Cell Cataloging and Data Sharing

Hello all,
I was just wondering if anyone catalogs their cells?

I keep a spreadsheet of every cell I am able to test. I record things like the make, model, tested capacity, any specs I can find on data sheets, etc. I thought that by doing this over time I could find some trends, maybe see which model#'s had the best characteristics. It also does some basic calculations.

I haven't cataloged the cells that could not complete a test cycle i.eheaters, self-dischargers, physically damaged cells

I thought some of you might be interested

Here's a link to my spreadsheet

Great work Droid ... we definitely need more information like this , The 'science' of recycling cells is still in it's infancy , many unknowns ...

What is particularly needed is an understanding of the way cells go bad , I suspect , in the way we use them in powerwalls , they don't suddenly go terminal in such a way as to blow a fuse ... more likely go into slow self discharge , if not spotted such a cell would slowly discharge all those in parallel with it , will have to be isolated or removed from the pack ...

If we can have some way of detecting those most likely to do this ,it will help greatly ..

I notice you reject even cells with a capacity of 1.7ahrs !! You're not the only person doing this , but I think it's a waste , also disposal is a problem , the scrap man won't take them , even as a gift! ... Most of the work is already done by buying the batteries , opening them up , testing , so why not put most of these you are now rejecting in second grade pacs , just to see if these lower capacity ones do fail first ... my bet is you will get many years of trouble free use from these rejects , and capacity is not really an important issue for stationary applications , those rejects will still have double the power density of a new lead acid battery , and I bet , last longer.

I break them into 3 categories in the sheet:

1. Viable Cells which I plan on putting in my primary packs I think I may go with 1700+ for these maybe 1800
2. Secondary Cells will go into my secondary packs and I'm thinking these will be 1300 or 1400 to 1700 or 1800
3. Useless Cells, these are Cells below 1300

This is all preliminary, these plans may change if I find a cheap consistent source of batteries

Recycling the dead ones isn't an issue there is a local recycling center that takes them

I divide my cells in 5 categories:

1) cells above 1900mAh (or above 82-84% of their nominal capacity) - these will go in my packs;
2) cells between 1700mAh and 1900mAh - these are for use in torchlights;
3) cells between 1500mAh and 1700mAh - these will be used for battery banks, for gifts to friends, or for (recently) two big packs for powering 2 wi-fi cameras in my place;
4) cells between 1000mAh and 1500mAh - don't really have any idea yet, but I just keep them;
5) everything below 1000mAh gets thrown away;

I test my cells at least twice - I have seen cells that read 1800-1900mAh on the first test, and on the second one the same cells comfortably pass beyond the 2000mAh mark.

Crikey a lot of work cataloging every cell. I would be into a sticky thread showing a pic of each cell type to show capacity and C rating.
I basically look for cells in descending order which is capacity. When I get a batch I sort packs into manufacturer then model of the batt then do the high capacity ones first, ie above 50000mAh. Saves a hell load of time only processing batts with the higher capacity first. I've just completed my assembly of 15 x 100 cell packs (14 and a spare to change any out for service) with all cells each better than 2300mAh. Does depend what volume of batts you get.
I have graded tested cells into buckets as follows;
<1800
1800-1900
1900-2000
2000-2100
2100-2200
2200-2300
>2300 went into the packs.

What I've found (going from memory) is;
Panasonic Grey 3000mAh
Samsung Light blue 2800mAh
Samsung Pink 2600mAh
SonyGreen 2550mAh
Newer Sony Orange 2500mAh
Sony Red (light blue ring 2500)
Samsung blue 2400
Panasonic purple 2500

Other batts >2300 go into a bucket and are not tested at this stage. These cells could be potentially sold to recoup costs or for other projects or expansion of system once I see how well this one performs constructed with only cells greater than 2300.

I should start a build thread!

i dont think it is in our best interest to "throw away" any cell that is somewhat usable, that might be partly a reason why i could use any capacity cell in my planned build, most cells i get are in 1900-2000 sphere anyway, so no massiv 2500 packs for me...

