Am I doing this right ?

G

g3org3s

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Hi forum - newbie here. I have been harvesting some cells from old laptop batteries and got a decent number of cells.

I measured the voltage of these cells and they range between 0.8V up 3.8V.

I have purchased an Opus charger anddischarging at 1000mah and once the battery is empty, I would charge it at 1000mah.

I cant seem to be able tocharge at more than 1000mah. Discharging in one case was limited to 700. cells charged up to 2800mah, some 1200mah.

  1. Am I doing this right ?
  2. Should I charge with slower rate ?
  3. Next step is to monitor the voltage ? if that drops below 4.12V after charging ?

If there is a guide or video out there please link.
thanks!
 
1000mah isn't too high for fresh cells you want charged reasonably fast so you can put them back into service. Its not going to hurt older cells, but, they will probably be happier with half that, at the cost of your time and patience since the charge time doubles. For the really low voltage cells, they say you should revive them with very low current until they have recovered enough voltage to be normally charged. Either way you charge, full 1000mah, half that, or sub 100mah, keep and eye (or should I say hand) on the old cells for becoming overly warm into the hot. A little warm isn't bad.

As, for discharge, 500 mah is a little nicer on the cells and you will probably get a bit better capacity. Check out the cell discharge graphs for lithiums and you will see how voltage and time are related to the discharge amount.

I'm of course giving you very conservative advice based on the assumption you have time to charge/test and want to maximize the remaining number of cycles left. Another way they say to maximize the number of cycles is to tighten up with max charge/ discharge numbers, at the cost of capacity. I.e. charge to 4.1v instead of 4.2v you essentially double the cycles. ( source: https://batteryuniversity.com/index.php/learn/article/how_to_prolong_lithium_based_batteries)

I'm in the same boat as you and waiting for my cells to settle and see which are self discharging. I'm probably not going to remember exact voltage numbers for pass/fail, I probably figure that out relatively and sort them into voltage reading groupings. I figuring, or at least hoping, that they all drop or stay the same and the out liners will be obvious.

My charger didn't like the low voltage cells and thought they were NiCads. I pulled these aside for a "rejuv" at some later point. Some people decide these cells, obviously either self discharged or were allowed to go below acceptable limits, are not worth keeping due to damage and loss of capacity. Others say: "waste not want not" and attempt to bring these back to life and possible use, usually in a lower drain application paired with other "orphaned" cells.
 
The cells that read 0.8 volts are probably not worth saving. If you get them to charge use them in flashlights orsomething not demanding. I have 2 opus chargers and every cell I got I charge/discharge/test at 1 amp. If a cell won't operate at that amperage it goes in the flashlight box. All 18650 should handle 1 amp, if not you shouldn't use them in a pack. When you set the charge/discharge to 1 amp and the charger reduces the amperage it usually means that the opus found something wrong with the cell and has reduce amps accordingly. A good cell will always charge/discharge at 1 amp, when near full it will reduce to less then 100ma.

The opus is very limited in its ability to revive cells under 2 volts. If you plan on reviving cells get a foxnovo 4s, I revived many cells with that charger. You put the cell in and it will stop charging, remove cell and pop it back in, repeat numerous times until it revives the cell.The opus just won't charge a dead cell no matter what. But the cells I revive goes in the flashlight box, they are usually low mah or won't hold charge.
I had 50 powertool 18650 one time, they were all under 1 volt, the opus didn't charge a single one, but the foxnovo revived about 20 of them.

Once you charge to 4.20 volts, I usually check the voltage after 1 hour, it needs to be above 4.18for me. Anything lower than that I seperate for more testing. If its at 4.12 it goes in the flashlight box. You should not loose to much voltage after 1 hour. If you use a cell that can't hold voltage in a pack, you will have balancing issues. Some people wait a week and check voltage again, but I found out 1 hour is enough time for me to determine if the cell is good.

Your doing it right, stick to 1 amp so you get better results. The ones that won't charge are just bad cells that the opus won't revive. Even if you lower the amperage, it won't fix it. If you want to use those cells you need a foxnovo, once the foxnovo revives it you can put them in the opus.

foxnovo 4s is not in the same league as the opus but its cheaper, it can also capacity test 18650. Where it beats the opus is in reviving dead cells.

image_wkydjs.jpg
 
Doing it right has many interpretations and variations.
But one thing always stands out we all want to do it as fast as possible.

