Indeed 76€ each i payed got them from Tuesday morning
Just 4 cells to test em out
Cell prices coming down
- Thread starter GuyG
- Start date
Just 4 cells to test em out
Sverige
A Brit in Sweden
Will be really interesting to hear how they are, if you wouldn’t mind sharing your opinion once you’ve tested them.
B grade based on a slightly low capacity is one thing (not really a problem), but if they show varying internal resistances or any cell starts showing excessive self discharge, that would be a reason to not dive in and buy more.Indeed just testing em for fishingWill be really interesting to hear how they are, if you wouldn’t mind sharing your opinion once you’ve tested them.
Not capacity testing no need for 5more or less then described haha
I’m happy as they stay at the same voltage with my daly bms ?? otherwise active balancer is added
I believe NKON will replace a cell that shows that kind of behavior. From their site:
"B-grade cells are cells usually did not qualify as A-grade by the manufacturer. This may be due to optical imperfections, higher self-discharge, lower capacity and/or higher internal resistance. Unfortunately manufacturers don't tell which aspects or aspects are the reason to mark a a specific cell as B-grade. We have sold several and get seldom negative feedback. We tested several eve B-grade and one had about 2% lower capacity, the other ones we did not find a difference with A-grade cells. We don't advise B-grade for high performance electric vehicles but for home energy storage they will work fine. In case you get one which performs significant less than the others like lower capacity, high self-discharge or fast wear we will replace it. Take care that we don’t put a lot of trust in a simple test of a single cell, if you buy 16 cells and you test them and they are all 6% lower than expected then your test gives to low results. If you buy and test 16 and 15 cells give you 100% and one cells gives 5% lower results then we will replace one. When we buy cells the cells are tested for voltage and internal resistance. Also a couple of every batch are tested for capacity, and if one gives less than 100% capacity we test the whole batch and discard the bad ones or don't buy the batch at all. Lot of seller in china buy B-grade cells, test them, even swap qr-codes and sell the good looking and performing as A-grade cells. We believe our B-grade cells are the same as lot of A-grade cells from China, including the well known resellers there with good reputation. We give regular warranty on these cells (at least 2 year)."
houseofancients
Solar Wizard
they will
Sverige
A Brit in Sweden
Well then if those Envision cells have a similar rated cycle life to Eve cells they appear to be by far the best option in the current market. I said I’d wait for prices to come down further, but honestly I’m quite tempted now ?
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
NKON like a "FEW" others do have a rep for being honest and will replace defectives provided the tests are proper and you can show that. Some will not charge for S&H, some will while a "very very few" will just ship a replacement once proper proof is provided without requiring return of a defective cell. The GOTCHA of course is the "proper proof & testing" and how they define that while realizing members here are not test labs with all that gear.
I do believe that NKON is considered one of the Know Good Reliable vendors.
Things are Changing FAST...
Standard LFP prices are falling and will continue for a while.
The new Std LFP's in the 400AH+ Range are also starting to be released in Q1-2024 onwards from CATL, EVE and a couple of others... That will also cause a bit of a buying shift. Ultimately the smaller cell prices will drop ...
LMFP is climbing the production ramp at the major players, this is offsetting std LFP.
Sodium is now hitting wholesale, manufacture & RETAIL and I is moving really fast...
Solid State is also hitting commercial production but a way to go before retail...
Semi-Solid-State is not retailing but there are gotcha's there - Will discovered some of that...
BTW: When looking at cell pricing, NOTICE that cells Below 120AH are falling much faster than their bigger cousins and far more A & A+ are available now than ever before.
I WONDER & Maybe @upnorthandpersonal may know, have you or anyone else ever do a side x side comparison with packs using different sized cells to see how they charge, discharge (speed & behaviour etc) ?
Example for a comparison. Build two 24V or 48V Packs: One with 300AH cells and One with 100AH cells (yes 3P) {or 304AH & 105AH} and actually observe the entire Charge & Discharge process to determine the performance & resiliency of the 2 different packs. I did something like that and WOW, Interesting to observe, NOT what I expected (Assumed)...
I do believe that NKON is considered one of the Know Good Reliable vendors.
Things are Changing FAST...
Standard LFP prices are falling and will continue for a while.
The new Std LFP's in the 400AH+ Range are also starting to be released in Q1-2024 onwards from CATL, EVE and a couple of others... That will also cause a bit of a buying shift. Ultimately the smaller cell prices will drop ...
