4x DIY Seplos Mason 280Ah 15kWh - Busbar & fuse question

[netforceatg]

Just want to show my appreciation and say thanks to everyone that shares knowledge and participate on this forum. I’ve been reading here for a while, but this is my first post.

I have ordered 4x Mason 280Ah DIY Kits and will connect them to two Deye SUN-12K-SG04LP3-EU. And I would be grateful if I could get some advice on how wire them up with fuses and breakers safely. I’ve suggested 2 options.

These Mason 280Ah kits come with a built in 400A fuse. And Deye suggest 300A breaker on the towards battery. I was planning to go with option 1:

• 2x Lynx Power modules for input and output between inverters and batteries
• Fuse each battery towards Victron Lynx busbar with 200A Victron Mega Fuse
• Fuse output from Victron Lynx busbar towards Inverter with 300 Victron Mega fuse
• Add a breaker between Inverter and busbar to have a disconnect method for the inverter

But this setup gets quite expensive, multiple lynx modules + fuses, and one thing that concerns me: I have no way of disconnecting the batteries from each other in case of a battery fault. Adding an additional disconnected switch will solve this, but I also do not want to add to many dual purpose parts.

So I’ve come up with Option 2:

• 2x 300A MCCB from Inverters to busbar (Taxi 1Pole TXCM1B)
• 4x 200A MCCB from Batteries to busbar (Taxi 1Pole TXCM1B)
• Custom busbar inside an metal enclosure.
• Cables will be approx. 6ft from inverter to busbar, and 6ft from busbar to batteries

What do you guys think?

 

[houseofancients]

did you see this :

JASSN BUS Bar box 6 studs for split phase

High quality JASSN BUS Bar box 6 studs for split phase from China, China's leading Other parts product market, With strict quality control Other parts factories, Producing high quality JASSN BUS Bar box 6 studs for split phase products.

www.seplos.com

not aware what current pricing is , but look pretty much ideal to me
as for your question , both options would work i think...

 

[netforceatg]

Thanks, I considered the Jassn from Seplos, but it seems that's limited to lower current battery packs(max 100a per battery/stud connections per their homepage)

 

[houseofancients]

Thanks, I considered the Jassn from Seplos, but it seems that's limited to lower current battery packs(max 100a per battery/stud connections per their homepage)

wasn't aware , thanks!

 

[sergea]

Thanks, I considered the Jassn from Seplos, but it seems that's limited to lower current battery packs(max 100a per battery/stud connections per their homepage)

If enough people are interested I can deal with seplos to design a new Jansen for 4 mccb style breaker and 50/70 mm cable. There is an initial design cost to share like what was done for the diy280 box.

 

[sergea]

Thanks, I considered the Jassn from Seplos, but it seems that's limited to lower current battery packs(max 100a per battery/stud connections per their homepage)

You can also use option 3 . Look at this fusr disconnect solution https://voltaconsolar.com/protectio...id-solar-inverter-nh00-250a-fuses-switch.html

 

[RV10flyer]

Option 1 for me. 10 ea diy 280aH batteries, 100A breaker, 2AWG, 125A classT fuse between cells 8 & 9. 1/4" x 2.5" x 84" 1000A bus bars. 250A breakers already in my 12K's. 200A JK BMS, set for 100A max. Typical max 37A per battery.

4 ea 280aH batteries would be absolute minimum for what we have. The more the better.

 

[batterydoctor]

any particular reason you connect the two systems? Why not run independently, if one fails the other keeps going. If they are in parallel this could lead to complications imo

 

[sergea]

any particular reason you connect the two systems? Why not run independently, if one fails the other keeps going. If they are in parallel this could lead to complications imo

There are connected together for resilience and get more power. If one failed or needs maintenance your system stay up.

 

[alexunique]

I came up with exactly the same system design. I am choosing between Lynx Power or custom bus bars. I think circuit breakers for inverters and for batteries are must have, and fuses in Lynx Power are optional.

As for circuit breakers for DC system please ensure they can pass current in both ways, from the screen of TAIXI it looks like it can pass current in only one way (i.e. charge but not discharge, i.e. polarized and check this video). For example on CHYT circuit breaker 2P has +/- on each pole (seen in pictures in description). Anyway you can ask a seller and check on your own before connecting to the system.

 

[629658]

When I did the Calculations manufacturing a custom bus with an enclosure I was within a few dollars of two lynx distributors. I bought the lynx on Amazon for like $150 ea. My second thought was my custom bus would be untested and unrated. The lynx is rated for 1000a and is UL listed as are all my components. So any additional money I spent was peace of mind for me. Can you do it yourself...absolutely.

 

[esurt]

@netforceatg @alexunique Wondering what approach you implemented in the end as I have two Mason 280's on order.

Given the battery fuses should be as close to the battery as possible, I was wondering if make sense to replace the Mason-280 400A with 250A fuses, rather than add additional fuses before (or in) a Lynx Distributor/Power-In? If I was to use a 250A mega-fuse in the battery, why would I need an additional fuse(s) elsewhere?

Your option 2 shows lots of DC breakers, yet these surely these cost more than fuses and take up more space. While not everyone uses them, I know Victron recommend a 200A fuse for each Multiplus II 5kva (I'll have three in a 3-phase setup), but what is the motivation for using DC breakers here and is isolation even required here if i) inverters can be powered-down and ii) batteries and MPPT have isolation (battery switch or fuse disconnector).

 

[netforceatg]

Sorry for my late reply.

Since the Mason280 have a built in 400A fuse(inside) I just went with the battery cable from each Mason to the Lynx Distributur(added 200a fuses per Mason280).

From the Lynx I have a run cable run to each Deye 12kw inverter. These are fused with 250Amp isolator/fuse each so I can disconnect/isolate each inverter from the batteries.

I miss a front panel fuse on each of the batteries and have considered to modify the Mason280. But for now I can live with just pull the quick connector(of the front panel) of Mason280 if something bad were to happen.