIG BOOM could happen.
• PV disconnect box/mechanism, will need to mount to something, otherwise lay on the shelf? hopefully I can buy a kit which comes as an insulated plastic box, so while not pretty, laying on the steel shelf would at least be an option, at least to start
• stuff that I'm missing

So I want to at least have a gameplan in my mind as to how to set this up. Because I haven't done this kind of stuff before, it's a big stumbling block, I need to figure out what I need to source and how it will go together, if not exactly at least the overall idea.

 

[Zwy]

I would just use the EG4 MPPT, all panels in series, 10AWG wire and watch the watts roll in. I run a pair with 8 530W panels on each one.

This would easily handle your 6 panels. Cost is $399 plus shipping.

 

[PotusGobbleBottom]

don't need a fuse until I go 3P or above

Correct Think of it this way. A solar panel can take a short circuit of its own power all day and not complain. In 2P it would take double its own, and in 3P it could take triple. Thats my understanding. Solar panels get angry with triple their rated short circuit current.

Is standard solar-rated wire stranded or not

PV wire is always stranded "out in the wind" Any time a conductor has high frequency of moving, you use stranded.

So something just with disconnect and, optionally, fuses but no combining, does something like that exist or does it need to be DIY

yes, a properly rated DC circuit breaker would be your "fuse" and disconnect. You can mount it to a din rail on the wall all by itself. or in a din box

https://www.amazon.com/Circuit-Distribution-Protection-Waterproof-Way/dp/B09XJZR51G?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=AOAWBY89MKXUL

physical part of building this stuff out somewhat neatly, and functionally sound?

This very much depends on what your are mounting too and the weights of everything. I mounted my 6000xp on my basement wall, all other things are mounted in a wood cabinet with some of my batteries. I have positive and negative bus separated by a full wood divider in the cabinet with my shunt. This is where the 6000xps inclusion of breakers really shines. No extra wire, no extra mounts.

according to what @ScrotusGobbleBottom said about 8 awg wires almost falling out, BIG BOOM could happen

and remember, the pv line CANT be fused to trip on overcurrent because your always aiming for max. Its the wrong place for a fuse.
You could put a DC AFCI on there to detect arcs tho.

 

[PotusGobbleBottom]

will need to mount to something, otherwise lay on the shelf

Just cut some cement board to place on top of the shelf. Bonus fire resistance.
I recently learned that concrete does conduct slightly but I think you would be fine at these voltages.

https://www.lowes.com/pd/DUROCK-Brand-0-25-in-x-36-in-x-60-in-Cement-Backer-Board/1000383885

 

[AC/DC]

I would just use the EG4 MPPT, all panels in series, 10AWG wire and watch the watts roll in. I run a pair with 8 530W panels on each one.

This would easily handle your 6 panels. Cost is $399 plus shipping.

Oh man, you're tempting me! I love me some simplicity.. only issue is that it's 48V only and I'm on 24V, ugh..

Just cut some cement board to place on top of the shelf. Bonus fire resistance.
I recently learned that concrete does conduct slightly but I think you would be fine at these voltages.

https://www.lowes.com/pd/DUROCK-Brand-0-25-in-x-36-in-x-60-in-Cement-Backer-Board/1000383885

Would this to drill into and securely mount, or just as an insulation between the rack and components, which will mostly lay there?

 

[PotusGobbleBottom]

Would this to drill into and securely mount, or just as an insulation between the rack and components, which will mostly lay there?

I would consider it able to keep things where you want with < 10lbs weight and horizontal.

Will had a video recomending wall mounting concrete board but I am thinking he drilled into a stud behind it for the heavy stuff.
The concrete board I have used I wouldnt hang something over 20 lbs on it, not even with robust dry wall anchors.

 

[Hedges]

Because my array can technically put out 82A at 24V charge voltage (~29V), there's not a ton of choice.. unless I go to 48V and cut those charge amps in half,

If you parallel strings of different orientation, you will get lower peak current, more hours of operation. That's more kWh from same charge controller, and fewer hours of relying on battery so more power available at night.

If you do over-panel and have some clipping, that's only during best days and hours. When you can probably afford to let some kWh escape. Panels are cheap (mounting no so much), so overpaneling is a way to get more power during off season, and more power per day.

 

[Zwy]

Oh man, you're tempting me! I love me some simplicity.. only issue is that it's 48V only and I'm on 24V, ugh..

