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Korishan

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Well, I've started going around to the various computer shops, battery replacement shops, and even Lowe's (haven't made it to Homer yet). So far, batting 1000. Ugh, everyone is turning me down.

However, I do know a guy who is in co-op business with the local storage unit garage sale that has a lot of units at the place where I house my products that I deliver. Well, tomorrow, he's going up to north florida to meet with a buddy of his that does computer work. And, he may come back with like 50+lbs of laptop batteries for me :D

Those'll be my first batch of batteries to start working on if everything works out.

Still waiting on my 4056 chargers (Estimated deliveryFri, Jan 27 - Fri, Feb 24)andNitecore D4 (Estimated delivery Wed, Jan 11 - Wed, Mar 01)charger to show up. Stupid chinese mail. The 4056's should be here any moment now, I hope.

Will keep ya posted as to status and such.
 

Aspendell

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Jan 31, 2017
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Kor,
I'm not sure what all you tried, so forgive me if this is an old idea. Have you tried offering them a dollar or 2 for each battery pack. When I started looking most people couldn't find the time to even consider it until I suggested they could make some free money ;)
I walked in a small computer shop and lead with saying I had $50 to spend to save them a trip to the dump. That made all the difference. I walked out with 60 laptop batteries, 10 of which were 9-12cells.

Also try anywhere that uses rechargeable batteries daily. Like security companies, or service companies that use handheld radios/scanners and rechargeable power tools. Some of them just order 10 new battery packs a month and have boxes full of old ones.

Think outside the box to get them into yours ::wink::
 

Korishan

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Yeah, I did. One shop actually asked what the going rate was. But they all have 'contracts' with the recycler companies. Whomever they are.

The one Lowe's (we have 2 here) I asked at, the guy I talked to I have no idea who he talked to on the phone to ask. I'm gonna go back and talk with one of the managers I know from years back when I worked there. He wasn't there today.

Hahah, outside the box, I like that one :) Will definitely keep looking around.
 

Rerouter

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Jan 1, 2017
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security companies and auto doors are great if you need hundreds of small 3 year old lead acid batteries,

for 18650's your probably going to want to chase down construction firms who burn through portable batteries.
 

FireFrog

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Jan 22, 2017
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Careful with the nightcore d4, I had a fake one and the screeen said it charged to 4.2 but stopped at 3.15-3.18

So if you plan to set them aside to self discharge and test voltage later just make sure you test them after a charge to get a good reading or you may set aside cells thinking they lost more than 0.5 of a volt when they are good cells
 

Korishan

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Careful with the nightcore d4, I had a fake one and the screeen said it charged to 4.2 but stopped at 3.15-3.18

So if you plan to set them aside to self discharge and test voltage later just make sure you test them after a charge to get a good reading or you may set aside cells thinking they lost more than 0.5 of a volt when they are good cells


That's good to know, thanks. I'll keep that in mind when I get it and will definitely do a secondary voltage test afterwards.

I had actually ordered the D4 before I saw a lot of the build-ur-own chargers/dischargers. So, I'll probly only use it for a short time because I am a firm believer in trying to do as much as you can yourself and getting as much control over a project as possible. I don't like unknown fully automatic systems where I don't really know what's going on.
 

FireFrog

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Jan 22, 2017
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Grab some 4056 chargers and a old power supply and you'll be golden ?


Sorry meant to put a smiley face not a question mark
 

Korishan

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hehhe :p

Yeah, pretty much, to start with, at least. Then I'll work on more detailed units later. Ones that will charger, discharge, measure resistance, recharge (possibly even repeat x times)
 

FireFrog

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Jan 22, 2017
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http://www.ebay.com/itm/222375356318?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT

i ordered these and some holders


Oh just thought I'd test my 4056 modules
So pulled a finished cell and another finished charging cell
Both had different voltages so even then it's a manufacturer quality thing
I think it may be better to charge and mark finished voltage or something to determine self discharge value


Thinking about these values now
If I have a cell at 4.2v and let it self discharge
Then discharge it to 3v then charge to 4.1v I wonder the time it takes to self discharge is different due to a lower SOC

I'm wanting to test this
One week for one cell to sit after a charge to 4.2v then take down remaining voltage
Then charge it back to 4.1v then take down voltage I wonder if the percentage of loss remains the same
 

