Wire Trough Wireway for multiple 18kPV Inverters

[WattAboutThat]

I have two (2) questions today:

Q1) I am searching for online links to purchase a wireway wire trough to mount under up to four (4) EG4 18kPV inverters.

a) not sure what terms to use in search
b) have read other forum posts and located
the hoffman trough,
but not sure which to select

I believe I want the following features:

a) 12” x 12” by at least 8’ (feet)
b) a 90 degree corner
c) and another straight piece of 4 to 6’
d) connectors and end caps

I intend to use hydraulic punch
to punch hole patterns for conduit.

——
(this probably should be a different thread)

Q2) If running four EG4 18kPV Inverters,
and for example say Six (6) EG4 battery racks each containing Six (6) EG4 LL (V2) batteries,
for a total of 36 batteries,
what is the required Amperage rating that would be needed on the bus bar connecting all battery racks to all inverters?

And where would I find a bus bar with that capability?

Thank you

 

[WattAboutThat]

my initial thought on bus bar
would be 36 batteries 100A each
3600 Amps

but i feel like that is not correct

 

[DIYrich]

A "trough" is a "wireway" that is factory assembled into a box. You would need the wireway components to get corners, and to join into longer lengths.

Instead of a Punch, you can drill holes.

 

[DIYrich]

(this probably should be a different thread)

Q2) If running four EG4 18kPV Inverters,
and for example say Six (6) EG4 battery racks each containing Six (6) EG4 LL (V2) batteries,
for a total of 36 batteries,
what is the required Amperage rating that would be needed on the bus bar connecting all battery racks to all inverters?

And where would I find a bus bar with that capability?

Thank you

The four parallel inverters require the batteries to also be wired in parallel. The max draw of each inverter from the batteries is around 230 amps. You need a common bus that is capable of handling 4x230 amps, or 920 amps plus 20%, or 1,104 amps. Possibility: Look into the Victron Lynx modules.

I believe each battery rack is rated for 600 amps. I believe 4/0 wire is good for 600 amps up to 9 feet to the busbar. Anything longer, and you need to go even larger, or do not fully populate each rack. Assuming the 4 inverters are maxing out, and all 6 racks working, that would be around 150 amps per rack. If batteries start cutting out (low voltage), the draw on remaining batteries will increase.

I would put a class T fuse and SmartShunt onto each rack before connecting to the bus (use Lynx Power In since you already have the fuse).
I would stagger the batteries and inverter connections. Something like: B-I-B-I-B-B-I-B-I-B. That way you minimize the power going over a portion of the busbar (most current will go from closest battery to closest inverter), but the busbar could handle all the current across the entire width if it had to.

 

[WattAboutThat]

The four parallel inverters require the batteries to also be wired in parallel. The max draw of each inverter from the batteries is around 230 amps. You need a common bus that is capable of handling 4x230 amps, or 920 amps plus 20%, or 1,104 amps. Possibility: Look into the Victron Lynx modules.

I believe each battery rack is rated for 600 amps. I believe 4/0 wire is good for 600 amps up to 9 feet to the busbar. Anything longer, and you need to go even larger, or do not fully populate each rack. Assuming the 4 inverters are maxing out, and all 6 racks working, that would be around 150 amps per rack. If batteries start cutting out (low voltage), the draw on remaining batteries will increase.

I would put a class T fuse and SmartShunt onto each rack before connecting to the bus (use Lynx Power In since you already have the fuse).
I would stagger the batteries and inverter connections. Something like: B-I-B-I-B-B-I-B-I-B. That way you minimize the power going over a portion of the busbar (most current will go from closest battery to closest inverter), but the busbar could handle all the current across the entire width if it had to.

This is great info, and helps me understand how to connect to bus bar.

Thank you

 

[Shimmy]

Completely agree on the fuses for each rack. With four inverters you have a maximum DC bus of 1,200A, so you might want to drop each battery rack down to a 300A fuse.

But, your proposed setup needs to really consider how your battery racks are going to fit into everything physically. You need a single bus that has equal length wires to each cabinet and equal length wires to each inverter... so that bus location is pretty important. You can possibly simplify it at the cost of copper by using a 4" x 1/4" busbar (might be able to get by with something a little smaller) on standoffs for + and - running the entire length, above the wireway. You need to figure out a way to protect them though.

My suggestion would be to draw up all the cables and equipment to scale and see what each cross section of wireway looks like. I think a 12x12 would only work in a perfect scenario.

 

[WattAboutThat]

Completely agree on the fuses for each rack. With four inverters you have a maximum DC bus of 1,200A, so you might want to drop each battery rack down to a 300A fuse.

But, your proposed setup needs to really consider how your battery racks are going to fit into everything physically. You need a single bus that has equal length wires to each cabinet and equal length wires to each inverter... so that bus location is pretty important. You can possibly simplify it at the cost of copper by using a 4" x 1/4" busbar (might be able to get by with something a little smaller) on standoffs for + and - running the entire length, above the wireway. You need to figure out a way to protect them though.

My suggestion would be to draw up all the cables and equipment to scale and see what each cross section of wireway looks like. I think a 12x12 would only work in a perfect scenario.