I didn't catch the 24V system. If you're thinking 48V down the line, then I would move to 48V now and use the 3000W 24V inverter for something else like a portable system.

So much capability with 48V.

 

[AC/DC]

I didn't catch the 24V system. If you're thinking 48V down the line, then I would move to 48V now and use the 3000W 24V inverter for something else like a portable system.

So much capability with 48V.

Yea I'm looking hard at 48V it's just a safety thing for now. If/when I build a proper, cased battery I'll feel safer, but right now I'm making my own out of large individual 12V bats and I have 10 year olds around. Also want to keep it low voltage on the battery side (where I expect to work on most on an ongoing basis, whereas the PV stuff is mostly one time setup then just disconnect/move around) for the time being while I develop good habits.

Now, it would also require a lot of $ upfront to get to use these panels that are just sitting there in my backyard (not the least of which is an inverter, which I'd want to go with split-phase right away to be able to provide 240V so I can L2 charge the EVs). Theoretically, could I hook up the inverter directly to the CC and use power w/o a battery during the day? Cuz I don't have a 48V battery right now (and would wait for another sale from EcoWorthy to pick up 2 more 12.8V 150Ah units).

What affordable split-phase 48V inverters shall I be looking at? Of course I'd love a 6000XP, and if I didn't have to buy two to get 240V, I'd eat the $1.5k cost right now. Is WZRELB any good? What else should I look at? Is there an all-in-one like the 6000XP that has a CC but also does 240V?

 

[Brucey]

Yea I'm looking hard at 48V it's just a safety thing for now. If/when I build a proper, cased battery I'll feel safer, but right now I'm making my own out of large individual 12V bats and I have 10 year olds around. Also want to keep it low voltage on the battery side (where I expect to work on most on an ongoing basis, whereas the PV stuff is mostly one time setup then just disconnect/move around) for the time being while I develop good habits.

Now, it would also require a lot of $ upfront to get to use these panels that are just sitting there in my backyard (not the least of which is an inverter, which I'd want to go with split-phase right away to be able to provide 240V so I can L2 charge the EVs). Theoretically, could I hook up the inverter directly to the CC and use power w/o a battery during the day? Cuz I don't have a 48V battery right now (and would wait for another sale from EcoWorthy to pick up 2 more 12.8V 150Ah units).

What affordable split-phase 48V inverters shall I be looking at? Of course I'd love a 6000XP, and if I didn't have to buy two to get 240V, I'd eat the $1.5k cost right now. Is WZRELB any good? What else should I look at? Is there an all-in-one like the 6000XP that has a CC but also does 240V?

6000XP is split phase with single unit

EG4 6000XP Off-Grid Inverter | 8000W PV Input | 6000W Output | 480V VOC Input | 48V 120/240V Split Phase | All-In-One Solar Inverter

The EG4 6000XP is a cutting-edge 48V split-phase, off-grid inverter and charger, designed to revolutionize your energy needs. With an impressive 8kW of PV input capacity and an efficient 6kW continuous power output, it also serves as a battery 140A charger. What sets it apart is its scalability...

signaturesolar.com

 

[AC/DC]

6000XP is split phase with single unit

So weird, I could have sworn that I saw that you needed two for 240 split. Thanks! Now there's some serious internal debating to be had.. Just a shame those panels are just sitting outside doing nothing while I contemplate a 48V system.

 

[Zwy]

Yea I'm looking hard at 48V it's just a safety thing for now. If/when I build a proper, cased battery I'll feel safer, but right now I'm making my own out of large individual 12V bats and I have 10 year olds around. Also want to keep it low voltage on the battery side (where I expect to work on most on an ongoing basis, whereas the PV stuff is mostly one time setup then just disconnect/move around) for the time being while I develop good habits.

Now, it would also require a lot of $ upfront to get to use these panels that are just sitting there in my backyard (not the least of which is an inverter, which I'd want to go with split-phase right away to be able to provide 240V so I can L2 charge the EVs). Theoretically, could I hook up the inverter directly to the CC and use power w/o a battery during the day? Cuz I don't have a 48V battery right now (and would wait for another sale from EcoWorthy to pick up 2 more 12.8V 150Ah units).

What affordable split-phase 48V inverters shall I be looking at? Of course I'd love a 6000XP, and if I didn't have to buy two to get 240V, I'd eat the $1.5k cost right now. Is WZRELB any good? What else should I look at? Is there an all-in-one like the 6000XP that has a CC but also does 240V?

