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Building my 48(3Px16S)x280Ah EVE Bank in ESS Victron Energy

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Zucca

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Aug 11, 2022
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23
Hello,

first post in this amazing forum.
I am an EE addicted to TEA, but I am trying to get up to speed with batteries and solar system.

I ordered the following for my home in USA:
  1. #48 EVE 280AH, planning to use them as 48V system 3Px16S
  2. #3 Victron Energy MPPT Smartsolar 450-100
  3. #2 Victron Energy Quattro 10KVA 120VAC for Splitphase generation
  4. Other Victron Energy devices... Cerbo and so on
Goal now is now to put everything togheter.... :cool:
I hired a solar company that will take care about the roof PV installation.

The first question I have is where I can buy copper bus bars for the batteries, moreover I can't find any design rules for the ampacity.
As you probably already have guessed, my final battery will be a 48V 840Ah (=280Ahx3) monster, and I would like to get the right busbar for it.
The first obstacle I found in my design is what are the required bus bars dimensions for those battery terminals.

Sure I could use some 4/0 cable, but I think a bus bar is the right trigger to pull in this case.
Yes I am crazy my first system will be at my home and it is not a small one IMHO.

Many thanks in advance for your kind help.
 
First off welcome, it does take a bit of time to come up to speed on the batteries and solar aspect for sure. I came in familiar with electrical very well, but took me some time myself to get comfortable with the modern implementation and all the new solar/battery tech. You'll catch on soon, just keep hanging around here...


On the busbar question you had, did you search for any ampacity charts yet? I usually just look at one of those, and then go on eBay and buy the appropriate size copper bar... I've bought several bus bars from eBay sellers with no problem, good quality.

Like maybe example:
https://www.busbar.com/resources/copper-ampacity/ (or there are many other examples)

And then check out eBay:
www.ebay.com

110 copper bar for sale | eBay

Get the best deals for 110 copper bar at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!
www.ebay.com

Amazon sells the insulator do-dads you can mount the bus bar material to if you need something to hold them and be insulated.


One question I have. I see you're looking at doing 3p16s on your battery. Why not build 3 batteries with 3 BMSs, and have better redundancy? That's what I have gone with on my 48v packs, 16s3p, so you essentially have 3 separate packs in parallel.

In my opinion, the problem with 3p on one BMS is the balancing is too slow to really work well, single BMS has too low of amps rating, requires a huge amp rating of BMS (which costs more and gets hotter), and with a single BMS, it's also hard to diagnose if one cell goes bad and drags down the 2 other cells.

I think it is much easier to spend a bit extra, get 3 BMSs and make them separate packs. Like a good Seplos or JBD BMS or something that are known to work well along side each other in parallel onto the same supply bus.

Doing it this way also makes it easier to do maintenance, as if a pack has a problem, you can have a quick-disconnect on each of the 3 packs (which could be a breaker on each pack), and pull a single pack off the main DC bus easily, service the pack without disrupting service from the rest of the bank to the inverters..

Just my 2 cents is all, take it how you will if you think I may be on to something or not...

I work in datacenters and it's all about redundancy, no single point of failure anywhere in the system is always the logic in the industry.
 
Many many thanks for the reply! Exactly what I needed.

Oh yeah regarding the batteries packs, I was meaning 3 parallel of 16 cells in series, absolutely...16s3p, sorry my mistake.

So now let's go on the bus bar desing:

1) Copper bar with no nickel plated still okay?
2) I need 350A continuous and 1000A peak for about 10sec max.. I would go for 400A ampacity and call it the day.

before I pull the trigger on ebay do you guys knows any company in USA which I can contact directly? Skimming in ebay it is hard to find the lenght and size I need. I would prefer to call somebody and tell then what size I need.
I am sure if I ask some in ebay I will find somebody that do a custom job for me, but maybe you already knows which door I need to knock.

regarding the connections, I need a 250A DC breaker each 16S battery pack and I was plannig an inverted H connection (I hope that's what you call it) to get the two main + and - terminals out.

Can you guys confirm me a 4/0 cable can not handle the point 2) above currents?

Many many thanks in advance
 
Zucca said:
Many many thanks for the reply! Exactly what I needed.

Oh yeah regarding the batteries packs, I was meaning 3 parallel of 16 cells in series, absolutely...16s3p, sorry my mistake.

