Where to buy grade B cells?

[ericfx1984]

So my house build is going to be with the following cells

16x Eve 304ah grade A with 200a BMS
16x Eve 280ah grade a with 200a BMS

But I would like to increase my overall capacity... Probably getting close to twice the capacity that I currently have so I'm thinking that green cells might be a really good way to increase my capacity

But I have no idea where to get my great b cells from...

 

[Quattrohead]

18650battery store. They have REPT 280 and Gengfung 280.
I just got the REPT so putting them together this week.

 

[Alkaline]

So my house build is going to be with the following cells

16x Eve 304ah grade A with 200a BMS
16x Eve 280ah grade a with 200a BMS

But I would like to increase my overall capacity... Probably getting close to twice the capacity that I currently have so I'm thinking that green cells might be a really good way to increase my capacity

But I have no idea where to get my great b cells from...

So you started with grade A and now want to add grade B? Why would you do this, take it from somone that has had Both, I would not go back to grade B ever.

And anyone that has had both grade A and B will tell you the same. Its like going form Gas station sushi to an actual rated restaurant.

My grade A weren't even that much better than grade B capacity wise, but performance wise they whoop my basen and xuba 8s pack.

 

[Ampster]

And anyone that has had both grade A and B will tell you the same.

Not me. I did an EV conversion and used Grade A Winston's at over $250 per kWh. I now have a 42 kWh pack of Grade B cells in a stationary pack which cost less than $120 per kWh. It all depends on where you are standing and how you want to spend your money.

 

[Alkaline]

Well my 8s Xuba and 8s Basen pack are pia, require a heltec active balancer and the xuba has 2 cells that can not be discharged harder than 70A once the SOC goes below 70%.

I would gladly replace both xuba and basen for a single 8s grade A pack.

These are 280N EVE cells. I generally do not need the power but every now and then there is an amp demand of about 125 amps, originally each pack was meant to be able to provide the 125AMP but I had to scrap that and now run both these pack in parallel.

the luyuan EV grade 280K pack does the same duty by itself, doesn't complain and I even took the active balancer off it as the overkill solar bms is able to balance it just fine.

So to each its own.

 

[Ampster]

So to each its own.

I agree. It all depends on where you are standing. My pack is 3P16S, all Grade B cells. If there are differences, the parallel cells mask the differences. It is worth it to me to save maybe $75 per kWh In my case that would have been $3,000..

 

[octal_ip]

Sounds like @Alkaline has had particularly bad luck with his grade B orders. I'm running some grade B LF280Ks from Luyuan and couldn't be happier. I honestly wouldn't be able to pick the difference between what I have and grade A, they work flawlessly for me.
This is the gamble though - you trade cost with risk, and you can never be certain of what you'll get.

 

[billt1827]

And anyone that has had both grade A and B will tell you the same.

Not me.

Started with Winston 400Ah at £380 per kWh added EVE grade B 280K for £110 per kWh; the capacity is fine and haven't seen any performance issues. Although they are to increase capacity and aren't likely to exceed 60A discharge, which will be even lower when I get the next 2 banks of grade b EVE cells connected.

The next 32 cells are testing better than the first lot I had.

 

[Alkaline]

Sounds like @Alkaline has had particularly bad luck with his grade B orders. I'm running some grade B LF280Ks from Luyuan and couldn't be happier. I honestly wouldn't be able to pick the difference between what I have and grade A, they work flawlessly for me.
This is the gamble though - you trade cost with risk, and you can never be certain of what you'll get.

HA,

don't get me started.... see here: https://diysolarforum.com/threads/what-is-going-on-here-just-got-zke-40.49076/

as you can see my timing could not have been worse. I think part of the reason is when you buy the cells, I think these companies sort the cells, the grade B that are identical to grade A in performance, the you have the middle of the lot, and then laggers or cells that have issues.

So depending on when you buy you could end up with problematic cells, or if you get them early enough you could get some bargains. So although I don't have proof I think they start sending good cells to get the buzz going and then when the orders start coming in the bad ones get snuck in...

As for the 280K this was just a problematic cell regardless of its a grade A or B. Even the grade A were having a hard time getting 280AH of capacity.