LF 280 and LF 280K cells

[toolguy]

Hello,
Last year I built a small off grid system in my garage which works well but not large enough. I have been away from solar and this forum for about a year and have a question that I have not seen discussed. I purchased 8 Eve LF280 cells from Jenny Wu in October 2021. Purchase went well and I built my 8s battery which has been performing like it is supposed to. I am thinking I would like to double the size of my battery, but it is looking like I may not be able to easily find grade A Eve 280 cells here in the US. Aside from the dimensional differences and the threaded blocks on the top of the 280K cells, is there an operational reason why I should not add 8 LF280K cells to my current battery? I am currently using a Daly 200 amp BMS. My idea would be to build a 8s2p battery by pairing up the current 8 cells and then pairing up the new LF280K cells together but I don't know if they would charge the same. I also see the cost has gone up quite a bit and there appears to have been some bad experiences with Docan recently. I plan to add more panels which I already have so making the power is not the problem, but storing it is, though.
Any thoughts or suggestions would be appreciated. I am a beginner at this and my goal is to run my garage off grid. This is just a hobby project, I am not depending on it for survival. Please do not get too technical or it may go over my head, as I am not nearly as smart as the other members on this forum.
Thank you in advance!

 

[42OhmsPA]

Reports of 280k not meeting capacity, you'll likely get under 280 but nothing crippling.
I would not parallel the cells.
I would pick up 2 JBD or JK BMS's and make two batteries, then parallel them. 1 new 280k, 1 old 280 with upgraded BMS.
I have no first hand experience with the 280k, Daly, or JK; only regurgitating what I've read. I am pleased with my LF230s and JBD's.

 

[DIYrich]

18650 battery gets new stock of lf280k on a regular basis. I got 16 with the end of May shipment they received.

I wouldn't parallel old and new batteries on the same bms, especially if they are slightly different.

 

[Phil.g00]

BMS capacity aside, and assuming all cells are healthy.
I think you would get away with paralleling an old cell with a new cell at a cell level, as opposed to parallel strings. ( with a single adequately rated BMS).
If you were to run things as parallel strings then a second BMS would be needed.
I think you would run into trouble when you put an old one with a new one in a single series path.
This could be tested with a ZKEtech battery tester on an old+new cell combination.
My opinion is that it would just respond as a single larger-capacity cell. I don't see how the combo can behave otherwise.

 

[Horsefly]

Almost 3 hours, and we are yet to hear from @Alkaline? Seems odd. I think he has some opinions on this subject...

 

[toolguy]

Thank you all for the input. Several different opinions! My plan was to parallel the old cells with old cells and new with new. So basically I would have two 12v 560 amp batteries in series. I did find that there is a LF280N cell which appears to be almost identical to my current LF280 cells. To me, those appear to be a closer fit, if I can find them. My biggest concern is possibly damaging the BMS or cells in some way.

Right now I am running a refrigerator and freezer constantly, and with the drain from my 4KW inverter the battery is at about 65% by the time the sun starts charging again in the morning. If I run an AC for a few hours during the day the battery will still charge to about 100% by late afternoon. I have the capacity in my Victron charge controllers to increase input by 50% and with a larger battery I could run the garage for two days without sun.

This is as much a learning experiment for me as anything else, so the end cost of the upgrade will have a bearing on it. I was hoping to continue using my current BMS to run the new, larger battery since it has the capacity, rather than buy two new BMS. I do have two identical Victron controllers on separate sets of four panels each, which I plan to increase to six panels each, so if I did need to build two separate batteries I could put one battery on each controller.

Any other suggestions would be great! Thank you!

 

[Alkaline]

Almost 3 hours, and we are yet to hear from @Alkaline? Seems odd. I think he has some opinions on this subject...

Actually I'm pretty much done with it, however, I am waiting to see these new 280K V3 versions. They have new Pentagon shaped terminals. Maybe EVE finally fixed their mistake and now the 280K will perform like the original 280N, getting 290A plus on a regular basis.

Either way if grade A 280K pulls in the 290s then grade B can be expected to pull in the 280s.

But in the END eve screwed up with the 280K, should have called a the 270K it was new high life chemistry for them. The part that is sad is that they just ignored the hole mess and swept it under the rug.

 

[EastFalcon]

I have 8 cells from 18650batterystore LF280K grade A with dual terminals.
I tested 4 of them in my sfk v4 kit and I got 278AH.

At first I was depressed about this because the image on the website showed cells testing to 295 so I am 13 AH short, but I'm thinking without the eve's own tester we can not reach these ratings.

However, I realize that it is only 2AH and the cells I have stay in balance look nice and performing nicely so loosing sleep over 2AH is foolish.

I am building my second kit soon.

According to the QR scanner app my cells were all made in October 2022.

If capacity is the most important factor for you, then maybe get some 300 AH rated cells. Rept 280 Seem to be nice as well.

 

[toolguy]

Thank you everyone for your input!