Battery hookup question

[doox00]

Hey all, I have 9 48v battery packs (with the new jk bms on each one) for my 3 eg4 6000xp inverters. How do I hook these up to the inverters (new system and learning, starting the install process now). Do I run them to bus bars, a negative and positive and from there to each inverter? Is this how you should wire them? Or should I run 3 packs in parallel to each inverter?

Thanks!

 

[Brucey]

I would run each battery to bus bars. Potentially something like three lynx power ins would give you twelve battery connections. then a distributor or power in converted with bolts to hold the megafuses, with the three 6000XPs connected to that. A smart shunt between the negatives of each to track soc.

 

[Brucey]

Make sure the battery cables are the same length, same for inverter cables

 

[Brucey]

Are these 100Ah or 280/300+ Ah batteries? May be able to parallel them into sets of three to reduce number of power in connections

 

[doox00]

Are these 100Ah or 280/300+ Ah batteries? May be able to parallel them into sets of three to reduce number of power in connections

Hey there, 5 packs are 280ah cells and 4 packs are 306 ah cells.

 

[42OhmsPA]

Hey there, 5 packs are 280ah cells and 4 packs are 306 ah cells.

Damn that's a lot of capacity, nice!
I'd use a class T fuse on each pack if you aren't already.

I agree with @Brucey 's advice above, the only thing I'd do differently is build my own bus bars but that isn't for everyone and Victron are a solid choice.

 

[Brucey]

Damn that's a lot of capacity, nice!
I'd use a class T fuse on each pack if you aren't already.

I agree with @Brucey 's advice above, the only thing I'd do differently is build my own bus bars but that isn't for everyone and Victron are a solid choice.

Yes could go with class t power ins, but only two per unit and you'd need five in total...plus say for example you use 250A fuses, two of them with two 250A fuses in each and you are at the 1000A rating of the bus. For 9 big packs another bus design would make sense.

 

[Brucey]

If I was at that kind of capacity and going off the shelf I'd be using one of these:

https://www.stellavolta.com/midnite-solar-mnbcb-2000-200-battery-combiner-box-2000a/

And then use my mnedc250 midnite DC breakers, one per battery. More arc interrupting capability than a class t, and you have individual disconnect capability for maintenance.

 

[42OhmsPA]

Yes could go with class t power ins, but only two per unit and you'd need five in total...plus say for example you use 250A fuses, two of them with two 250A fuses in each and you are at the 1000A rating of the bus. For 9 big packs another bus design would make sense.

I'm working on upgrading mine from this

To something a little different.

@doox00 , might give you some ideas.

 

[doox00]

Yes could go with class t power ins, but only two per unit and you'd need five in total...plus say for example you use 250A fuses, two of them with two 250A fuses in each and you are at the 1000A rating of the bus. For 9 big packs another bus design would make sense.

They are made in DIY cases that have breakers on each pack, do I still need fuses as well?

 

[SparkyJJO]

600A 12 Stud Busbars | Red & Black Kit

Manage high-current electrical connections efficiently with the 600A 12 Stud Busbars in a Red & Black Kit, ensuring organized and reliable power distribution in your electrical setup.

signaturesolar.com

What breakers aee you using on your boxes?

 

[Brucey]

They are made in DIY cases that have breakers on each pack, do I still need fuses as well?

In an ideal scenario there would be multiple redundant systems.

 

[doox00]

600A 12 Stud Busbars | Red & Black Kit

Manage high-current electrical connections efficiently with the 600A 12 Stud Busbars in a Red & Black Kit, ensuring organized and reliable power distribution in your electrical setup.

signaturesolar.com

What breakers aee you using on your boxes?

They are gobel power diy boxes with fuse and breakers in them and YIXIANG diy boxes (not sure if they have a fuse in them or not, waiting for them to arrive, they have breakers though).

 

[robbob2112]

I don't know if I would trust the breaker as more than an on/off switch or not. In general fuses react about 100 times faster than breakers so were it me with that many boxes in parallel I would still do fuses, 1 per - 20% higher than the BMS puts out.

You need fuses on each battery with high AIC breaking ability.

If you choose to do them in groups of three then you need 12 bus bars, 3 shunts, and still 12 fuses. But all of those items can be smaller and the risk of one battery causing the others to dump into it goes way down. I did 12 fuses because I figured 9 in use + 3 spare

According to the manual each 6k uses 140amps so class T for that + 20% = 168amp - you want the JLLN series

https://electricalparts.com/products/littelfuse-jlln175 - $19.95 per fuse + 3 extra = $239.40

And 2awg wire if it will fit the inverters.

Of course the fuse mount blocks there are insane - well they are anywhere - Just realize the class T take a different mount starting after 200amps.
I like these but there are cheaper flavors

Blue Sea Systems 5007100 Ignition Protected Class-T Fuse Block 110-200A

If you decide to go with all batteries connected together then you need 4 bus bars, 1 shunt, and still 9 mounts and the fuses to fill them plus spares....


No matter which way you go, mighty tempting to buy raw bar stock and make your own.

You have a max usage of 350amps so the bus bar needs to be able to carry around 450amps to stay with a 30c rise in temp. We know you won't be maxing that out all the time.

If you make them yourself you would get 110 copper in 1/8" x 2" size. Or use this as a comparison for size, you can't trust anything on amazon that I have found, they all either overstate the capacity or are tricky on how they state the metal used.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

https://www.onlinemetals.com/en/buy/copper-rectangle-bar-101

For choosing sizes look at this table

Electrical: Busbar - Table 3: Quick Busbar Selector

Knowing the ampacity, designers and estimators can get the approximate bus bar size. Ampacity of the bus bar selected must then be verified by checking table 1.

www.copper.org

 

[42OhmsPA]

Check Zoro too.
Free shipping over $50 and frequent coupons if you sign up / buy things.

Zoro Select Copper Rectangle Bar 110-H02 4285_36_0 | Zoro

Order Zoro Select Copper Rectangle Bar 110-H02, 4285_36_0 at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.

www.zoro.com

I'm pretty sure that drop shipped from online metals when I ordered it.

 

[HRTKD]

Before your plan is written in stone, I recommend that you review this thread first.

Calculation of parallel string battery currents

Hi, everybody! I'm a retired EE. I didn't want my EE skills to fade away after retirment, so I exercise them when I can. Whenever I see a non-trivial circuit analysis problem on one of various forums I frequent, I challenge myself to solve it. Recently I watched Will's video about current...

diysolarforum.com

I do like a good solid busbar. In my system, I would rather use a busbar than cable for short runs.

I've been buying mostly aluminum, but lately have purchased copper flat bar, from MidWestSteelSupply.com. In fact, I have a 1"x1/2" bar on order.

 

[robbob2112]

If you decide to drill and tap it with threads it can be a hard material to get a good thread into it. Generally a special tap and a cutting fluid that doesn't corrode the copper is needed. Simpler to just drill the hole and accept that it won't be round and put a bolt through from the other side so you can get compression.

 

[cotter`]

Hmmmm, I have a big piece of copper angle somewhere that I picked up years ago, almost drug it to the scrap yard once... Now where did it get off to?