14kwh EVE 280Ah packs & BMS? Looking for confirmation that this is a good purchase.

[Speng]

I'm leaning towards two of these battery packs, with an active balancer of 2A. I have ordered a DEYE SUN 5K-SG04LP1-EU inverter, with a maximum current of 120A.
51.2V, 280Ah 14kwh rack battery pack using EVE cells. JK BMS with 2A Active balancer. Bluetooth functionality (JK-PB2A16S20P).
950 USD EXW.

One unit with wooden packaging weighs 133kg. They quoted me 560 USD DDP shipping per unit (total: 950*2+1050 =2950 USD)
I could ship it through my shipping agent for cheaper at 3.3 USD/KG DDP.
Thats: 877.8 USD International shipping + 50 USD domestic shipping to my agent. (927 USD total shipping cost)
Not sure which of both shipping options I'd pursue. Their shipping is 123 USD more expensive, but it may make things more easy in case anything goes wrong during shipment.

Would you kind folks be willing to inspect their internals?
View attachment 251049
View attachment 251050
View attachment 251051

And these are the included accessories:
View attachment 251053
And here is the datasheet for the JK BMS, and user manual of the battery.
It states that the maximum charging current is 100A and discharging current 200A. Can I effectively use these currents in continuous use?
It would take 5.6 hours to charge both batteries from 0 to 100% with 100A.

The seller says it's better to use 20%-100% capacity for battery life.
So 80% of 560Ah (280*2) is 448 Ah, then it would take 4.48 hours to charge fully.
View attachment 251239This seems to be alright, the 4 hours to charge, if I can effectively charge at such current continuously?
I'm asking because I'll be switching to a dynamic electric tariff, on an hour basis. And theres not often more than 4 hours negative or close to 0 tariffs.

I'm looking to place the order, but would like some opinions on these boxes from experienced users.
Especially regarding the internals, that decent materials were used and that the BMS is a good model (JK-PB2A16S20P). I've searched the forum and seen different opinions regarding these BMSes. If I'm not mistaken this is NOT the inverter model that communicates "closed loop" with the inverter (?). Is that a bad thing? Do I want that? What's the difference between 15P and 20P models? Any other remarks?

Thanks in advance.

 

[cyberfed]

I think they meant to say 80/20 as the battery life, that is, after the initial top balance of your batteries, you discharge them down to about 20% capcity left and then when you charge them you charge them 80% of the max possible charge, assumming LFP 3.65V = 100%. Most people follow this "soft" rule if you are looking to get the max longevity of the batteries (the most cycles). Most folks find themselves usually calling the battery "empty" at 2.8-3.0V and "full" at 3.5V again some may swing to either side on those numbers.

So you are spending around $3K for a do it yourself build of a 16S 48V 280AH pack. Quantity 2.

Are you sure of the seller/company? Meaning are they legit? Selling new grade A batteries that are made in 2024?

I've built essentially the same exact pack well 4 of them to be accurate, with the same BMS, no issues so far in any pack and they all get used daily. Only my I used different batteries.

I would not recommend charging and/or discharging at the maximum continuous values all the time. Can you do it, yeah you can, is it good for the batteries, eh depends on their rating and real world performance. Charging consistently at those rates increasing the probably of batteries swelling. Not to mention everything will be warm, your wires, your fuses, your safety devices, that's a lot of power incoming or outgoing to run consistently daily. Suppose you get a bad battery in a few months, chances are the negative impacts could be more dangerous than if you did a slower charge, again "maybe" I'm not saying any of this is 100% certain.

Would you drive your car at the maximum speed it can go everyday nonstop just because you are able to? If you did, how do you think your car would react in the long term? That's my lame analogy. Again you can build things very safe and be able to move a lot of engery if you want and done right.

What is your solar setup like that you can generate 100A continuously sustained for hours on end? I'm guessing your inverter falls within spec for its max's for your solar setup?

Wires, get GOOD WIRES!!! oversize and get high quality cables you know are made of the right type of stranded copper. If you are making your own, make sure you know how to make a cold weld crimp with the right tools. Add high quality safety devices. Don't use cheap $10 breakers or ANL fuses (not rated for the voltage). T-fuses and CNN/ANN fuses are what you need. I would even add some of those tiny fire surpression bricks or pucks that some vendors who sell rack mounted packs put in them. I actually just learned about these myself and I ordered one which will be "sacrificed" on purpose. If it works as expected, I will put them in my 4 packs and future builds as well. They are designed to minimize the risk of greater fire descruction by taking advantage of the enclosed space (battery compartment).

I have the vendors I trust, as does everyone, and you have to also do a reality check on your skill set and if you have more cash on hand if more bits and parts are needed for whatever reason.

Wishing you the best on your build. Post pics when you are building it!

 

[Speng]

I think they meant to say 80/20 as the battery life

That's what I thought... unfortunate though, as the difference between 22kwh effective useable capacity and 16kwh usable capacity is quite large.

do it yourself build

The company builds it for me. I'm not DIYing it.

