Best current deals for GOOD lifepo4 280-305 range cells
- Thread starter Herculezz
- Start date
hwy17
Anti-Solar Enthusiast
I'm not sure if if those count as reputable and good. They're B grade cells from a reputable seller. Wasn't there are a thread about one that arrived leaking? Idk, maybe I'm misremembering but I think some people have been unsatisfied.
I heard that 18650 took care of those cells and all was well? Also at this price point 75, I doubt there's much that beats it for quality cells, no I don't mean A grade or EV grade just that they meet or exceed their ratings which 18650 guarantees, and they are not used like half the cells you get from ali
hwy17
Anti-Solar Enthusiast
I'm still not sure about calling them quality but yeah they're of a known quality and 18650 is a legit vendor with decent record of satisfaction. If you're ok with B grade they are probably the best deal.
Partimewages
Solar Addict
Doesn't mean anything
If you expect a highway C load on the cells they may have undesirable voltage drop.
“May” being the key word.
Horsefly
Solar Wizard
It is a completely made up label from people on this board who think they are experts. There is no such thing.
HOWEVER: Everything you buy as individual cells is almost certainly cells that the original manufacturer couldn't sell to their intended customer, which is EV companies. So everything is not as good as intended. Dividing everything after that into "A" and "B" is completely made-up.
Ok so here is where I am at,, 32 Envision cells from 18650 for 2827, prolly get around Christmas ish, or 32 LF280k v3 which I hear are testing over 300, for 3078 from Jenny wu, China shipped would get probably around end of January, any thoughts, ideas, better deals?
hwy17
Anti-Solar Enthusiast
I have heard it's most commonly for physical spec failures. Not precisely square, wrinkle in the wrap, terminal not exactly flat, any kind of tiny dent, etc.
Alkaline
Solar Wizard
You can get a good price or you can get quality, but you can't get both.
18650 Grade B has a "Meh/Ok" Reputation
18650 Grade A has a "GOOD" Reputation
Personally I say pony up the cash and get the Grade A and get peace of mind,
Also checkout:
Batteryhookup.com they have 280K v3 in stock with test report at pretty good prices, note they have sales tax on almost every state except maybe Delaware / Rhode island
sunfunkits.com has a 48 pallet probably the cheapest grade A if you can wait 2 months
ezealco.com has some nice deals on grade A cells
Alkaline
Solar Wizard
Attachments
Horsefly
Solar Wizard
Yeah, that's perfect for what I'm saying! These are the manufacturer (Eve, probably) blocking out the data matrix, indicating that these cells are going to the gray market because they can't go to the EV companies. ALL of the cells we mortals can buy from any of the brokers in China (or the shops that resell from the brokers) are in this same category. This "B" has absolutely nothing to do with the arbitrary "A grade" vs "B grade" that the imaginations of the people here have created.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
When a CELL is A-Grade, that is tested & verified to be capable of delivering the rated Amp Hours from the Working Voltage Range (3.000-3.400) Volts per cell. Take an EVE-280K V4 "A" cell. It will deliver that 280AH from the working range and when tested from 3.650-2.500 will likely deliver between 290-295AH +/- from the entire "Allowable Voltage Range",
A grade "B" Cell (Which EVE marks onto the QR Code) fails that Deliverable Capacity from the working range. These will often test out at 265-275 AH within the working range but when tested for the Allowable range may deliver 280-285AH from 3.650-2.500
Additionally, the Internal Resistance is also tested in the cycle and the IR tolerance is pretty tight and again using an EVE-280K-V3 should be between 15-20 Ohms while B-Cells can be as high as 25 Ohms. This directly impacts the ability to take charge & discharge and one of the prime examples are "Runner Cells" which can either Run High when charging and reach High Volt Cutoff OR can drop voltage faster, reaching Low Volt Cutoff ahead of the other cells.
Matched & Batched Cells = Cells that are tested & matched for Capacity AND Internal Resistance. It is important to have cells with matching capacity & IR so that the entire packs works in harmony throughout the entire voltage range and with various loads/charges Light or Deep. If cells have different IR (greater than 2 Ohms) you will see voltage deviations at the edges of the working voltage range and worsening the farther out you go into the "allowable" range.
SPECIAL NOTE: Most Vendors do NOT Match & Batch but some will rely on the factory test reports to match up cells BUT NOT MANY, the vast majority will test the cells at the Storage Voltage (3.200 Vpc) as shipped from factory to determine the IR (this is false matching). The full cycle to Match & Batch requires a full charge/discharge cycle with variable loading and tested at .050 increments to match IR.s Companies like EVE, CATL, BYD will provide these reports for A-Grade cells.
NB: A FEW HAVE BEEN CAUGHT FUDGING FACTORY REPORTS (they have been outted here). Hence stick to KNOWN GOOD VENDORS !
FACT: Like ALL Battery Chemistries, there are TWO Voltage Ranges for the batteries.
Allowable Range is the range that will not cause harm/damage to the cells. This is from 2.500 to 3.650 Volts.