So now let's go on the bus bar desing:

1) Copper bar with no nickel plated still okay?
2) I need 350A continuous and 1000A peak for about 10sec max.. I would go for 400A ampacity and call it the day.

before I pull the trigger on ebay do you guys knows any company in USA which I can contact directly? Skimming in ebay it is hard to find the lenght and size I need. I would prefer to call somebody and tell then what size I need.
I am sure if I ask some in ebay I will find somebody that do a custom job for me, but maybe you already knows which door I need to knock.

regarding the connections, I need a 250A DC breaker each 16S battery pack and I was plannig an inverted H connection (I hope that's what you call it) to get the two main + and - terminals out.

Can you guys confirm me a 4/0 cable can not handle the point 2) above currents?

Many many thanks in advance
Click to expand...

What are you trying to run that needs 1000a surge (51,200w)?

How many amps are your BMSs rated for?

I am not using plated copper bus bar material on any of my bus bars, mine is holding up fine so far. I am in a dry area though, I don't live by the ocean. If you really want plated or tinned copper, you can look at some of the marine solutions too.

Perhaps a purpose-built marine bus bar?

And the 4/0 cable may or may not be fine, this chart says ampacity is 260a @ 90° C, you might need bigger or run multiple runs in parallel.

Or if it is for two Quattro's, then the current rating you need for the cables wouldn't be 350a but rather half of that (to each one)? If that is the case, then only the bus bar would be seeing the full amperage.

Whatever gauge you go with, just make sure go with a high quality cable, good crimps, and high quality connectors.

The last brand cable I bought which look good quality to me and what I used was from this company,
WindyNation (and comes with tinned ring terminals):

Probably lots of other good brands too...


On my MPP Solar LV6548 system, mine have 6500w inverters each, so I am going to install a 175a breaker onto each battery. I bought a Midnite Solar MNDC breaker box:

www.stellavolta.com

MidNite Solar MNDC175-X2 Mini DC Disconnect 175A Breaker

Shop now for MidNite Solar MNDC175-X2 Mini DC Disconnect 175A Breaker.
www.stellavolta.com www.stellavolta.com

I am adding in a 3rd 175a Midnite Solar DC breaker onto this case (since it only comes with two 175a breakers, and I have three batteries)...

Here's some of Midnite Solar's other DC boxes (they have some with 250a breakers too), they also sell just the breakers by themselves so you can mount in your own box (they do make high quality DC breakers though).

Category Products - MidNite Solar's

MidNite Solar Category Products.
www.midnitesolar.com

Midnite Solar breakers by themselves:

Category Products - MidNite Solar's

MidNite Solar Category Products.
www.midnitesolar.com


Remember breakers are sized to protect the cables.
 
Last edited:
Thank you both again for the help! really appreciate!
Designing with your help makes fun now!

Okay back to the basics, the two VE Quattro are designed to pull max 16KW cont and 40KW peak.
So in a 48V batt I will pull max about 333A cont and 833A peak.
That's why I am leaning to about 400A ampacity for the bus bars: .25 x 1 inch. Done.

I am living also in a dry climate, and if I look at the copper plumbing pipe I see no corrosion on them.
That said I do not want to cut corners and I think just to be safe I will go with a plated bar.

Oh I do not need a disconnect switch, rather a 250A DC (48V min) breaker, like this one
https://www.stellavolta.com/midnite-solar-mnedc250-circuit-breaker-250a-125vdc/
to open in case one battery pack pulls more than 280A. Still have to find the right one, I need something that open fast when >250A...

mmmm wait a minute moment, if I have 3 batteries packs in parallel with each 250A breaker, I should design my bus bar to hold 750A???
Even if I will pull max 333A out cont? To me seems overkill.
 
Zucca said:
Thank you both again for the help! really appreciate!
Designing with your help makes fun now!
Click to expand...

Cool!


Zucca said:
Okay back to the basics, the two VE Quattro are designed to pull max 16KW cont and 40KW peak.
So in a 48V batt I will pull max about 333A cont and 833A peak.
That's why I am leaning to about 400A ampacity for the bus bars: .25 x 1 inch. Done.
Click to expand...

Cool. So each Quattro will draw half of total (one set of cables per Quattro)...


Zucca said:
I am living also in a dry climate, and if I look at the copper plumbing pipe I see no corrosion on them.
That said I do not want to cut corners and I think just to be safe I will go with a plated bar.
Click to expand...

Cool, doesn't hurt to go plated for sure...


Zucca said:
Oh I do not need a disconnect switch, rather a 250A DC (48V min) breaker, like this one
https://www.stellavolta.com/midnite-solar-mnedc250-circuit-breaker-250a-125vdc/
to open in case one battery pack pulls more than 280A. Still have to find the right one, I need something that open fast when >250A...
Click to expand...

So as I kind of indicated previously, my strategy is, my battery BMSs are rated 200a each, and I am going to run 3 battery packs (each with own 200a BMS), so I will cable for 2/0 in my runs (15 ft or less length), and protect with a 175a breaker.

