Beginners Guide to Processing 18650 Cells | Cell Database

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Darmok's Power Wall build
(05-03-2017, 01:32 AM)Korishan Wrote: Yes, some will go into furnace mode. Odd thing is, some of them, once they have cooled off over a few days and settled, you can drain them a little and put them back in the charger and they act normal from then on.

However, if  you use those cell, I'd recommend you mark them and put them in an easy to get to place in case of failure. Those cells would probably be one of the main reasons for fusing each cell.

I actually had one where it was making an odd smell cuz it was so hot. That was the only reason I knew it was hot for I was in the living room when I smelled it. After that, I got a thermal gun so I could monitor them a little closer.

Do you have a recommendation on a good thermal gun? I am still working on my first pack... not sure which is worse... colonoscopy or 18650 battery screening!

I just bought a cheapo from Harbor Freight. They aren't really that expensive, about $15. Now, the HF versions are probably in there because the laser pointer isn't properly centered. That's why it's at a discount in HF. I haven't taken mine apart to see if I can adjust it and make it more accurate.

The laser doesn't do the measuring. It's just there to know where you are pointing at. If you take the gun and place it "on" the packs/cells/etc, then you will get a really accurate reading. The thermal sensor is just giving an average of the center point. As you move away from the object, the area the sensor is picking up is larger. This is important when you are charging 4 cells in a holder that's only 1/4" apart. If you measure the 2nd or 3rd cell, you're going to pick up the heat from the adjacent cells and get an average. Placing the gun right on the cells gets rid of all that.

Btw, the 'brand' on the gun I have is Cen-Tek. But, I think that's just a rebranding of one of the ones you can get from the auto-parts stores as they are similar in shape, design, function, and display; as well as the sensor type.
I believe that's the same with the inverters that are branded as Cen-Tek. Though, they are still expensive.
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Small update I have arranged all my cells into their 140 cell count packs and am doing a final voltage test looking for suspect cells. So far ive tested 410 cells and have found one cell totaly dead and 2 that were suspect (voltage dropped too far more than .30v). That's 5 months since they were tested and binned into the bucket for pack construction.
Testing 2200 cells with a multimeter is a pain in the ass. Does anyone have a quick method? My current method is using a cell holder wired to meter leads.

Better to go through another round of tests than having ordinary cells pull packs down or cause more drama. Finding suspect and a dead cell vindicate it.
Korishan likes this post
(05-02-2017, 07:59 AM)Darmok Wrote: Hi all,
Please see below details of my system and what I am doing. I am keen for any feedback and input, I appreciate the interest shown.
I have a SMA 5000TL-20 inverter and 6kW of panels on the house roof. I export 40% of what generate to the grid and get a small cheque from the retailer.
Where I am it is not in my favour to yet have the power wall connected to my house . I currently get a good feed in tariff (48 cents). The feed in scheme is a local state one and has been running for 8 years. It will run out in 2.
A requirement of that agreement i have with my electricity retailer is that i have no batteries connected to that system. Obvious reason you could milk the system; charge at night at 28c and export at day for 48c. Utility and retailers here in Western Australia are still yet to get their shit together and offer attractive peak and off peak incentives.

So instead of waiting I am building a standalone system in my workshop. which will hopefully run a 1600w pool pump, workshop socket outlets and LED lights.

My process;
When I get batteries they come as laptop batteries. I get 1-3 tubs of them. I then sort packs into manufacturer then model of the batt then do the high capacity ones first, ie above 50 Whr per laptop battery pack. Saves a hell load of time only processing batts with the higher capacity first and importantly of the same construction. When you learn how to get into a pack and extract the cells its good to stay in that mode till you've done all those pack types.
 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 in each pack better than 2300 mAh.  I am going to progressively make these cells bigger when i process more cells.  Anyone see any issues extending the packs longer than 25 cells long? 30 or 40?

To get to 15 x packs of 100 has taken 4 months of processing.
Im very lucky that i have gotten volume battery packs to be able to do this. Does depend what volume of packs you are able to source.

My testing methodology has changed over time. At first I was testing voltage of every cell and then binning based on voltage. I have since stopped this and bin based on manufacturer and rated capacity. I then test in 6 x Opus charger/testers. Then bin for capacity.

I have graded tested cells into bins as follows;
>2300 went into the packs. Best i had was 3200mAh cells.

What I've found (going from memory) is;
Panasonic Grey 3000
Samsung Light blue 2800
Samsung Pink 2600
Sony Red (light blue ring 2600)
Sony Green G7 2550
Newer Sony Orange 2500
Panasonic purple 2500
Samsung blue 2400

Cells with rated capacity less than 2300 go into a bins sorted by manufacturer 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 version 1.0 performs constructed with only cells greater than 2300 mAh cells.

I am yet to decide on the Inverter and other hardware. I am keen to hear thoughts from people.
Early options are ;


PIP 4048

Battery pack mounts yet to be decided.

Pictures to follow.

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I am so freaking jealous..... I prey for grays before opening a pack, but they are typically green or red.
I was bloody lucky to get the Greys. I had enough to do the perimeter on the 120 size packs x 14, but when i went to 140 cell packs i had to cheat and skimp on the back.
Regarding greens and Reds I did have some that were right up there with the Greys they were Green G7 cells from memory.
Best Reds were the ones with light blue rings.

While doing my final voltage checks on the last 2100 cells. I am starting to finalise mount ideas. Packs now being 140 cells long i need a custom mount rather than Peters. I am thinking vertical sections of parallel electrical cable tray with the packs mounted so they can be removed reasonably easy. Although I don't envisage pulling packs every week. Cable tray provides good heat sink, plenty of fixings for cable (oddly enough) tray walls can be used to mount any separators (cement boarding) to protect parallel packs from each other in a failure. Plus it will look the part. I will see if i can find some images of what i am talking about. Something like this.
Just scored a full size server rack with built in ventilation fans. Going to explore utilising this. Photos to follow.

In other news I've Soldered up one 140p pack. I'm still deciding on how the ends will be finished off. Didn't go too bad. The learning improvement as you go is noticeable. Anybody who needs to get they're head round soldering, watch Daromers soldering video. Important points worth noting:
get a 150 minimum wattage iron.
and get into a rhythm as Daromer advises counting in your head for contact time.
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After much chasing and phone calls I have another batch of laptop batteries to process.
Does anyone have an idea for a fair and reasonable price for both seller and buyer for excess collected packs? Would $2 a pack be reasonable? Considering all the running round and time spent?
Korishan likes this post
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Learning Soldering
2146 likes this post
Nice work!

I have payed up to 2USD per pack here but then i know that 90% or around is good!
If its totally random i max pay 1USD and only for larger batches of atleast 20+ packs.
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Very nice solder beads Smile I hope mine look like that when I start putting the packs together.

Altho, my cells won't be soldered, but the other stuff will be Wink
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
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Certified 18650 Cell Reclamation Technician

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