64 eve lLF280k version3 cells in 8P8S configuation 24-volt build December 28th, 2023

[michael d]

I ordered 64 cells lf280k from a previous supplier today December 28th, 2023 to assemble a 8P8S 24-volt battery for my off-grid farm...

64 of the LF280k version 3 cells, bolts, busbars, insulator sheets included, and strapping tape. for $6615.03 shipped to me in the USA from the China warehouse that is located in the USA ....

Shelly Yang helped me.
this is the 3rd batch I ordered so expect all to go well...
after a lot of texts etc
and a confirmation process through the credit card and Alibaba trade assurance problems...
the payment finally went through..... woo hoo

8p = 280 x8 = 2240 amp
8s = 3.2x8 = 25.6 volt
these are nominal figures

I connect the 8P 1st...
then connect each row to the next in series

I already have two of the 2P8S and two of 4P8S assembled and running for 1- 2 years....
more later.

I believe the new batch of cells is being shipped out of the warehouse in Texas so should be at my door in a few days...?

we had about 8 inches of new snow Christmas day so been scooping a lot of snow in order to more easily feed the critters at my off-grid farm....fired up the Case diesel uni-loader yesterday December 27th, 2023 >>> to clear the road for the semi-truck delivery coming soon
hope you all had a wonderful holiday and some rest and relaxation with your families...???

 

[740GLE]

What BMS are you going with?

 

[michael d]

What BMS are you going with?

Electrodacus SBMS0 will control the charging via the new Electrodacus SBMS0 using the new Electrodacus DSSR50 and mounting them on a din rail.

each Electrodacus DSSR50 will control all 60 PV solar panels with 4 of the 290-watt solar panels per DSSR50 in this build.... the DSSR50 will give all the charge available and is not an MPPT.... it will need 15 of the new DSSR50s to control the 17,400 watts.
I think the Electrodacus DSSR50 cost about 50 dollars each... (not sure about that price at the moment)

the 290-watt panels are parallel at the array in sets of two... they are 72-cell PV panels.... I bought 60 of those solar panels for $3100 including delivery. they are used Trina solar PV panels...
290 x 60 = 17,400 watt solar PV array

the Electrodaus can control up to 8 for the 24-volt configuration. 8P8S
each set of 8 cells in parallel acts as a single cell.... so one small control sense wire to each set of 8 cells in parallel...
8 small sense wires plus a couple of other small sense control wires to the battery bank will do the passive cell balancing while charging from solar PV panels...

3.2V x 280Ah x 64 cells = 57,344 Wh potential capacity
how many expensive pre-built batteries at $1250 each would it take to get 57,344 Wh???? you do this math and find DIY is a lot less dinero, but DIY takes more time to do of course!!!!!

280A x 8 = 2,240 amps when connected in series

I plan to top balance the cells with my Riden 6018 and 6024 chargers.

everything is done off-grid and nothing is connected to the grid...

The Riden chargers are powered via inverters connected to other 24-volt LifePO4 battery builds...
the top balancing will be the tedious slow part....(definitely)

more later ,?

 

[Steve_S]

For clarity as I am curious...
Is your intention is to build a single battery with 8 cells in parallel in 8S form for 24V OR 8 Battery packs in standard 8S format to put into one paralleled bank ?

 

[740GLE]

The way I read it it’s 8 cells in parallel.

I’d love to see the cell bus bars that can support 2,240a let alone the interconnecting cables ?

 

[michael d]

on my 4p 8s it is 32 cell making a battery of 24 volts
this one will be 8p8s making a 24 volt battery
the larger thick bus bar on each end of the 8p8s is about .25 inch thick and has 4 thick copper wires connecting to it.
i do not have the dimension in the back of my head so will have to go measure or look in the older records of that build..

i will not be pulling 2,240 amps ever at 24-volts but the battery build will have that amount of potential amperage and the potential capacity of 57,734 Wh...

each set of 8 cells connected in parallel acts as a single cell....
each small sense wire will balance those 8 cells tat act as a single cell in parallel....
the Electrodacus has 8 of those small sense wires to control the balancing.

the series cells were connected with short copper cables I think I used 2/0 copper for these inter connections ((( but again I would have to go find the exact cable size I used on the 4p8s build)))

I bought some larger copper bus bars to make a larger battery I think they are 3/8 inch by 2 inch x 12 inches or so.... (( I will measure them later)))

 

[michael d]

The way I read it it’s 8 cells in parallel.

