Can I have two busbars since my equipment provides 2 positive & 2 negative terminals?

[AlaskanNoob]

My MPPT has two DC positive terminals, and two DC negative terminals. Same with my Quattro. So could I wire one of the positives to one positive bus bar, and the other two another positive bus bar (mirrored with two negative bus bars) and have one bus bar tied into four batteries, and the other tied into four other batteries?

Or do I need to bridge the two bus bars to make one larger bus bar?

 

[sunshine_eggo]

My MPPT has two DC positive terminals, and two DC negative terminals. Same with my Quattro. So could I wire one of the positives to one positive bus bar, and the other two another positive bus bar (mirrored with two negative bus bars) and have one bus bar tied into four batteries, and the other tied into four other batteries?

Or do I need to bridge the two bus bars to make one larger bus bar?

I vote one big one. If you don't make one big bus bar, you're effectively making the connection AT the Quattro's terminals.

 

[timselectric]

Seconded

 

[AlaskanNoob]

I vote one big one. If you don't make one big bus bar, you're effectively making the connection AT the Quattro's terminals.

I'd rather a big one as well, I just don't know why it would matter since the current gets split in two either way.

And I need 14 terminals on the bus bar and so far haven't found anything that big. I could do two Victron 8 terminal 600A bus bars but I'm not sure how to combine them together into one larger bus bar. So I figured I'd ask if it's even necessary to do so.

 

[sunshine_eggo]

I'd rather a big one as well, I just don't know why it would matter since the current gets split in two either way.

And I need 14 terminals on the bus bar and so far haven't found anything that big. I could do two Victron 8 terminal 600A bus bars but I'm not sure how to combine them together into one larger bus bar. So I figured I'd ask if it's even necessary to do so.

chunk of copper?

Or stray from Victron to a Blue Sea Systems 12 post busbar:

Amazon.com

 

[AlaskanNoob]

chunk of copper?

Or stray from Victron to a Blue Sea Systems 12 post busbar:

Amazon.com

Sure, a chunk of copper. But I need to find one and order it from a link like a civilized person with no tangible skills does. I'm not going to mine it or smelt it or even drill it.

I need 14 terminals, not 12.

 

[AlaskanNoob]

I emailed Blue Seas to see if I can get some specs on this thing. I think it's used to tie t-fuse blocks into the bus bar, but I haven't found anything about the ratings on the thing, ampacity or voltage or even the size of the holes so I can figure out what terminals it will fit on.

SafetyHub Engine Link Bus - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

 

[AlaskanNoob]

Ah, here we go. This should work to tie two bus bars together.

https://www.bluesea.com/products/9160/ML_Series_Link_Bus

 

[629658]

Victron Power In’s. Connect as many as you need. 1000A rated. Only way to fly IMO. Can’t build them much cheaper.

Victron Energy Lynx Power in Battery Connector https://a.co/d/crgbwTV

 

[AlaskanNoob]

Victron Power In’s. Connect as many as you need. 1000A rated. Only way to fly IMO. Can’t build them much cheaper.

Victron Energy Lynx Power in Battery Connector https://a.co/d/crgbwTV

I have two Lynx Distributors but it seems that the MegaFuses aren't going to fit the bill since apparently I need to use t-fuses.

 

[SilverbackMP]

I'd rather a big one as well, I just don't know why it would matter since the current gets split in two either way.

And I need 14 terminals on the bus bar and so far haven't found anything that big. I could do two Victron 8 terminal 600A bus bars but I'm not sure how to combine them together into one larger bus bar. So I figured I'd ask if it's even necessary to do so.

Midnight Solar 2000 Amp battery combiner box (they also have a 1000 amp version). Bit pricey but it’s good quality.

 

[629658]

So I use Power In’s that I modified:

The Distributor was just more money and I didn’t need its features.

I use 300A 48v Mega’s for each individual battery and a class T on the lines feeding the bus. In addition my inverter battery leads are on a breaker and each battery has a breaker. Probably over kill but it works. I have 8 220aH batteries attached to 2 Power Ins using 4/0 tinned pure copper wire. Everything runs cool as a cucumber.

The thing I like about the Power Ins as bus bars they are 1000A rated, they are scalable for expansion, You get both a positive and negative bus, they are protected with covers, and I can’t build a protected bus system with that rating for much less than the $150 I gave for it.

So I don’t have to worry about something falling against my bus and shorting something out. Plus it looks great installed. Win win.

 

[AlaskanNoob]

So I use Power In’s that I modified:

The Distributor was just more money and I didn’t need its features.

I use 300A 48v Mega’s for each individual battery and a class T on the lines feeding the bus. In addition my inverter battery leads are on a breaker and each battery has a breaker. Probably over kill but it works. I have 8 220aH batteries attached to 2 Power Ins using 4/0 tinned pure copper wire. Everything runs cool as a cucumber.

The thing I like about the Power Ins as bus bars they are 1000A rated, they are scalable for expansion, You get both a positive and negative bus, they are protected with covers, and I can’t build a protected bus system with that rating for much less than the $150 I gave for it.

So I don’t have to worry about something falling against my bud and shorting something out. Plus it looks great installed. Win win.

I agree they look great. I had planned on using them for our 8 x 48V/200AH Pylontech US5000 batteries with the megafuses. But we hired a consultant who is now telling us we don't need any fuse/breaker between the battery and the bus, and that we need to use t-fuses between the MPPTs and the bus, and the inverter and the bus. He says the t-fuses won't work with the Lynx. This is the drawing he came up with.