Are you sure of the seller/company? Meaning are they legit? Selling new grade A batteries that are made in 2024?

No I'm not. The company is called Shenzhen Xuhongchuang Technology. There's one person who have mentioned them on this forum, and seems to have bought packs from them. See underneath (note that Danke got their PACE BMS, this is the "Old" configuration of their packs, they have since updated and moved onto the hardware that I mention in my thread):

Shenzhen Xuhongchuang Technology

Dora (Shirley) Hu
WhatsApp +8615907674739

280Ah, External Daly active balancer, 200A PACE BMS, DC breaker, wheels and handles front and sides, $950.
If you don’t want the Daly, it is $900.

EDIT: According to vendor, the cells used are 2024 and have been produced last week. I will ask for pictures of QR code in the pack that I'm buying.
EDIT EDIT - I asked for pictures of the battery cells QR code used in my packs before shipment, this was their reply:
"Yes, we can. but then it would need to be re-produced for you. So we need tack 25-30days for new production.

The finished battery can't be photographed with the cell's QR code."
"The QR code of the assembled cell is blocked"
I'm guessing they have some packs ready to ship out, and if I want pictures of QR code of cells used, they have to build some from scratch for me.Is there another way to verify which cells were used in the packs I'd want to buy?

would not recommend charging and/or discharging at the maximum continuous values all the time.

My use case scenario is as follows, during non solar-months, I'd like to maximize profits from the dynamic energy tariffs. When the electricity price is near 0 or negative, the batteries have to charge. This is usually a time slot of 2-4 hours. Then, if there is leftover stored energy and the next day more negative/cheap price is forecasted, and/or there will be solar production, the battery would have to discharge what's left during the most expensive time. Usually in the evening between 6 and 10pm. So as you can see there are usually around two times lots of 2-4 hours in which the battery would have to charge and discharge. If I understand correctly, this would put too much strain on the cells and is not recommended? Because you mention everyday non-stop, well it wouldn't be doing these heavy load charge/discharges all the time. Just when the energy tariff is low/high. See today's price chart as an example: (this varies)

Wires, get GOOD WIRES!!! oversize and get high quality cables you know are made of the right type of stranded copper.

I'm not building my own wires, I'm not looking to build anything myself. For the exact reason you mention, safety. I was hoping the included wires are good? I read about the thread with the guy whose wire connector melted, the click on type. These are the bolt on ones.

I hope they'll be good? A 200A breaker switch will be included. I'll have to look into the other safety devices you mention.

What is your solar setup like that you can generate 100A continuously sustained for hours on end? I'm guessing your inverter falls within spec for its max's for your solar setup?

My solar setup will be 10x 450wp panels (4500wp total) my inverter will be a DEYE SUN 5K-SG04-LP1-EU. But as I mentioned earlier the idea is to control everything with automation based on dynamic tariffs to maximize profitability, but charging at low/negative hours and discharging leftover energy based on predictions when the price is higher. This would be from the grid, and in the months when there is plenty of solar production, the dynamic energy tariff will more often be low or very cheap. Making it not worth to inject leftover energy into the grid. In those months I'd like to limit the inverter to supply solar energy needed for own consumption and filling the battery, but not inject into the grid when the price is low/negative. Though if the grid price is negative (you get paid to use electricity) the battery would charge from the grid, and not by solar. Solar would then be used to provide the home of energy. I hope that makes sense. I'm planning to do the above with Home Assistant and EMHASS.

Your reply is greatly appreciated, what do you think now, once you know all of the above additional information?

EDIT: I'm having everything installed by a professional solar installer/electrician. Though he has never worked with DEYE inverters, nor with lifepo4 batteries. (HVS is the standard here in Belgium).

 

[Brucey]

Especially regarding the internals, that decent materials were used and that the BMS is a good model (JK-PB2A16S20P).

That doesn't looks like a pb2a16s20p?

JK PB2A16S20P JK-PB2A16S-20P - JK BMS

Specification Confirmation Form Customer Name: Customer No.: Customer Part No.: Product Model JK-PB2A16S-20P Version V14.0 Date Accessory List No. Name Model Qty 1 BMS Board JK-PB2A16S-20P 1 2 Display Screen LCD-3.2-RS485-V1.0 1 3...

www.jkbms.com

 

[Speng]

That doesn't looks like a pb2a16s20p?

JK PB2A16S20P JK-PB2A16S-20P - JK BMS

Specification Confirmation Form Customer Name: Customer No.: Customer Part No.: Product Model JK-PB2A16S-20P Version V14.0 Date Accessory List No. Name Model Qty 1 BMS Board JK-PB2A16S-20P 1 2 Display Screen LCD-3.2-RS485-V1.0 1 3...

www.jkbms.com

View attachment 254115

Might have been PACE.

I went with PACE BMS and external DALY active balancers.