Have You Found The Cell Database Helpful?

Have You Found The Cell Database Helpful?

  • Yes, It Has Been Helpful

    Votes: 22 88.0%

  • No, It's Not Helpful

    Votes: 0 0.0%

  • Haven't Used It

    Votes: 3 12.0%
  • Total voters
    25
Sad to say, I haven't used it...... Yet

I actually plan on starting to use it in the next week or two as I'm pre-charging my next batch of cells right now. I have 900 cells or so total that I need to start sorting. I know, I know, I should of been sorting from the beginning. But I gotta find something to do when I'm bored at home :p
 
Very very handy. I use it all the time, whenever I find a new cell. So far aside some strange Chinese cells, it hasn't failed me yet. For the cells you don't have datasheets for, I have been unable to find them anywhere else on the net.
 
Very helpful
Im selecting cells using tested capacity as a percentage of original capacity as well as tested capacity.
To me if two cells test at 1900mAh and ones original capacity was 2200mAh and the other 2800mAh the one with the higher percentage of original likely has more life left.

Im sorting into 100mAh buckets and then ranking as percentage of original capacity.
Must admit if a cell is xx9xmAh it gets pushed into the bucket up :0
 
I use it a bunch. Great help in identifying Cells
 
Jon said:
Very helpful
Im selecting cells using tested capacity as a percentage of original capacity as well as tested capacity.
To me if two cells test at 1900mAh and ones original capacity was 2200mAh and the other 2800mAh the one with the higher percentage of original likely has more life left.

Im sorting into 100mAh buckets and then ranking as percentage of original capacity.
Must admit if a cell is xx9xmAh it gets pushed into the bucket up :0
Click to expand...

I've been thinking about that too and unless you track each cell type and know what it's original capacity was then it doesn't really matter where the cell came from. If it has 1900mAh then great!

Now where having the knowledge about what the original cell's capacity was may help you in determiningtherest of the cells life but then again I'm not sure. If a cell is at a 1900mAh point in it's life curve then how does that differ from a brand new cell with 1900mAh and a well used cell with a original capacity of say 2900mAh, will the old cell die quicker if it's used in the same way as the new cell, within the cells tolerances obviously. If you keep charge and discharge rates low then should the two 1900mAh tested capacity cells not behave the same over time?

Has anybody tested that yet?
 
To be honest, I haven't used it because I knew it won't be of any benefit to my project. To me, the specs of the cells when they are new are not relevant because they aren't valid anymore anyway.
 
DarkRaven said:
To be honest, I haven't used it because I knew it won't be of any benefit to my project. To me, the specs of the cells when they are new are not relevant because they aren't valid anymore anyway.
Click to expand...

This is largely true. However the original specs give a good idea of how 'worn' the cell is. If a cell is a lot less (like 50%) than its original capacity, I tend to set them aside. They usually have issues with self discharge.
 
Yeah I don't really care how worn they are. That's why I test the cells, I'll know when some have issues with self discharge. And the largest cells are around 3000mAh new anyway, I haven't used any under 2000mAh yet so 66% remaining capacity is the minimum my cells have.
 
Geek said:
DarkRaven said:
To be honest, I haven't used it because I knew it won't be of any benefit to my project. To me, the specs of the cells when they are new are not relevant because they aren't valid anymore anyway.
Click to expand...

This is largely true. However the original specs give a good idea of how 'worn' the cell is. If a cell is a lot less (like 50%) than its original capacity, I tend to set them aside. They usually have issues with self discharge.
Click to expand...

That's a good point Geek, but do we know if the cells degrade in a linear fashion over time or do they fall off a cliff at some point?

If the degrade in a linear fashion(which I think they do) then we can essentially ignore what the cells original capacity was as it doesn't really matter as they will degrade the same, or will they?

Does a new cell have a different rate of degradation than a old cell I wonder?

If they all degrade with the same rate then it doesn't matter and we can simply test the cell at X mAh and match them by that number alone and they should degrade the same over time as long as we don't exceed the original capacities of the cells but I don't think we need to worry about that in most cases for powerwalls as we all put in as many cells in parallel as we can to extend the overall capacity of the whole system, that lowers the charge / discharge rates to well below each cells tolerances anyway.

Maybe I should try and test the degradation of a few new and old cells and see if there is any major differences in the rate of degradation for similar capacity cells, I'll have to make up a small test-rig that I can leave running for a long time so I'll need to get some parts first...
 
Have not used it myselve yet, still voted for helpful... :)
It is a goldmine, and i gonne need it sooner or later.
 
use it all the time when looking to buy cells off others
 
Use it all the time. At least a couple times a week. Like Keith said unless you like to search the web. Saves me a lot of time.
 
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