Working Range is where the Actual Deliverable Amp Hours comes from and this is the range tested in Cell Factories. This is from 3.000-3.400 Volts per cell. HENCE WHY NOMINAL VOLTAGE = 3.200 Volts ! You can safely use A-Cells from 2.800-3.400 and even charge to 3.500 (providing an allowance) for the cells to settle at 3.400 as LFP always settles post charge, chemistry fact.
FYI: Cells which have had their QR Codes "erased" and replaced are 99% of the time FAILED cells that do not even make B-Grade. These are Bulk Commodity cells that still work but failed either capacity or IR testing. The Bigger companies like EVE, CATL, BYD will NOT release these but will recycle them into remanufacturing. There are other companies out there (smaller ones) that will dump their Bulk Cells to Brokers who flog them onto vendors "cheap".
EV Cells... Funny part that few mention, Prismatic Cells (the big blue blocks) are NOT that common in EV's, the preferred format is pouch LFP or large format cylindrical (structural packs). Perfect Example is the BYD Blade LFP which is a long narrow pouch format. You will not see 500AH Prismatic Cells in EV's but will in Energy Storage Systems which are far less demanding. Also do note that if buying a Cheap EV Toy off Alibaba like those $4000 trucks or "Interesting Carts" they often come with either FLA Batteries or if Lithium they will use the standard prismatic LFP cells because they are the cheapest AND they rarely ever go beyond "72V" class (most are max 48V).
Alternate Realities & "The new Math" do not apply to chemistry & science which are fixed into facts.
A grade "B" Cell (Which EVE marks onto the QR Code) fails that Deliverable Capacity from the working range. These will often test out at 265-275 AH within the working range but when tested for the Allowable range may deliver 280-285AH from 3.650-2.500
Additionally, the Internal Resistance is also tested in the cycle and the IR tolerance is pretty tight and again using an EVE-280K-V3 should be between 15-20 Ohms while B-Cells can be as high as 25 Ohms. This directly impacts the ability to take charge & discharge and one of the prime examples are "Runner Cells" which can either Run High when charging and reach High Volt Cutoff OR can drop voltage faster, reaching Low Volt Cutoff ahead of the other cells.
Matched & Batched Cells = Cells that are tested & matched for Capacity AND Internal Resistance. It is important to have cells with matching capacity & IR so that the entire packs works in harmony throughout the entire voltage range and with various loads/charges Light or Deep. If cells have different IR (greater than 2 Ohms) you will see voltage deviations at the edges of the working voltage range and worsening the farther out you go into the "allowable" range.
SPECIAL NOTE: Most Vendors do NOT Match & Batch but some will rely on the factory test reports to match up cells BUT NOT MANY, the vast majority will test the cells at the Storage Voltage (3.200 Vpc) as shipped from factory to determine the IR (this is false matching). The full cycle to Match & Batch requires a full charge/discharge cycle with variable loading and tested at .050 increments to match IR.s Companies like EVE, CATL, BYD will provide these reports for A-Grade cells.
NB: A FEW HAVE BEEN CAUGHT FUDGING FACTORY REPORTS (they have been outted here). Hence stick to KNOWN GOOD VENDORS !
FACT: Like ALL Battery Chemistries, there are TWO Voltage Ranges for the batteries.
Allowable Range is the range that will not cause harm/damage to the cells. This is from 2.500 to 3.650 Volts.
Working Range is where the Actual Deliverable Amp Hours comes from and this is the range tested in Cell Factories. This is from 3.000-3.400 Volts per cell. HENCE WHY NOMINAL VOLTAGE = 3.200 Volts ! You can safely use A-Cells from 2.800-3.400 and even charge to 3.500 (providing an allowance) for the cells to settle at 3.400 as LFP always settles post charge, chemistry fact.
FYI: Cells which have had their QR Codes "erased" and replaced are 99% of the time FAILED cells that do not even make B-Grade. These are Bulk Commodity cells that still work but failed either capacity or IR testing. The Bigger companies like EVE, CATL, BYD will NOT release these but will recycle them into remanufacturing. There are other companies out there (smaller ones) that will dump their Bulk Cells to Brokers who flog them onto vendors "cheap".
EV Cells... Funny part that few mention, Prismatic Cells (the big blue blocks) are NOT that common in EV's, the preferred format is pouch LFP or large format cylindrical (structural packs). Perfect Example is the BYD Blade LFP which is a long narrow pouch format. You will not see 500AH Prismatic Cells in EV's but will in Energy Storage Systems which are far less demanding. Also do note that if buying a Cheap EV Toy off Alibaba like those $4000 trucks or "Interesting Carts" they often come with either FLA Batteries or if Lithium they will use the standard prismatic LFP cells because they are the cheapest AND they rarely ever go beyond "72V" class (most are max 48V).
Alternate Realities & "The new Math" do not apply to chemistry & science which are fixed into facts.
Interesting and good to know. When you write 25 ohms, I assume you mean 0.25 mΩ (a quarter of a milliohm).
Last edited:
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
@ 4:30 AM when I replied, I likely just started my 1st coffee LOL...
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