image_wykemu.jpg


The problem is that there are many factors in successfully harvesting used 18650 cells.
Everyone has their "preferred method" of doing it right.
Is there a right way, a wrong way, or a better way?
I do believe there is.
The first step is to learn about cell chemistry. For the sake of simplifying it I will refer to two different chemistries most common to those of us that harvest cells (specifically 18650s)from laptop and toolpacks. INR and ICR highdrain and lowdrain respectively.
These 2 chemistries have radically different criteria by which to charge and discharge them.
Example:
INR18650-15M standard charge750mA and standard discharge 1500mA this cell is meant to last an hour but deliver peak power for that hour.
ICR18650-26F standard charge 1300mA and a standard discharge of 520mA this cell was meant to last5 hours at a standard drain and would more than likely deliver 10 hours at 260mA drain.
Now these 2 examples are at the opposite sidesof the spectrum for each and most cells of either type are somewhere in the middle but it is to prove a point.

Certainly there are maximum charging and discharge parameters given for each cell such as there is a maximum RPM given for each engine. Does that mean we will keep them at max RPM all the time? No. Just as with an engine that has some miles on it we don't floor it at every stop sign just every now and then. Most of the time we are using a 10th of the engines power.
There are reasons the manufacturer of these cells put out specification sheets for each and everyone of their models and give you the charging mA numbers and discharging mA numbers by which to test the cells at.
All 18650 cells are not alike as in generically charging them all at 1000mA and discharging them at 1000mA. There is a reason most charger/testers have several different mA settings.
Lets take aCGR18650CE Panasonic(found in medical packs and laptops) for example. The Factory recommended "Standard charge rate" is 430mA at CV/CC for 8 hrs or a quick charge at 1500mA CV/CC with a 110mA cutoff at the top of the charge. The standard discharge is 430mA and the maximum continuous discharge rate is 2500mA with a 45C shutdown.
How do our OPUS, Foxnovo, LiitoKala, Zanflair etc. fit into this parameter? they don't.
So what do they provide?
They provide an acceptable average charging rate and discharging rate for a majority of the 18650 cells we use.

One thing of noteis a lower mA charge is never going to hurt your cell (it just takes longer to charge) but a higher than recommended mA charge will.

My findingwhether right wrong or indifferent is that I charge ALL my <3V (that includes 0.5Vcells, all in separate voltage batches of course, in parallel)at 50mA per cell till they hit at least 3.8V and most of the time I will let them charge at 50mA till 4.1V. You cannot hurt a cell with low mA and slow charging.
Another note is that all the cells I charge have to initially pass an IR check. This is done with the manufactures recommended method with a m? AC1 kHz4 wire kelvin resistance tester. This is manufacturer and cellspecific and varies from manufacturer to manufacturer and cell part number to cell part number.

Does it take more time sure but the results are very good and these cells are not a flash in the pan as 98% will maintain their V after 30 days and I have spot tested many of the low V recovered cellson my SKYRC at manufactures standard charge and discharge rates and most of them have stayed the same mAh as first tested and some of them actually improve very slightly on each cycle.
Does it take time yes it does but a wise old man once told me"There never enough time to do it right the first time, but always enough time to do it over".

So my suggestion is do your research, follow good guidelines, a lot of people here have great input and are very knowledgeable about this subject and most of alltake your time and do it right.This is at least a commitment for anywhere from 6 month to a year depending on the size or your packs. For me it will be ongoing but it will slow down after my 14s200p is built.

Best of luck and do it right.

Wolf
 
Wolf said:
Doing it right has many interpretations and variations.
But one thing always stands out we all want to do it as fast as possible.

image_wykemu.jpg


The problem is that there are many factors in successfully harvesting used 18650 cells.
Everyone has their "preferred method" of doing it right.
Is there a right way, a wrong way, or a better way?
I do believe there is.
The first step is to learn about cell chemistry. For the sake of simplifying it I will refer to two different chemistries most common to those of us that harvest cells (specifically 18650s)from laptop and toolpacks. INR and ICR highdrain and lowdrain respectively.
These 2 chemistries have radically different criteria by which to charge and discharge them.
Example:
INR18650-15M standard charge750mA and standard discharge 1500mA this cell is meant to last an hour but deliver peak power for that hour.
ICR18650-26F standard charge 1300mA and a standard discharge of 520mA this cell was meant to last5 hours at a standard drain and would more than likely deliver 10 hours at 260mA drain.
Now these 2 examples are at the opposite sidesof the spectrum for each and most cells of either type are somewhere in the middle but it is to prove a point.

