Eve LF280K 6000cycle rated for solar at .5C 32cell build

[michael d]

Panels are constant current sources not constant voltage so they will automatically drop to battery voltage when connected by the DSSR20.

So, 2 of the 60 cell 250-watt panels connected in parallel then connected to an Electrodacus DSSR20 (a solid-state relay with some other electrical genius built-in) charges the 24-volt LiFePO4 batteries great.
Electrodacus SBMS0 controls the Electrodacus DSSR20's so the expensive LiFePO4 battery is not overcharged and hopefully gets a long life without any problems.

There is no high current going through the Electrodacus SBMS0, on the contrary, only small 26 AWG sense wires between the Electrodascus SBMS0 to control the Electrodacus DSR20's which are also low voltage low amperage components. all the solar panels are connected to the Electrodacus DSSR20's using 10 AWG solar PV wires. Every two panels are paralleled together at the array, then 10 AWG solar wires to a 32 Amp breaker, then onto the Electrodascus DSSR20's which are connected to the battery busbars to charge the large LiFePO4 batteries.

the Electrodacus SBMS0 turns the charging off when any cell reaches 3.55 volts for a preset time ( I will have to look that preset time up for you all later).

I have one 32-cell Lishen battery build (32 272Ah cells in a 4P8S configuration) being charged with 2 of the used 250-watt 60cell PV panels (purchased in 2 pallet quantities for cheap), no problems except need more panels to charge faster ( the future will get that done)!

I have two 16-cell Lishen battery builds (16 272Ah cells in a 2P8S configuration) being charged with 6 of the used 250-watt 60cell PV panels (purchased in 2 pallet quantities for cheap also), these two batteries charge considerably faster, and often before noon, the battery is completely full and then I try to use more of the solar energy!

I run lights 24/7 in the off-grid solar power shed to keep things above freezing, although the 3 LF (low frequency) inverters are generating heat (likely enough) all by themselves. It is 12 degrees Fahrenheit outside with finger-biting wind and it is 65 degrees in the solar power shed this morning! I will be adding more electric hogs in the future which put out waste heat also!

On a sunny day, I start using more electricity even before the sun gets to the solar PV arrays as I know a lot will not be used. later I am assembling a water heating system to utilize the excess solar electricity generated by utilizing the diversion capability of the Electrodacus SBMS0. the goal is to be totally off-grid with solar electricity as the main power.

This new battery build is with 32 of the EVE LF280K cells in a 4P8S configuration.
So this battery build will be 3.2volts(nominal for calculations) per cell x 280Ah x 32 of these EVE LF280K cell = 28,672Wh potential capacity although it will be more than that at 1120amps.

These cells are rated at 6000 cycles and have welded on threaded terminals so I will use the set screws(aka grub screws) with serrated flange nuts method to parallel and series connect these cells together. the website specifications have them at a slightly larger size and weight than the previous generation 3500 cycle EVE cells.

I will likely not draw more than 250 to 350 amps at one time in the solar setup.

It is cold outside, so warming up with a bit of hot coffee made off the solar-generated electricity!😎

gotta go,,, excuse any typos,,, will check back later!😎

 

[michael d]

Winter is upon me in South Dakota doing the solar battery bank and solar PV panel expansion. man,,,,, I have a love-hate relationship with the cold. no pesty insects and not too hot to sweat to death only frostbite to your fingers! in South Dakota. perhaps I can get to my Bolivia mountain getaway in February or so. it is now summer in Bolivia where we are planting some grapes and making more arcs on the rooftop garden next to the river. I have had grid power there now for the last 3 years. Good morning USA
I will be out to work on the new 32 cell EVE LF280K 24volt battery build in the off-grid solar shed once the sun comes up. the wind is howling so likely minimal outside activity in South Dakota this fine winter day. the picture below is my Bolivia home build >>>21 years and counting for this remote mountain build. The first 18 years without any grid power so definitely off-grid with only generators, candles, and kerosene lights.

 

[michael d]

I just received the Zketech EBC-A40L :

EBC-A40L Electronic load Battery capacity tester 40A 110V (139.65, 81.40 shipping, 14.36 vat= 235.41)

this will enable me to more accurately charge and test the new EVE LF280K cells for the 32 cell 24-volt build.
it is snowing hard today so not sure how much outside stuff I can do... have to make more room in the solar power shed.
an off-grid build but it was about 65 degrees inside earlier. a good winter project to continue on.
ordered on 12/6/2021 and received from China thru AliExpress today 1/14/2022; so about 39 days >>>as expected!
the box arrived in better condition than the still I bought shipped within the US.
go figure...
some of those shippers must just toss the stuff to see how much damage they can cause? huh
more later 😎
time to find the broom for the snow, but I did get a gas-powered blower >>>maybe I try that to remove the snow from the PV panels! 🤔

 

[michael d]

well the Zketech EBC-A40L had a loose screw inside, so I had to open it up, then it was actually a loose screw inside of the power supply so I had to take it loose to open it up. it luckily was a screw that would fasten the power supply to the case of the power supply. about 2 hours later and 35 or so tight little screws and 2 void warranty seals it is back together!