Thank you for the additional feedback and considerations.

I will weigh all of these factors into the design.

 

[ksmithaz1]

Yes, thats 3600A, except its not its more AMP hours of time. Your bus must handle the current that will be drawn, not what you can feed it. IE the transformer that feeds your house probably can dump 500A, but you are wired for 200A to a 200A breaker in your panel. So you want to be able to hit a demand of 48KW with 48v batteries. You are going to need about 48000W/48V = 1000A + 20% is 1200A on your BUS BARS. You will want to fuse/breaker the feed wires from each battery rack appropriately based on the cable you connect to the bus with. So if you ran 4, 2pos+2neg say 4/0 cables from each rack to the bus bar, you would want a 300 or so amp breaker/fuse inline in each of the positive cables about 600A / rack. That way fuses blow if any load exceeds what your cable can handle. By the same token each of the units should draw/push no more than 300A. 1/0THHN is rated for 150A @ 75C, so two 1/0 from the inverter to the bus bars with 150A breakers inline with the positive cables. There are folks that recommend 125% on the breakers. You can do that but bump to 2/0 wire, noting a 150A breaker should actually run at 5-10% overcurrent for a few minutes, but should not run over 80% for more than a few hours. You should really not ever have anything close to a 200A demand on your panel. I would be surprised if you hit 150A, assuming you have two 4T AC's and your house is all electric. It is rare for everything to be on at the same time, and unheard of for it to all stay running that way for any length of time.

It sounds like you want to fully power a 200A panel. I'm basically doing something similar with a pair of 18K's. I just posted a jpg of my wiring diagram, in a different post. I'm using a 6x6 raceway, and I just ran flex conduit down to the tray. My setup is feeding a transfer switch that is running a 100A panel that is feeding my house. My house is about 1400 sqft, and all electric, I have a single roof mounted 4T A/C, it pulls around 18A, I also have two (2) EV's that I charge, currently using time of use rates. The amount of current down a 4/0 cable seems to be a rather fluid number depending on who you talk to. I've got *one* rack/30 KW of batteries. I've been monitoring my per-leg demand for about the last 4 months with some modbus sensors and an SBC. My mean draw at night is around 12 or so amps (12x240 = 3KW). . . So that 30K of battery should theoretically get me around 10 hours. Figure 6-8 hours for a reality check,we shall see.

The problem is going to be getting enough solar to charge the batteries, and run your loads. As someone in another thread reminded me in Phoenix we get about 6 hours equivalent of direct sunlight at best, so with my 14KW of panels I'm going to net 14KW*6HRS = 84KWH of power/day. Now I'm going to be tapping some of it, directly during the day, and the actual window for the 84KWH is wider than 6 hours, sun comes up where we might see some trickle of juice around 0600, and drops below the horizon around 1900, but that puts me at a minimum of 11 hours of ZERO PV juice. The plan would be to supplement the batteries with off-peak nitetime juice from the grid, until the sun comes up. I may break down and get another rack of 6, but I doubt I would go up to three. Each 5KWH will deliver 50v/100A, so two racks will get you to your 48KW in terms of demand. Adding more is about time. The other problem is the wiring pain goes up exponentially at the number of inverters. You should try and keep your battery wires roughly the same length, so when you have 4 units, you are going to end up looping some of the wires to the inverters closest to the bus. The battery wires and bus bars are going to set you back a big chunk of change.

You might check your electric bill and divide your total kwh by days in your billing cycle. On my worst bill I used about 3500KWH in August (or July, one of them) last year, that's about 116KWH/day... Conclusion: I need more panels before I need more batteries YMMV. It would be pretty slick if I could tap the batteries in my EV's over the long night. This is supposedly coming at some point. I did set up my PV DC/Surge breaker panel to handle 6 strings, I'm only starting with 4, but I want to bring it up to about 20KW with 16 more panels somewhere. Then I might worry about more batteries.

 

[niktak11]

I used hole saws to make the holes in my wireway. I definitely recommend using a knockout punch instead.

 

[ksmithaz1]

I used hole saws to make the holes in my wireway. I definitely recommend using a knockout punch instead.

Anything smallish up to about 3/4 you can get with a step bit. Over that just use a punch. The raceway I have has 1/2+3/4 and 1+1-1/4 knockouts, kind of depends, it's 4x4 not 6x6. I prefer plain boxes, just punch the holes you need of whatever size you need.

 

[Nobodybusiness]

I have two (2) questions today:

Q1) I am searching for online links to purchase a wireway wire trough to mount under up to four (4) EG4 18kPV inverters.

a) not sure what terms to use in search
b) have read other forum posts and located
the hoffman trough,
but not sure which to select

I believe I want the following features:

a) 12” x 12” by at least 8’ (feet)
b) a 90 degree corner
c) and another straight piece of 4 to 6’
d) connectors and end caps

I intend to use hydraulic punch
to punch hole patterns for conduit.