Certainly there are maximum charging and discharge parameters given for each cell such as there is a maximum RPM given for each engine. Does that mean we will keep them at max RPM all the time? No. Just as with an engine that has some miles on it we don't floor it at every stop sign just every now and then. Most of the time we are using a 10th of the engines power.
There are reasons the manufacturer of these cells put out specification sheets for each and everyone of their models and give you the charging mA numbers and discharging mA numbers by which to test the cells at.
All 18650 cells are not alike as in generically charging them all at 1000mA and discharging them at 1000mA. There is a reason most charger/testers have several different mA settings.
Lets take aCGR18650CE Panasonic(found in medical packs and laptops) for example. The Factory recommended "Standard charge rate" is 430mA at CV/CC for 8 hrs or a quick charge at 1500mA CV/CC with a 110mA cutoff at the top of the charge. The standard discharge is 430mA and the maximum continuous discharge rate is 2500mA with a 45C shutdown.
How do our OPUS, Foxnovo, LiitoKala, Zanflair etc. fit into this parameter? they don't.
So what do they provide?
They provide an acceptable average charging rate and discharging rate for a majority of the 18650 cells we use.

One thing of noteis a lower mA charge is never going to hurt your cell (it just takes longer to charge) but a higher than recommended mA charge will.

My findingwhether right wrong or indifferent is that I charge ALL my <3V (that includes 0.5Vcells, all in separate voltage batches of course, in parallel)at 50mA per cell till they hit at least 3.8V and most of the time I will let them charge at 50mA till 4.1V. You cannot hurt a cell with low mA and slow charging.
Another note is that all the cells I charge have to initially pass an IR check. This is done with the manufactures recommended method with a m? AC1 kHz4 wire kelvin resistance tester. This is manufacturer and cellspecific and varies from manufacturer to manufacturer and cell part number to cell part number.

Does it take more time sure but the results are very good and these cells are not a flash in the pan as 98% will maintain their V after 30 days and I have spot tested many of the low V recovered cellson my SKYRC at manufactures standard charge and discharge rates and most of them have stayed the same mAh as first tested and some of them actually improve very slightly on each cycle.
Does it take time yes it does but a wise old man once told me"There never enough time to do it right the first time, but always enough time to do it over".

So my suggestion is do your research, follow good guidelines, a lot of people here have great input and are very knowledgeable about this subject and most of alltake your time and do it right.This is at least a commitment for anywhere from 6 month to a year depending on the size or your packs. For me it will be ongoing but it will slow down after my 14s200p is built.

Best of luck and do it right.

Wolf
Click to expand...

Thanks for taking the time to write this. Indeed it is very helpful. More research is needed for sure. For now I have about 100ish batteries to work with. I shall start/continue on this road! thanks and best of luck with your projct

jonyjoe505 said:
The cells that read 0.8 volts are probably not worth saving. If you get them to charge use them in flashlights orsomething not demanding. I have 2 opus chargers and every cell I got I charge/discharge/test at 1 amp. If a cell won't operate at that amperage it goes in the flashlight box. All 18650 should handle 1 amp, if not you shouldn't use them in a pack. When you set the charge/discharge to 1 amp and the charger reduces the amperage it usually means that the opus found something wrong with the cell and has reduce amps accordingly. A good cell will always charge/discharge at 1 amp, when near full it will reduce to less then 100ma.

The opus is very limited in its ability to revive cells under 2 volts. If you plan on reviving cells get a foxnovo 4s, I revived many cells with that charger. You put the cell in and it will stop charging, remove cell and pop it back in, repeat numerous times until it revives the cell.The opus just won't charge a dead cell no matter what. But the cells I revive goes in the flashlight box, they are usually low mah or won't hold charge.
I had 50 powertool 18650 one time, they were all under 1 volt, the opus didn't charge a single one, but the foxnovo revived about 20 of them.

Once you charge to 4.20 volts, I usually check the voltage after 1 hour, it needs to be above 4.18for me. Anything lower than that I seperate for more testing. If its at 4.12 it goes in the flashlight box. You should not loose to much voltage after 1 hour. If you use a cell that can't hold voltage in a pack, you will have balancing issues. Some people wait a week and check voltage again, but I found out 1 hour is enough time for me to determine if the cell is good.

Your doing it right, stick to 1 amp so you get better results. The ones that won't charge are just bad cells that the opus won't revive. Even if you lower the amperage, it won't fix it. If you want to use those cells you need a foxnovo, once the foxnovo revives it you can put them in the opus.

foxnovo 4s is not in the same league as the opus but its cheaper, it can also capacity test 18650. Where it beats the opus is in reviving dead cells.

image_wkydjs.jpg
Click to expand...

Thanks for the time and writing this! it does indeed help. i will stick to the opus for now and see what kind of cells I will get in the future
good luck with your project
 
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