LMFP is climbing the production ramp at the major players, this is offsetting std LFP.
Sodium is now hitting wholesale, manufacture & RETAIL and I is moving really fast...
Solid State is also hitting commercial production but a way to go before retail...
Semi-Solid-State is not retailing but there are gotcha's there - Will discovered some of that...
BTW: When looking at cell pricing, NOTICE that cells Below 120AH are falling much faster than their bigger cousins and far more A & A+ are available now than ever before.
I WONDER & Maybe @upnorthandpersonal may know, have you or anyone else ever do a side x side comparison with packs using different sized cells to see how they charge, discharge (speed & behaviour etc) ?
Example for a comparison. Build two 24V or 48V Packs: One with 300AH cells and One with 100AH cells (yes 3P) {or 304AH & 105AH} and actually observe the entire Charge & Discharge process to determine the performance & resiliency of the 2 different packs. I did something like that and WOW, Interesting to observe, NOT what I expected (Assumed)...
A larger cell pack will provide a higher amount of energy (current delivered) than the lower cell pack - but they keep each other in balance: they come to the top and bottom at the same time. LFP is really nice in this regard.
Brucey
Solar Wizard
I noticed the big Trophy battery is now using 48 of the eve 102Ah? cells in 16S3P versus their previous model using 16 of the 304Ah cells. Makes sense with 18650 pricing for the 105Ah at $39+shipping now.
Did you find the 3P packs were more robust in performance?
Brucey
Solar Wizard
Is that still the case if we are comparing three 105Ah in parallel versus a single 304Ah?
Yep! They will all be in sync.
BentleyJ
Solar Wizard
Depends on how the connections are made. In a factory with an automated bus bar welder, multiple, less expensive cells may make sense. If you have to make all the connections by hand on a DIY project then single large cells make more sense.
Cost per Wh with larger cells is less than smaller cells (purely based on cell cost).
Is LMFP way better than LFP?
Also as a local diy seller in a third world poor SEAcountry, should I be worried about having a considerably large amount of LFP cell stock?
And thank you for your information sir!
(About 650 pcs)
Sverige
A Brit in Sweden
I’ve been advised in the past by chinese resellers not to parallel connect Eve 280Ah cells with my existing Lishen 272Ah “because the internal construction is different“. I consider that dubious advice but have never tried it anyway. I reckon the cells would not mind one bit.
Personally I don't put cells in parallel - I prefer each one to be monitored separately.
There might be internal differences, but for typical solar applications it shouldn't matter if you do.
Define better. Cell voltages are higher (4.2V iirc), but they have a better energy density. LMFP has a lower cycle life compared to LFP though, but it performs better at low temperatures. Initial research also indicates slightly less stable compared to LFP (but still safer than others).
houseofancients
Solar Wizard
Yet, there's no problem paralleling complete 16s packs, with their own BMS..
Agreed on not paralleling within a single pack
I would agree if they are talking about parallel under one BMS. If each cell type has its own BMS you should be able to manage it.
This is the diy battery sub forum, I don’t think any of us are using automated bus bar welders
I still don’t know that buying 3x the volume of 100ah cells, shipping, packaging, and assembling would be cheaper than 1/3 as many cells that are 3x the capacity even with automation. Because there’s still 3x the welding and 100ah cells don’t typically list for 1/4-1/5 the cost of 305ah cells
BentleyJ
Solar Wizard
My comment was in response to what @Brucey posted regarding Trophy using multiple lower capacity cells. Trophy is certainly NOT made up of a bunch of DIY'ers. I was simply stating that in a HIGH PRODUCTION FACTORY setting its possible if they got a super great deal on the smaller cells and automated the process it would possibly be less expensive for them and I stand by that statement. Has nothing to do with us DIY'ers.
This ends it for me. Not sure why a mundane issue like this has to be taken out of context and turned into a pissing match.
No pissing match intended, it appeared as though you were replying to me, your reference to the welding in regards to trophy makes sense to me! I just didn’t connect those dots on the prior page.
?
Brucey
Solar Wizard
It's getting close tho. Using 18650 for pricing, Eve 105Ah at $39, 304Ah at $109. The pricing for shipping wasn't that much more for the 48 cell 105Ahs either.
Doesn't seem long ago Eve 105Ah was $60 and the 304Ah $130 or so. The 105Ah seems to have dropped down much more percentage wise.
Sure, I was talking direct prices from the manufacturer at this point. Those smaller cells are being phased out - EVE already released a 560Ah cell.
