New LFP Cell Capacity Expectations

[sunsurfer]

I'm reminded of an old saying 2 is 1 and 1 is none. But in this case, perhaps A is B and B is C. If you don't want "C" grade cells(if there is such a thing) and your fine with "B" grade, order "A" grade.

 

[riverbug]

I now understand more about the topic of Grade A vs B cells and why some say it's just marketing and there are no differences. Sounds like it would be better if they just categorized as Certified EV vs Storage Grade or something. Then within Storage Grade they could put actual test results on the label and group them for sale based on actual results such as (for 280Ah for example) <270Ah, 270Ah-280Ah, >280Ah, etc., and price accordingly. Seems like that would help the buyers and sellers. But in the absence of that sort of system, I thought this was interesting to find on the 18650 site for Grade B cells the following statements which explain their take on the cell grades and perhaps explains the price and warranty differences between A (+$45 per cell with 1 year warranty) & B (-$45 per cell and 30 day warranty).

"Grade A and Grade B refer to the quality or performance level of lithium iron phosphate (LiFePO4) prismatic batteries.

Grade A batteries typically have a higher energy density, longer lifespan, and better performance in high-temperature environments compared to Grade B batteries. They also have a higher initial capacity and a lower internal resistance.

Grade B batteries, on the other hand, are generally less expensive and may be more suitable for certain applications that do not require the highest level of performance. They may also have a shorter lifespan, lower energy density, and lower initial capacity than Grade A batteries."

However, it states they test and match voltage, capacity, and resistance on both grades, but only grade B includes a statement that 280Ah+ is guaranteed. Perhaps that isn't stated on grade A because a report is available, not sure, but interesting omission for the one cell you would expect to see it on given the price difference.

Lots of people on this forum maybe already know this stuff, but it's a huge learning curve for me. Thought I'd share in case there are other noobs researching the same topics.

 

[Alkaline]

Riverbug, that is nice and all but you forget the power of cheap price, its like a drug and can distort your vision, I mean 4 cells at just 400 how bad could they be, I don't need all the AH.....

Yes cells with test report will give you the assurance you have bought quality products, but for the vast majority of DIYers we are looking to get the best value and the Chinese know it so they play along and say what we want to hear to get the sale. We should know better but we don't...?

 

[John Frum]

I now understand more about the topic of Grade A vs B cells and why some say it's just marketing and there are no differences.

Who says that?

 

[timselectric]

The "A" and "B" grading is done by the individual sellers. There are no industry standards for this. One seller might call a batch of cells "A" grade, because it's the best cells they offer. Whereas another seller would call the same batch of cells "B" grade, because they have better cells in their offerings.
It's just marketing done by the sellers. Not by the manufacturers. They don't grade their cells in this manner.
Because of all of the confusion created by the sellers, EVE has begun placing a "B" on all of their cells that are sold to the aftermarket sellers. In hopes of stiffling some of the confusion. But I doubt that it will help. The aftermarket will just find some other way to spin it.
Reviews and recommendations from trusted sources is the only way to know what you need to know about any cells being sold.
The best advice I can give is do your research, before you spend a penny.

 

[toms]

Unfortunately, people need to find out the hard way that you don’t know how much your batteries have cost you until the end of their lifespan.

 

[riverbug]

Who says that?

I rest my case...see the next post.

 

[riverbug]

The "A" and "B" grading is done by the individual sellers. There are no industry standards for this. One seller might call a batch of cells "A" grade, because it's the best cells they offer. Whereas another seller would call the same batch of cells "B" grade, because they have better cells in their offerings.
It's just marketing done by the sellers. Not by the manufacturers. They don't grade their cells in this manner.
Because of all of the confusion created by the sellers, EVE has begun placing a "B" on all of their cells that are sold to the aftermarket sellers. In hopes of stiffling some of the confusion. But I doubt that it will help. The aftermarket will just find some other way to spin it.
Reviews and recommendations from trusted sources is the only way to know what you need to know about any cells being sold.
The best advice I can give is do your research, before you spend a penny.

Agreed. I wasn't justifying any of it. I was just saying I have a better understanding of the grading now than before and used 18650 as an example of how they specifically categorize the cells they are selling. Before reading this forum and researching I assumed the grades were standardized across the reseller market; I know now that isn't the case.

For 18650 the grading seems a bit more valid because they apply a price along with warranty difference on cells according to their confidence in how those cells will perform compared to one another. Could still be marketing, but based on my research (as you suggest) the best I can assume is that I might get a bit more out of their grade A cell over grade B cell. But wouldn't ever know if I don't buy both and compare, and it hopefully would be years down the road before I have any longevity results.