——
(this probably should be a different thread)

Q2) If running four EG4 18kPV Inverters,
and for example say Six (6) EG4 battery racks each containing Six (6) EG4 LL (V2) batteries,
for a total of 36 batteries,
what is the required Amperage rating that would be needed on the bus bar connecting all battery racks to all inverters?

And where would I find a bus bar with that capability?

Thank you

I use the 1000 amp Midnight Solar battery combiner box.

This is the 2000 amp version.
You can double Lug the connections.

Breakers are separate.

Product - MidNite Solar

MidNite Solar Product Page.

www.midnitesolar.com

 

[Nobodybusiness]

I have two (2) questions today:

Q1) I am searching for online links to purchase a wireway wire trough to mount under up to four (4) EG4 18kPV inverters.

a) not sure what terms to use in search
b) have read other forum posts and located
the hoffman trough,
but not sure which to select

I believe I want the following features:

a) 12” x 12” by at least 8’ (feet)
b) a 90 degree corner
c) and another straight piece of 4 to 6’
d) connectors and end caps

I intend to use hydraulic punch
to punch hole patterns for conduit.

——
(this probably should be a different thread)

Q2) If running four EG4 18kPV Inverters,
and for example say Six (6) EG4 battery racks each containing Six (6) EG4 LL (V2) batteries,
for a total of 36 batteries,
what is the required Amperage rating that would be needed on the bus bar connecting all battery racks to all inverters?

And where would I find a bus bar with that capability?

Thank you

I know a lot of folks have advised using Hole saws and punches.

I bought this and it has paid for itself many times over.

For 1/2 inch you can probably just just a Step drill but for 1-4 inches these make perfect cuts with little effort.

https://a.co/d/31GOc5A

 

[niktak11]

Even the cheap knockout punch I have that you use with an impact driver works well. Although I've only gone up to 1 1/4 trade size so far.

 

[Nobodybusiness]

Even the cheap knockout punch I have that you use with an impact driver works well. Although I've only gone up to 1 1/4 trade size so far.

Never tried one of those.

I had to make some 2,3 and 4 inch holes for Nipples between a Transfer switch and Gutter and 2 main panels.

 

[Shimmy]

Somewhat random request for the thread, but does anybody have dimensions to the holes from the wall and left or right reference point? The manual is sadly missing that information. Also... would it be possible to punch a single 2-1/2" (trade size) hole for combined grid and load feed from one of the two 2" (trade size) holes?

@SignatureSolarJames, any chance of getting the manual updated with a better dimensioned diagram and clarity on knock-outs vs punched holes? I am trying to draw up a permit package before purchase and some of the details really matter. If I'm asking for the world... if rear conduit entry is permitted clarification in the manual would be nice.

 

[Nobodybusiness]

Somewhat random request for the thread, but does anybody have dimensions to the holes from the wall and left or right reference point? The manual is sadly missing that information. Also... would it be possible to punch a single 2-1/2" (trade size) hole for combined grid and load feed from one of the two 2" (trade size) holes?

@SignatureSolarJames, any chance of getting the manual updated with a better dimensioned diagram and clarity on knock-outs vs punched holes? I am trying to draw up a permit package before purchase and some of the details really matter. If I'm asking for the world... if rear conduit entry is permitted clarification in the manual would be nice.

I just laid mine on the Gutter after punching out the tabs then traced the hole on the gutter to punch out.

 

[SignatureSolarJames]

Somewhat random request for the thread, but does anybody have dimensions to the holes from the wall and left or right reference point? The manual is sadly missing that information. Also... would it be possible to punch a single 2-1/2" (trade size) hole for combined grid and load feed from one of the two 2" (trade size) holes?

@SignatureSolarJames, any chance of getting the manual updated with a better dimensioned diagram and clarity on knock-outs vs punched holes? I am trying to draw up a permit package before purchase and some of the details really matter. If I'm asking for the world... if rear conduit entry is permitted clarification in the manual would be nice.

We are 2.5 inch hole OD for 2 inch pipe

 

[Shimmy]

We are 2.5 inch hole OD for 2 inch pipe

Thanks, but what I am really looking for is dimensions of where the holes are to help with layout. I have a tight and complicated space I need to work with and the stud bays/bending radiuses are a challenge.

 

[Zwy]

I know a lot of folks have advised using Hole saws and punches.

I bought this and it has paid for itself many times over.

For 1/2 inch you can probably just just a Step drill but for 1-4 inches these make perfect cuts with little effort.

https://a.co/d/31GOc5A

I have this one. https://www.amazon.com/gp/product/B002A94UI2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I punched the Hoffman large cabinet with it, it had the power.

 

[EastTexCowboy]

I know a lot of folks have advised using Hole saws and punches.

I bought this and it has paid for itself many times over.

For 1/2 inch you can probably just just a Step drill but for 1-4 inches these make perfect cuts with little effort.

https://a.co/d/31GOc5A

Nice! I like that it does up to 4" holes, although the largest I've needed so far is 2.5", but it's there if needed. I've been using a hole saw but this is way ahead of that. This goes on my "what I learned today" list. Might be a little hard to justify considering the small scope of work I'm doing on solar but I can see some other uses with some sheet metal projects down the road.