The 10 Kw SRNE does split phase 240V. About the same price as the 6000XP, but it much larger and some members run the whole house off it.

The latest from Watts247, the NHX hybrid series might be a good choice. Some members have been testing this unit, it may have the glitches fixed from the previous Megarevo built inverters. The NHX is different hardware/software and interface.

 

[AC/DC]

yes, a properly rated DC circuit breaker would be your "fuse" and disconnect. You can mount it to a din rail on the wall all by itself. or in a din box

https://www.amazon.com/Circuit-Distribution-Protection-Waterproof-Way/dp/B09XJZR51G?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=AOAWBY89MKXUL

What breaker do you recommend? I'm having a tough time finding one, HD/Lowes don't seem to have DC stuff and on Amazon I'm not finding UL-listed ones, just some that say CE. Hard to discern quality, money is not a huge factor at this stage, it's for safety so I'd rather get a good one that people here recommend.

While at it, what Class-T fuse do y'all recommend? Right now I'd probably be good with 200-300A (my bat is 150Ah but wouldn't mind having the ability to discharge above 1C for special surge situations).

Can and does happen. DC arcing potential is much more persistent than AC. It is definitely something to consider when choosing breakers. It absolutely needs to clearly be DC rated. and rated past your PV highest voltage
ARCS are not just "fire" they are plasma. Some very hot stuff.

Per the video, it seems as if the DC arc at 100V has no problem sustaining an acr at 3/4 of an inch. Guess what? Most switches dont have 3/4 of an inch of separation. They have specific designs to quench the arc in a smaller space at a specific voltage.

To be perfectly clear in my mind, this would only happen when positive is close to negative, correct? Such as when the wires in a circuit breaker, or the CC, are close, but not when I'm plugging/unplugging an MC4 that is energized anywhere in the system, as that would be on the same polarity.

 

[Brucey]

What breaker do you recommend? I'm having a tough time finding one, HD/Lowes don't seem to have DC stuff and on Amazon I'm not finding UL-listed ones, just some that say CE. Hard to discern quality, money is not a huge factor at this stage, it's for safety so I'd rather get a good one that people here recommend.

While at it, what Class-T fuse do y'all recommend? Right now I'd probably be good with 200-300A (my bat is 150Ah but wouldn't mind having the ability to discharge above 1C for special surge situations).


To be perfectly clear in my mind, this would only happen when positive is close to negative, correct? Such as when the wires in a circuit breaker, or the CC, are close, but not when I'm plugging/unplugging an MC4 that is energized anywhere in the system, as that would be on the same polarity.

If the solar circuit isn't interrupted you could get an arc when you disconnect the mc4 connector. So you would close the breaker/DC disconnect prior to doing work.

 

[seneysolar]

home depot wont be a good source for anything rated DC.

 

[PotusGobbleBottom]

To be perfectly clear in my mind, this would only happen when positive is close to negative, correct?

Not only then, also when disconnecting under load.

 

[PotusGobbleBottom]

What breaker do you recommend?

Hoping someone else can help here. Mine came with my combiner box.

but not when I'm plugging/unplugging an MC4 that is energized anywhere in the system, as that would be on the same polarity.

It absolutely can when you disconnect a circuit under load aka charging you batteries.
MC4s would be energized by the sun OR panels wired in parallel. the solar charge controller would be the load.

If you have a pv disconnect switched off, then there is no load on the panels, and no arc will happen with a same polarity mc4

 

[Brucey]

What breaker do you recommend? I'm having a tough time finding one, HD/Lowes don't seem to have DC stuff and on Amazon I'm not finding UL-listed ones, just some that say CE. Hard to discern quality, money is not a huge factor at this stage, it's for safety so I'd rather get a good one that people here recommend.

While at it, what Class-T fuse do y'all recommend? Right now I'd probably be good with 200-300A (my bat is 150Ah but wouldn't mind having the ability to discharge above 1C for special surge situations).


To be perfectly clear in my mind, this would only happen when positive is close to negative, correct? Such as when the wires in a circuit breaker, or the CC, are close, but not when I'm plugging/unplugging an MC4 that is energized anywhere in the system, as that would be on the same polarity.

Stellavolta.com have many of the Midnite breakers and you can use Amazon pay to checkout.