In your case, you will use 4/0, I don't know what your BMSs are capable of supporting, you will protect with 250a breakers each, try to keep the length as short as possible, but just remember again, the breaker is to protect the cables from melting.

The BMS could be a bottleneck if not rated high enough. On mine, I figured 3 batteries, is sufficient to lower the continuous current on each one down fairly low through each BMS so no one BMS is going to run typically higher than half its rated current.

If you are running that much current as you indicate, you might want to make 4 batteries and have 4 BMS? I don't know, just a thought, it does drive the cost up more though.

I also look at it like, if I take one battery out of the circuit for maintenance or failure, can my other 2 batteries handle the load fine for a bit (maybe have to turn a few things off might be fine)...

Zucca said:
mmmm wait a minute moment, if I have 3 batteries packs in parallel with each 250A breaker, I should design my bus bar to hold 750A???
Even if I will pull max 333A out cont? To me seems overkill.
Click to expand...

Yeah, I'd probably just size it for a typical max continuous, that is what makes them get the hottest they will get (sustained current flow), a surge won't alter the average bus bar temperature much, and it is unlikely you'll ever run max on everything at same time anyways. But sizing on cables should match to the breakers (80% rule, and cables sized for length/voltage drop)...

You could / should also consider adding Class-T fuses on each inverter run (sized a bit larger than max inverter draw, but to protect the cable), mounted between the bus bar and each respective inverter (as that section of the circuit, it would take a full 250a x3 before it would be enough to blow the battery breakers).

On my existing 12v RV system I'm living in right now, as I develop my property (before I get my 48v house system together), I have six LFP 4-cell batteries, six 120a continuous 4s BMSs (each battery having its own 150a breaker), then they all join at the bus bar, and goes into one 4/0 feed to the inverter, I have a big Class-T fast-blow 350a fuse to protect that cable run in case the inverter or main cable shorts and tries to draw short circuit current off all six batteries. Does that make sense why I did it that way? I'm going to do the same on my 48v house system, will also put Class-T fuses on each inverter run.
 
Last edited:
BTW, here is a Blue Sea Systems marine bus bar (plated) which are a great brand for certain items (that page has 600a and 1000a bus bar options, I'd recommend the ones with 3/8" bolts and use the larger 3/8" ring terminal connector crimps):


And here's the Class-T fuse holder I bought from Blue Sea Systems (which I like a lot):
www.ebay.com

Blue Sea Systems 5002 Class T Fuse Block 225-400 Amp up to 160v DC for sale online | eBay

Find many great new & used options and get the best deals for Blue Sea Systems 5002 Class T Fuse Block 225-400 Amp up to 160v DC at the best online prices at eBay! Free shipping for many products!
www.ebay.com

For the fuse itself, I used a Littelfuse JLLN 350a fuse (which is a fast-blow fuse)...

Here's the actual fuse I happened to buy for my application (you can find them in other amperage ratings too):
www.ebay.com

Littelfuse JLLN 350 350a 300 Volt Class T Fast Acting Fuse Solar Off Grid for sale online | eBay

Find many great new & used options and get the best deals for Littelfuse JLLN 350 350a 300 Volt Class T Fast Acting Fuse Solar Off Grid at the best online prices at eBay! Free shipping for many products!
www.ebay.com
 
Last edited:
Thanks Samsonite! I appreciate you staying with me in my solar adventure.
Regarding bus bars I will take the https://www.onlinemetals.com and done.

Samsonite801 said:
Here's the actual fuse I happened to buy for my application (you can find them in other amperage ratings too):
Click to expand...

Na, it works for sure but I am looking for a breaker with a switch so I can disconnect the battery if I need to.
On this topic, I see two breakers one on the negative and one on the positive of the battery pack? Why? only one is necessary to me.

Spent the entire night to find the right breaker, problem is the website are not as well designed as mouser or digikey.

here

https://cfgwebprd.carlingtech.com/CI/part-detail

I monkey together this:

Part Number: FS1-B0-12-825-42B-BG


  • F SERIES HYDRAULIC/MAGNETIC CIRCUIT BREAKER
  • MID-TRIP HANDLE ACTUATOR (ONE PER POLE)
  • ONE POLE CIRCUIT BREAKER
  • SERIES TRIP (CURRENT COIL)
  • NO AUXILIARY SWITCH SUPPLIED
  • DELAY CURVE: DC SHORT
  • CURRENT TRIP RATING: 250 AMP
  • TERMINALS: 3/8-16 SCREW (LINE & LOAD), FRONT CONNECTED STYLE
  • MAXIMUM RATING FOR TERMINAL CHOICE: 700 AMPS
  • ACTUATOR COLOR: BLACK; DUAL I-O/ON-OFF LEGEND IN WHITE
  • MOUNTING: #10-32 SCREW CLEARANCE HOLES, BACK MOUNTING TYPE
  • MAXIMUM APP. RATING: VOLTAGE, 125VDC; CURRENT, 700 AMPS
  • UL489 LISTED; CUL CERTIFIED
Click to expand...
 