I’d love to see the cell bus bars that can support 2,240a let alone the interconnecting cables ?

I am trying to write this so you understand >>>> it is 8 cells connected in parallel first!!!! which acts as a single large cell and will be balanced by one of the small sense wires from the Electrodacus SBMS0...

then each of those large paralleled cells will be interconnected to the next set of 8 parallel cells in series, then the next in series, then the next in series etc... with the final series connections yielding 25.6 volts nominal...

54 series cable interconnections

then 16 more connections via copper cable to the busbar on each end (8 on each end)

yes, it is confusing but it has worked well in the 2P8S and 4P8S builds.....

I will increase the cabling sizes and the busbar sizes....
the factory bus bars work well for the parallel connections...
the series interconnections I use tinned copper lugs with short copper cables that I make up with a hydraulic crimper and use adhesive heat shrink to cover these lugs....

I may use 4/0 copper for the interconnections as I already have that cable and all the 4/0 lugs to fit....
it will take about 6 hours to make up those cables (approximately) (((((54 plus 16 is 70 cables to hydraulically crimp etc...)))))

64 cells at 5.4 kg weighs a lot >>>> 64x5.4 = 345.6 kg or (( for me 345 x 2.2 = 760.32 pounds)) Approximately not including the bus bars or cabling !!!!!!

the cells are connected in parallel 1st to make the 8P combined cell using 280Ah Eve Cells in this build..
64 cells will ultimately be an 8x8 block to make the 64 cell battery....

multiple inverters can be hooked to the same bus bars also,,,, and not the high overpriced Victron super dependable everyone raves about either....

I am still learning through many years of reading...//// studying.....DIY for 50 plus years farm boy for 60 plus years college 10 plus years.... still learning every day so suggestions are always read and studied before implementing....

but it still seems when one gets to adding up all the required charge controllers, pv combiner boxes, etc to control 18,000 watts of PV solar panels this still is doable a few parts at a time....

no combiner box is needed when assembling the 2 panels at a time in parallel at the solar PV array....

the LiFePO4 battery back-up is the most expensive part of my systems.... off-grid
I am not connected to the grid in any way on this....

 

[michael d]

For clarity as I am curious...
Is your intention is to build a single battery with 8 cells in parallel in 8S form for 24V OR 8 Battery packs in standard 8S format to put into one paralleled bank ?

8x8 64 cells
will make the 25.6 volt nominal battery

 

[Steve_S]

I really really hope you bought properly Matched & Batched cells with full reports showing the IR at the the test points.

You do realize that if you built 8x 24V/280AH packs with 200A capacity, that gives you 1600A deliverable to loads shared & divided between them. That this also provides fault tolerance & fail over should any pack "stop" for any reason... Just tossing it out there... I have not seen anyone here build a single pack beyond 2P#S. Most especially because these are ESS cells and not genuine Verified EV Grade cells, even if a vendors says they are...

 

[Partimewages]

Just my opinion but this type of build will be a service nightmare and you will be down. It's not what I would want.

 

[Steve_S]

I've been at this a while now... I wouldn't even dream of building that... And I do have access to proper A-Grade Matched & Batched cells.

 

[michael d]

I really really hope you bought properly Matched & Batched cells with full reports showing the IR at the the test points.

You do realize that if you built 8x 24V/280AH packs with 200A capacity, that gives you 1600A deliverable to loads shared & divided between them. That this also provides fault tolerance & fail over should any pack "stop" for any reason... Just tossing it out there... I have not seen anyone here build a single pack beyond 2P#S. Most especially because these are ESS cells and not genuine Verified EV Grade cells, even if a vendors says they are...

