question

Hi @Michelle Konzack

That's a very large battery, I'm very jealous you're working on a project of that size. You may have more success on DIY solar forum rather than here.

I don't have experience with that specific BMS, I personally use JK BMS on my several batteries. And my battery shelf is only 2x 16s packs, with each 16s having it's own BMS, a measly 30kwh compared to your 500kwh.

In regards to compatibility with Victron I would suggest using a smart shunt rather than having all those BMS connected to Victron system. It may work however that would be much more complex that just adding one very large smart shunt to monitor the SoC of the battery as a whole rather than each individual BMS reporting SoC. (I think Victron were adding support for multi BMS, but unsure if it's live) Regardless I would just use a smart shunt.

If you want to add the BMS for remote monitoring then you can but smart shunt to me is just easier if you have so many, and unless you're maxing out the batteries then it's just as good as BMS communication in my opinion, and much less of a headache especially with Chinese BMS that may not have supported drivers installed in Venus OS (although odds are there's a community made version on github in most cases)

In regards to paralleling so many cells with BMS. I've seen mixed comments on other sites regarding whether breaching the maximum number of BMS run in parallel stated per manufacturers is safe. Some argue the limit can be breached if further safety precautions are implemented.

ie appropriately sized T-class (fast acting) fuses on each pack as added protection which will blow if inrush current occurs.

However I've not seen a consensus on this.

One thing to consider with so many battery packs is ensuring equal resistances between the packs from the inverters. I imagine a lot of planning has already gone into this/layout given the size of the project but worth flagging.

Another point to flag is I believe the max officially supported system size using Victron inverters currently stands with using 4 units in parallel (each on their own phase). So 12 15kva quattro units, totalling 180kva.

So in theory not hitting the max 1C discharge rate that LiFePO4's can be discharged at. However does mean you'll have 3 hours of run time at peak load, which is insane for 180kva of load.

If the system is single phase the max sizes are smaller again:

Parallel, split- and three phase VE.Bus systems [Victron Energy]

I'm imagine you've already planned this but you'll need a hefty balancer to balance 4x 310ah LiFePO4, the JK BMS i use has a 2a balance built in and that takes a few hours. Unless you've got a absolutely massive power source/PV array ie can stay in absorption for 8hours, you'll need a fair few balances/big ones. Even if each 4p is varying in SoC/balance by say 5%

310* 12.8v = 3.9kwh, 5% = 198wh, balancing at 2amps would take like 8hours.

Definitely worth sinking in the hours on assembly to balance them before building.

I would add that

- you could check also with Seplos, they do have compatible BMS and could chain 16 of them (you can ask them directly through alibaba)

- I would suggest to look after goods through alibaba instead of aliexpress

- yes the DIY solar forum is most probably better for this kind of discussion, I'm afraid writing Seplos has already triggered several red light and you will soon see popping up some "Please refer to the APPROVED battery, else don't expect any help from any Victron resellers"

With this LiFePO4 stuff I get headaches, becsuse everything would be so easy if i can install 72 cellsvSOPzS 4350Ah @48V.

My idea is to convince my customer to accept a long 13m building, which is roughly 2m wide with 4 placements, where 3 are for the batteries and the 4th for the inverters, fuses and such.

The SOPzS are 212mm wide, 576mm deep and 792mm high. Each has filled 240kg. Big doors would make it easy to place this dinos with a forklifttruck or crane into.

The cables (this batteries have 4 poles MINUS and 4 poles PLUS) can be easily joint in the center.

But realy, I do not know, what this Hype with the LiFePO4 Batteries is and where it come from. Recycling if Li batteries is complicate and not the best for the environment while Lead-Acid technology is prooven over more the 100 years and the recycling (at least) in Europe is perfect.

Countries and Mega-Enterprises are fighting for Lithium resources and other metals...

...something to worry about!

P.S.: Not even Solarpanels are environmently friendly produced, even if it could be done. I just bought from Alibaba a pallet of 36 Modules 410Wp for 0,175 US$/Wp plus 100US$ for shipping to Estonia from an European warehouse. This is just 1/4 from what Estonian resellers ask for.

And yes, I would opt for more Solarpanels even if they producebin the summer 10 times as you can use, but in Estonia (59° Latitude) you have in December and January no sun at all. Ibwould need at least a battery of 700kWh @DOD80 net (= 875kWh @24V) in addition to my Windmills. Something impossible. Hence a GenSet which support refurbished Kitchenoil for example...