Zucca said:
Hello,

first post in this amazing forum.
I am an EE addicted to TEA, but I am trying to get up to speed with batteries and solar system.

I ordered the following for my home in USA:
  1. #48 EVE 280AH, planning to use them as 48V system 3Px16S
  2. #3 Victron Energy MPPT Smartsolar 450-100
  3. #2 Victron Energy Quattro 10KVA 120VAC for Splitphase generation
  4. Other Victron Energy devices... Cerbo and so on
Goal now is now to put everything togheter.... :cool:
I hired a solar company that will take care about the roof PV installation.

The first question I have is where I can buy copper bus bars for the batteries, moreover I can't find any design rules for the ampacity.
As you probably already have guessed, my final battery will be a 48V 840Ah (=280Ahx3) monster, and I would like to get the right busbar for it.
The first obstacle I found in my design is what are the required bus bars dimensions for those battery terminals.

Sure I could use some 4/0 cable, but I think a bus bar is the right trigger to pull in this case.
Yes I am crazy my first system will be at my home and it is not a small one IMHO.

Many thanks in advance for your kind help.
Click to expand...
Because you are using Victron equipment's, you should take this inconsideration:

www.victronenergy.com

DC Distribution systems & Fuses - Victron Energy

Victron Energy's DC distribution systems monitor the state of charge of your battery and the state of each fuse. View products now.
www.victronenergy.com www.victronenergy.com

this is the Lynx line of DC distribution, you will not be disappointed and will be cheaper and safer than building your own bus bars.
 
Thanks Sebanavilla!

You are temping me, the Lynx system is very practical and a piece of cake to install.
What is bothering me is the inferior performance compared with a proper designed bus bar system.

160d0606a9324c.png


The batteries are all connected to the left Lynx power in box, and all the rest is on the right (shunt and distributor). This means an asymmetric load or charge for the batteries!

I think that a proper diagonal connection is a better design choice.
See here below for details:

To make things even more complicated, this theory on wiring large systems is a very interesting read!

My system will surely not qualify as large system with two 10KVA inverters and 840Ah 48V battery, but the theory is still valid I think.

Long story short I would like to be as symmetrical as possible.

WAIT a minute moment: I could connect two Lynx distributor left and right on a Lynx power in module where the batteries are connected.... mmmm thinking thinking....
 
Last edited:
Zucca said:
Thanks Sebanavilla!

You are temping me, the Lynx system is very practical and a piece of cake to install.
What is bothering me is the inferior performance compared with a proper designed bus bar system.

160d0606a9324c.png


The batteries are all connected to the left Lynx power in box, and all the rest is on the right (shunt and distributor). This means an asymmetric load or charge for the batteries!

I think that a proper diagonal connection is a better design choice.
See here below for details:

To make things even more complicated, this theory on wiring large systems is a very interesting read!

My system will surely not qualify as large system with two 10KVA inverters and 840Ah 48V battery, but the theory is still valid I think.

Long story short I would like to be as symmetrical as possible.

WAIT a minute moment: I could connect two Lynx distributor left and right on a Lynx power in module where the batteries are connected.... mmmm thinking thinking....
Click to expand...
Exactly my point, you can configure it and add as many distributors or power in as you want, you will still get 1000 AMPs busbar/distribution system.
Regarding the Theory on Wiring Large Systems, "FORGETA 'BOUT IT" ?? your system will never be close to that amount of amps, that is industrial systems.
 
Okay I am sold to the blue color... I could buy everything that is blue now. ;)
 
Last edited:
I know, but in the very screenshot above the Busbars options has still a diagonal connection....

This is a little confusing. The text list has two separate options for diagonal connection (the first) and the Busbars (the last one).
So I would assume, if you go with Busbars you do not need to be diagonal anymore, and the picture seems to go against the list.

Zucca said:
See here below for details:
Click to expand...
In the above video moreover another example of batteries going to a Busbars and then the choice to connect them diagonally.

The only possible reasonable explanation IMHO is that since the connection points to the Lynx system have short distance (there are no long Busbars) it is okay to connect them without a diagonal... because the resistance is still very very low and there is not too much electric imbalance/asymmetric circuit.
 
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