I have on two occasions built 4p8s and I believe I have previously mentioned them in this forum...
I know you have many more years of off-grid building and I appreciate the ideas /suggestions....
the cells are brand new grade A cells version 3 and this is the 3rd batch from this same supplier....
I also know or read that all vendors make exaggerated claims of quality etc....
my redundancy is in the other batteries already in use 2p8S two of those and 4p8s two of those;
this new build is working toward 8p8s ..... at 25.6 volts nominal...
when I have more time I will try to send more pictures diagrams and details....
again I do appreciate suggestions/ ideas
I find it difficult at times to get the electrical jargon on paper typing for others to follow...
when I go to Bolivia South America I often use pictures and diagrams as Spanish and the many dialects used there is always a challenge..
English is my 1st language and Spanish I have been learning for over 45 years and still have no claim to fluency in Spanish...

 

[michael d]

Just my opinion but this type of build will be a service nightmare and you will be down. It's not what I would want.

I could downsize it to a 4p8s configuration and make two more of those.....
I have no downtime with the other two 8P4S builds so far...
but that requires an additional Electrodacus SBMS0 one for each 32 cells if I downsize....to the 8P4S configuration
I think the Electrodacus SBMS0 costs about 160 dollars each currently....

 

[Steve_S]

I have on two occasions built 4p8s and I believe I have previously mentioned them in this forum...
I know you have many more years of off-grid building and I appreciate the ideas /suggestions....
the cells are brand new grade A cells version 3 and this is the 3rd batch from this same supplier....
I also know or read that all vendors make exaggerated claims of quality etc....
my redundancy is in the other batteries already in use 2p84 two those and 4p8s two of those;
this new build is working toward 8p8s ..... at 25.6 volts nominal...
when I have more time I will try to send more pictures diagrams and details....
again I do appreciate suggestion/ ideas
I find it difficult at times to get the electrical jargon on paper typing for others to follow...
when I go to Bolivia South America I often use pictures and diagrams as Spanish and the many dialects used there is always a challenge..
English is my 1st language and Spanish I have been learning for over 45 years and still have no claim to fluency in Spanish...

I speak 5 languages and totally get confusion... Then when you get to tech, Holy Macaroni things can go sideways in a poof.

 

[michael d]

I was considering putting 2 batteries (((24-volt in series with another 24-volt )))in series to get 48-volt but not sure about that at the moment. I have some 4inchx12inch by 1/4 inch thick copper bus bar tinned for that idea...... still analyzing that idea..
but I still working toward the 64 cell 8x8 25.6volt assembly at this time....

 

[SparkyJJO]

If you do 48V I would suggest purpose building one using a 16S BMS. Just tends to work better long term.

 

[michael d]

cost compare some things:

5.12 kWh EG4 for $1259 ; is prebuilt 48v 100ah; includes the built in BMS in server rack mount type that is the EG4 sale price for Christmas 2023...

vs 57,734 Wh or 57.734 kHh DIY for $6615.03 plus a bunch of cables and one Electrodacus SBMS0 etc and a huge time commitment for DIY

57.734 / 5.12 = 11.276 of the prebuilt server rack batteries and at $1259 on sale price..... that same ess would be >>>>
$1259 x 11.276 = 14,196.84 dollars

so the DIY I can utilize my time for $7000 plus savings and build the ESS on my time....
as the 64 lf280k version 3 cells and some accessories cost me 6615.03 dollars so far...
the Electrodacus SBMS0 was about 150 dollars delivered to me in the USA... (approximately)

14196 minus (6615 (+ 150 for the Electrodacus SBMS0))= $7431 savings !!!
your mileage may vary

the Electrodacus SBMS0 route avoids the combiner box additional expense, so to me makes it more DIY compatible....no combiner box is needed when assembling and paralleling two solar PV panels at a time at the array >>> (only 2-4 dollars for each set of parallel branch connectors)...

the combiner box(s) will increase the expense a lot when running high-voltage lines from the solar PV array. If you go with the 48-volt system, multiple BMS's,, and series connect the solar panels at the PV array..... just add up the price for the combiner box(s) for 60 290-watt PV solar panels and you will quickly find this huge expense that is not needed.