 

[michael d]

Inverter cable sizing help for me and possibly you too!!!!
i have been making 4/0 copper inverter cables which are likely plenty large for some smaller inverters, but i finally got the light in my head go off >>>> that on the 13000 watt LF inverter that 4/0 cables seemed to be adequate as the 4/0 copper cable current carrying capacity has a 423 amp rating.

13000 watt inverter draw divided by 48-volt equals 270.833333 amps
it makes more sense to me now.. probably wont be using quite that max pull from the 48-volt inverter anyways (at this time)!!!!

let me know if you think other wise and why???
cheers all... time to go out side this fine sun shiny day 😎

 

[michael d]

what size cable for 8000-watt LF inverter? another common size at 24-volts battery input as that is common also?

if it puts out 8000 watts?

often the cable is sized for the pull from the battery, so 8000 watts inverter draw divided by 24 volts = 333.333333 amps WOW.
but a LiFePO4 24-volt battery is a lot higher voltage in all reality: 3.2 x8 = 25.6 volts
mine rarely get below 26 volts and closer or above 27 volts most of the time on 24volt builds
so 8000watts LF inverter draw divided by (say) 27volts = 296 .296296296...amps >>>>still a lot of amps from a24 volt inverter... so big cables are required...

3.55volt x 8cells = 28.4 volts when my LiFEPO4 battery build is at 99 percent full (SOC) state of charge. at which time the electrodacus is preventing the DSSR20 from charging the battery any more.

what size DC fuse??? it seems fairly obvious to me that the 400 amp Class T fuse would be the fuse of choice to match up to the 4/0 copper cables between the large inverters and the battery bank....

fuse size is often said to use a general rule of thumb 1.25 or 1.56 x the expected /potential draw (lots more research and typing to tell you where those numbers come from). later for that topic...

At any rate 333 x 1.56 = 519.99999 hmmm hmmmm hmmm
3.33 x 1.25 = 416.6625 amps fuse sizing to max out the 8000watt inverter draw at which point the fuse blows...
better not go over 8000 watts on 24 volt system with 400 amp class T fuse with 4/0 copper cable

more research needed....

if the LiFePO4 battery stays closer to the 27volts as it does in the flat part of the discharge curve during normal use the figures:
8000watt LF inverter draw divided by 27volts equals 296.296294 Amps
then 296 x 1.25 = 370 amps so the 400 Amp class T fuse is still a good size....
to protect the wire and hopefully the inverter as well.....

the inverter is best protected by not getting it too hot for too long ,,,,, so keep it cool add fans to draw the heat away..
keep in in a temp controlled room ....70 degrees Fahrenheit is good,,,,, 72 ok ....
the higher the ambient temperature the harder the fans have to work to try to cool the inverter to prevent its failure.

more later....😎
time to go feed the critters at the off-grid site...
DC is dangerous so be careful in all you do and add appropriate disconnects, wear eye protection, and gloves.
gloves are a difficult part when working with some of the pieces and parts for sure....🤔

another light goes off for my research on proper sizing of things: most everything seems to be quoted at 25 degrees C which is actually 78 degrees Fahrenheit... because I was always taught the Fahrenheit system of temperature I always think in Fahrenheit... but in all reality, the metric system is so much easier and essentially all the scientific calculations are don with the metric system...

the edit is that a temperature-controlled room for everything around 78 degrees Fahrenheit may be better and easier to obtain in hot climates.... and not totally unreasonable in cold climates with a properly insulated building....

 

[michael d]

another thing to note is an 8000watt LF (low frequency) inverter is likely 88 percent efficient......ballpark figure.

so .88 x 8000 = 7,040 watts output from the inverter on the AC of things....

a 12,000 watt LF 48-volt inverter at 88 percent efficiency would realistically put out 12000 x .88 = 10,560 watts ( on the AC side of it).

I will be sitting up a 48-volt LF inverter this spring ( it is just around the corner.....) what happened with the groundhog and his shadow?
I have to make up some more 4/0 copper cables for the battery bank 1st....

the plan is to put some 24-volt battery build together with thick copper bus bar & cables to make a 48- volt LiFePO4 battery DIY style..
down on the off-grid farm.... yea ha!