Droid126 said:

Hello all,
I was just wondering if anyone catalogs their cells?

I keep a spreadsheet of every cell I am able to test. I record things like the make, model, tested capacity, any specs I can find on data sheets, etc. I thought that by doing this over time I could find some trends, maybe see which model#'s had the best characteristics. It also does some basic calculations.

I haven't cataloged the cells that could not complete a test cycle i.eheaters, self-dischargers, physically damaged cells

I thought some of you might be interested

Here's a link to my spreadsheet

Click to expand...

Thanks for the link to your spreadsheet.

I also am cataloging the cells. Though I have not tested them all.
I am logging what the initial voltage was and then going through charging them.
I have an Imax b6 clone, but it does not seem too accurate.
So now I have bought two Opus BT 3400 Chargers.
They're quite good, but the voltage needs to be above 2.5 volts for it to recognize the battery as an li ion.
so I sort the batteries and then the dead ones go in a parallel homemade holder with a couple of good batteries to Pre-charge.
along with the good batteries, I also hook up the Imax b6 set to 6 amps. Since I try to revive about 10 batteries at a time, I usually get the Imax timing out at 2 hours. I find that if I use a some good Hi drain batteries out of drill packs, They don't get hot and the voltage comes up pretty quick.

But this gets the voltage up above 3 Volts so the Opus can take over.

once the batteries come out of the Opus, they go into the storage box for a while.

After about a week, I test for capacity.

I like how you catalog the batch number, It saves space like a good database should.
My spreadsheet replicates the type of pack it came from.
By doing so, I can quickly sort by capacity. or Battery pack etc.
My database skills are not so good, but my spread sheet skills get me by.
I may post my spreadsheet once I get done with capacity testing.


I am not sure what to do with the heaters yet. i may turn them into a water heater. I think I can come up with a pack cooling scheme that preheats the water going into my domestichot water heater. For now I am just segregating them.

The completely dead batteries I am holding onto for the time being. I have a feeling at some point the cobalt and lithium will have a higher scrap value than they have right now.

---

Droid126 said:

Hello all,
I was just wondering if anyone catalogs their cells?

I keep a spreadsheet of every cell I am able to test. I record things like the make, model, tested capacity, any specs I can find on data sheets, etc. I thought that by doing this over time I could find some trends, maybe see which model#'s had the best characteristics. It also does some basic calculations.

I haven't cataloged the cells that could not complete a test cycle i.eheaters, self-dischargers, physically damaged cells

I thought some of you might be interested

Here's a link to my spreadsheet

Click to expand...

Thanks for the link to your spreadsheet.

I also am cataloging the cells. Though I have not tested them all.
I am logging what the initial voltage was and then going through charging them.
I have an Imax b6 clone, but it does not seem too accurate.
So now I have bought two Opus BT 3400 Chargers.
They're quite good, but the voltage needs to be above 2.5 volts for it to recognize the battery as an li ion.
so I sort the batteries and then the dead ones go in a parallel homemade holder with a couple of good batteries to Pre-charge.
along with the good batteries, I also hook up the Imax b6 set to 6 amps. Since I try to revive about 10 batteries at a time, I usually get the Imax timing out at 2 hours. I find that if I use a some good Hi drain batteries out of drill packs, They don't get hot and the voltage comes up pretty quick.

But this gets the voltage up above 3 Volts so the Opus can take over.

once the batteries come out of the Opus, they go into the storage box for a while.

After about a week, I test for capacity.

I like how you catalog the batch number, It saves space like a good database should.
My spreadsheet replicates the type of pack it came from.
By doing so, I can quickly sort by capacity. or Battery pack etc.
My database skills are not so good, but my spread sheet skills get me by.
I may post my spreadsheet once I get done with capacity testing.


I am not sure what to do with the heaters yet. i may turn them into a water heater. I think I can come up with a pack cooling scheme that preheats the water going into my domestichot water heater. For now I am just segregating them.

The completely dead batteries I am holding onto for the time being. I have a feeling at some point the cobalt and lithium will have a higher scrap value than they have right now.