I routinely use a 32Amp DC rated breaker for each 2 paralleled solar PV panels inside the insulated solar power shed near the batteries and inverters, etc....

some will have difficulty understanding all the nuances of the SBMS0 but learning is the 1st and most important part....

sounds like they are shipping them tomorrow (the 64 lf280k version 3 battery cells) from Houston, Texas)
in the USA they have a 30 percent federal tax credit which will decrease the final cost for the ESS expansion even more which is another side benefit.
more later after the battery cells arrive
???

 

[michael d]

My December 2023 post in a different thread on DIY solar forum below:

I just ordered 32 cells with double busbars through Alibaba. The price was less than the Lishen cells and I ordered them with the welded-on screw holes, 20mm long m6 set screws, and serrated flange nuts. It will be about 60 days or so before they arrive.
I will be assembling a 32-cell 280Ahx4cells=1120 Ah battery at 25.6volt nominal using 32 cells 4P8S.
The total cost was $4243.19 including their service tax/fee delivered to South Dakota USA.
This makes the average delivered price = $132.60 dollars per 3.2Volt Eve LF280K cell.
3.2x8=25.6 nominal volts.
280Ah x 4 = 1120 Ah in parallel groups of 4 cells.
1120 Ah x 25.6 volts = 28,672 Wh battery potential capacity. they are reported to have more than 280 Ah capacity potential.
The plan is to use the Electrodacus SBMS0 as the BMS.
All will be off-grid.?

the above post of mine >>>>these I bought in January 2023 so the December 2023 eve lf280k 64 cells I just bought for $6615 with more free accessories was definitely less expensive than the 32 I purchased in January 2023!!!!
6615/64 = $103.36 per cell for the new LF280k version 3 cell with more accessories included....
the prices go up and down but these 64 cells are already in the warehouse in the USA so delivery will be fast...
nice to get them a bit less in these times of inflation
???

 

[kromc5]

I would be hesitant to go 8 parallel but but my 4p16s x 4, 2x parallel but have been spot on for over a year. Definitely upload
some pics I would be interested to see the build.

 

[michael d]

I would be hesitant to go 8 parallel but but my 4p16s x 4, 2x parallel but have been spot on for over a year. Definitely upload
some pics I would be interested to see the build.

the 64 version 3 cells are scheduled to arrive on Monday 1/1/2024. they were shipped from a California warehouse... via FedEx.
my 32-cell builds have been working without issue also.....
4P8S I have 2 of those and 2 of the 2P8S builds that have been running for about 2 plus years... in 25.6-volt nominal configurations...
my solar power shed is full but I will try to get some more recent pictures....

I have used Lischen brand 272Ah cells in the 16-cell 2P8S configuration 25.6 volts nominal.
and EVE brand lf280k in the 32-cell 4P8S builds at 25.6 volts nominal.

I use 400 amp class T fuses and added a disconnect switch on the 32-cell build on the negative 4/0 cable.

the 64 cell 8P8S is still in the design phase... waiting on some parts ( the cells)?

when assembling the 32-cell 4P8S builds >>> I was very hesitant but never had any issues until adding the 400 amp class T fuse.... and I believe the capacitors from the previously attached LF inverter kicked back at me ( a spark ) so out of caution/ respect / fear I added the disconnect switch on the negative 4/0 cable and no more spark....
I was on a ladder in an awkward position when that spark brought the fear of the almighty to rethink my need for additional safety measures. As I let the 400 amp class t fuse go sailing through the air.... this is one of my actual dum dum things that caused me to gain more respect for electricity and the need to learn more....

I definitely wear lightweight gloves and safety glasses as I work with the high amp 25.6-volt battery bank assemblies...!!!!!
please be safe always....
I am not an electrician or an electrical engineer.....
thank you for your reply!