 

[OffGridForGood]

Interesting.
I used 125A T-class between each rack battery and my main Pos Bus, (x5 racks, two 100Ah, three 14.3Ah)
and 300A T-class between each bus (pos and neg) and the inverter-connection cables.
The rack batteries all have breakers, but my concern was a sudden massive short circuit (like a tool or such contacting between the batteries or batt-bus) could unleash massive amperage that the breaker would be fused closed. At the time I set up the ESS I considered ANL fuses rather than the class-T between the batties and bus, as this would have been less costly, in the end I was able to get the T-class so just went this way for the higher interrumpting current capacity these provide.

 

[AlaskanNoob]

Interesting.
I used 125A T-class between each rack battery and my main Pos Bus, (x5 racks, two 100Ah, three 14.3Ah)
and 300A T-class between each bus (pos and neg) and the inverter-connection cables.
The rack batteries all have breakers, but my concern was a sudden massive short circuit (like a tool or such contacting between the batteries or batt-bus) could unleash massive amperage that the breaker would be fused closed. At the time I set up the ESS I considered ANL fuses rather than the class-T between the batties and bus, as this would have been less costly, in the end I was able to get the T-class so just went this way for the higher interrumpting current capacity these provide.

The majority of people I've seen on YouTube and discussing this issue do it as you say. I think I've only seen one or two YTers not protect the battery cables before the bus bar. The Pylontech manual says to protect the cables between the battery and inverter so technically doing it as the consultant drew it would meet that intent. But most do it as you suggest. The consultant said:

As discussed the battery cables connecting to the bus bar have the concerning source of power at the batteries. Thus, unless you can mount the 125A class T fuse you mention right at each battery, there is no point in protecting this wire run. If the class T fuse is at the bus bar, it only protects the bus bar, which does not need protection. The best place for the class T fuses in this installation is as shown - protecting the cables that connect equipment from the high current possible from the batteries. Keeping the battery lead cables short is the most important concern that you have already addressed.

So, as usual, I don't know the best way to proceed. The factory supplied battery cables are 6.5 feet long. Not sure that is "short." If I don't need to protect those cables, best to leave them as is but they'll be 6.5 feet long. If I need protection, I can cut them and put them on breakers or fuses but that means instead of them being in factory state, I will have to cut them and crimp them and possibly introduce issues I had hoped to avoid. Decisions, decisions.

 

[OffGridForGood]

The factory supplied battery cables are 6.5 feet long. Not sure that is "short."

Wow 6.5 feet! In my cabinet the bus bars are 8 inches from the rack batteries, I put a DC rated 125A disconnect, the 125T-Class fuse and short 1AWG cables between each. nothing like 6 feet in my set up, more like 12-inches of total cable from Batt to bus, and as much of it as possible tucked out of the way protected.
If you need 6.5 feet of cable or not would seem to be the question. If you're not comfortable to crimp your own shorter runs, find a local electrican that will crimp for you (you supply the cables and lugs/shrink ready for crimping), or order pre-set lengths online.

 

[timselectric]

The purpose of OCP and short circuit protection, is to protect the conductors.
It can only do this if it's placed at the beginning of the circuit. (At the source)

 

[AlaskanNoob]

Wow 6.5 feet! In my cabinet the bus bars are 8 inches from the rack batteries, I put a DC rated 125A disconnect, the 125T-Class fuse and short 1AWG cables between each. nothing like 6 feet in my set up, more like 12-inches of total cable from Batt to bus, and as much of it as possible tucked out of the way protected.
If you need 6.5 feet of cable or not would seem to be the question. If you're not comfortable to crimp your own shorter runs, find a local electrican that will crimp for you (you supply the cables and lugs/shrink ready for crimping), or order pre-set lengths online.

Pylontech cables come at that length (2000mm). For a set of "networked" batteries in racks, it's about 3 feet from the bottom to the top of the stack. And since they require using their god-awful cables, you can't even parallel them unless you plan to use much less than the rated battery charge/discharge.

Each battery can charge or discharge at 100A continuous, but the cables are only rated to 125A. So putting two batteries in parallel and going full rated charge/discharge is too much for their cables. Horrible god-awful design for a so-called "network battery."

So I'm stuck wiring each battery individually to the bus and that provides physical limitations.

 

[AlaskanNoob]

Here is what Victron offers for implementing these batteries: https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

I'm not sure how you'd have super short cables with a rack of these batteries with their severely limited cable situation. I could shave a couple feet off the 6.5' cable length, but otherwise I'd have to build a shelf or something to elevate the batteries, and put the bus in between the two battery racks to really shorten the cables (or have the inverter and MPPTs super low on the wall). I'm not sure it's worth all that though.

 

[OffGridForGood]

I don't have a picture handy to post, but imagine those rack batteries in a rack cabinet; then on the left side is a main Pos Bus and and on the right a main Neg Bus. The bus bars run the full height of the cabinet. The cable length from each rack battery to each Bus is mere inches, not feet.
The main cables from pos bus to inverter(s) and neg bus to inverter(s) goes first to a 2P main DC disconnect, then to Class T-300A fuses feeding a short bus (one pos one neg) and after the fuses the buses connect the cables to the inverter(s).
That is my set up, I didn't have a consultant and I relied on what I found in (local) code requirements where I live, experience in Industrial construction, and input from the forum members here. I don't say my set up is "best" or even "proper" for your situation, just sharing what I did and the reasoning for it. I feel safe using it, and I have means to disconnect a single rack battery at a time if I need, without shutting down the whole system, and I could/can shut down the entire ESS with a single switch -if ever the need arrises - and so can my key family members.
I am not a big fan of proprietory stuff (connections) that limit choices and often seem to escalate costs in the process. I made and purchased rack batteries with bolt on style terminals, for ease of assembly, maintanence, cable management. Not saying that other cable systems are inferior, just not my style. Maybe those cables can be ordered with a ring terminal end? or modified with crimp on terminals, as an option.