I can see some reason for 48-volt is the inverter, and output, and cable fusing size, etc to utilize some in 48-volts.
but with higher voltages, better thicker safety equipment is needed. I have that.

the point being is not all equipment is safe and suitable for the 48-volt setups.... so do your research....carefully.
please take your time and be safe in all you do...😎

 

[michael d]

I bought a more accurate scale to weigh the new EVE 280Ah LF280K cells rated for 6000 cycles. (just out of curiosity!)
the EVE LF280K cells are physically taller than the Lishen 272Ah cells.
Are the EVE 280Ah LF280K cells better than the previous versions???
hard to say for sure until 6000 cycles which is about (6000 divided by 365 = 16.438) 16.44 years from now if they are cycled 1x per day.
the solar charge and discharge are a low C-rate so gentle for the large battery bank I am building...
more later,😎

 

[michael d]

I am using the 25mm long set screws and nickel-plated buss bars for the parallel top balancing using the RIDEN 6018 power by my other LiFePO4 batteries which are all off-grid and being charged daily by the sun...
on cloudy days there is less PV from the solar PV panels but it still charges the batteries until the full sun comes around...

on the EVE 280Ah cells, I parallel 4 cells together to charge at one time..
it takes about 2 days to top balance them... 4 at a time with the RIDEN 6018....

slow but sure... I could do it faster but I do not want to babysit it too much...
the RIDEN 6018 charges at constant voltage and when it gets to the pre-set voltage the amps just start decreasing then it shuts itself off. easy peasy!

I charge them to 3.55 volts as that is 99 percent of full....close enough for me....
I leave them paralleled until I do the series connections later.

More later...

maybe I will find a few pictures for you all,,,,later, tomorrow, maybe....🤔😎

 

[michael d]

I am using LF (low frequency) PSW (pure sine wave) inverters that are true split phase (SP). they have claims of 8000 watts continuous but not likely,,,,to do that amount of draw from them...
the next issue is proper disconnect and wire size to the 100 amp panel from the inverter I think I used 4 AWG copper cables,, have to double-check that...
the inverter has built-in AC breakers... CHNT brand...
right now only using120 volt 20 amp ac circuits but will try the 240 volts later on out of the Square D QO main panels....
this is strictly off-grid and not connected to the government-subsidized electric grid monopoly in any way whatsoever....

8000 watts divided by 240 volts = 33.333amps on the AC draw side of things...
8000 watts divided by 120 volts =66.667 amps on the AC draw side of things....

breakers are rated to run continuously without tripping at their faceplate value, but the Square D QO trip fast if there is a short....which is a good thing....
breakers are sized to protect the wire in the AC circuits.... my 20 Amp circuits use 12 AWG romex .....

Thankfully, I do not have to deal with the safety problems of imported HF(High frequency) imported inverters with or without the neutral ground bond issues.
the SP inverter transformer is not connected that way at all...
More later, just thinking out loud to myself as I try to provide some details of the off-grid build using LIfePO4 battery cells the DIY way....
Cheer all....😎

 

[michael d]

I have been sourcing some thick tinned copper bus bars to make a bigger battery possibly a 48-volt battery using 2 of the 32 cell batteries so then I would have a 64 cell battery using 64 EVE LF280k cells or maybe use the Lishen 272Ah cells... not sure yet but here is a set of the 4 inches by 12 inches by 1/4 inch thick bus bars I bought second hand.... see picture... the 32 cell (4P8S) 1044Ah Lishen has been functioning flawlessly for over 16 months now. with the Electrodacus SBMSO balancing it as it is charged daily via the Electrodacus DSSR20's.

 

[Justeric]

I have ordered the same cells 1p16s then another set in parallel I noticed one cell at 0.02v and the daly bms keeps on going off. What could have caused this

 

[michael d]

I have ordered the same cells 1p16s then another set in parallel I noticed one cell at 0.02v and the daly bms keeps on going off. What could have caused this

get a multimeter and check the voltage of each cell
turn off your load immediately (inverter or what ever is pulling the battery down
I suspect you have a bad connection (between cells ) or a faulty BMS.

 

[michael d]

get a multimeter and check the voltage of each cell
turn off your load immediately (inverter or what ever is pulling the battery down
I suspect you have a bad connection (between cells ) or a faulty BMS.

the lowest you want a cell to go is 2.5 volts for lifepo4 and you really do not want them to go that low. send a picture of what your doing....

 

[Justeric]

After I check with the multimeter the battery is at 0.02v. Confirmed the connection to the bms all is well done.

 

[Justeric]

The bms keeps on disconnecting the batteries I guess because of this one cell

 

[Justeric]

See attached cell 15

 

[upnorthandpersonal]

The bms keeps on disconnecting the batteries I guess because of this one cell

Take it out, and charge it on its own with a power supply - and hope it gets back to above 2.5V asap.

 

[Justeric]

I tried with the ac inverter (bypassing the bms) maybe I try this method

 

[michael d]

i think you should pull that one cell out and charge it separately as upnorthandpersonal suggests....