Aspendell

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Jan 31, 2017
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FireFrog said:
http://www.ebay.com/itm/222375356318?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT

i ordered these and some holders


Oh just thought I'd test my 4056 modules
So pulled a finished cell and another finished charging cell
Both had different voltages so even then it's a manufacturer quality thing
I think it may be better to charge and mark finished voltage or something to determine self discharge value


Thinking about these values now
If I have a cell at 4.2v and let it self discharge
Then discharge it to 3v then charge to 4.1v I wonder the time it takes to self discharge is different due to a lower SOC

I'm wanting to test this
One week for one cell to sit after a charge to 4.2v then take down remaining voltage
Then charge it back to 4.1v then take down voltage I wonder if the percentage of loss remains the same




Sounds like Korshan is about where I am in the hobby atm. We don't have nearly everything we'd like yet, but trying to get by with what we have and learn in the mean time from the rest of y'all.

As has been repeated over and over, its not about precision when it comes to capacity tests so much as accuracy. So the most important thing in testing is that your method is repeatable with results within 5% or so of previous tests, strictly so you can compare cells for grouping in packs. If you have a commercial tester that varies 15% from test to test on the same cell, I'd find another method.
As I mentioned in another thread, I tested 3 widely varying cells 3X on my setup and they came up within less than 2 mah of each other each time. That is .002 Amp hours out of 1200 - 3300mah. That is good enough for me to compare no matter how imprecise it may be.

Take this with a grain of salt as I don't have any personal empirical evidence. However many have tested the 4056 charging modules that most are using (Like Julian and Adam). They have a fairly wide divergence of cutoff voltage, like +- .15v, and they don't tend to hold voltage once you initially hit that level in charging. Sure they will turn the charge back on once the cell drops below 4.05v or so if you leave them in there long enough.
But a cell that is initially charged at 1 amp to even 4.2v still has 15% uncharged capacity remaining. And for me at least, up to 300mv variation between modules for charging is too much, for testing purposes at least.

I have a theory that most that are having serious issues with the Sanyos are using either a commercial charger or 4056 modules. They just can't top off the capacity or even come close on a marginal cell.

I do have a couple 18650 power packs that use the 4056 topology for charging and delivery. And often they won't charge much past the 3.2v or so that others are reporting, with initially undercharged cells.

So for me so far, its DC-DC converters. Set the exact voltage and current to the nearest mv or ma. :blush:
 

CUDAcores89

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Dec 30, 2016
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I know this is the way it is in michigan, but you may also want to check out your local scrap metal yard. Some yards take laptop batteries these days and my local one sells them to me for $1.5 a pound.
Also, if any computer repair store turns your down because they have "contracts" with others who buy their laptop batteries (after of course offering to pay for them) ask them who they are. If they do not tell you keep asking. Keep doing this until the manager asks you to leave.

Because if I go to a place that won't give me laptop batteries, I have absolutely nothing to lose. I might as well poke, prod and pester them until I find out their source. It's not like I am ever going to go back to the place I visited for any other reason so it's not like I have to worry about tarnishing a reputation. So if you are having this littlesuccess, it's time to start being nosy.

Then once you found out their source, go to that source and offer to buy them. If they sell the laptop batteries to somebody else and they refuse to sell to you, repeat the steps above to find out who it is.

Continue repeating these steps until you are able to secure a good source of laptop batteries.
 

Korishan

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Perhaps, but pestering isn't in my nature ;)

I've tried the local scrap/recycling, but they said that once it hits their yard, it becomes county property and they can't/won't sell it after that. *grumble*

Still looking around, though. We have plenty of construction sites around here, so will start asking the foremen if I can buy the old packs off them.
 

Korishan

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Well, I got my first pack. Came from a 'dead' 18V drill battery. The guy said it wouldn't hold a charge. But I did a test on all the cells, and I was surprised for a "dead" battery pack.

The over all charge was 19.15. Each cell came to be 3.83, except one at 3.81. Wonder why he was having troubles with it.

They are "se us18650vt c111vpg200". I'm guessing they are Sony's, correct?

I did a quick test to checkthe status of the cells. I know it's not the 'proper' way to test them, but I figure it's a good quick check.


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Aspendell

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Jan 31, 2017
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Awesome Korishan! Big Grats!

There was a guy in another thread asking where to get 18650s. I was gonna tell him to just talk to you as I figure you should be the forums foremost expert here in another week or so and even have plenty to give away!

If those are the green ones I'm thinking of, yes Sony's. All mine came in 1600-2200mah. Of course that all depends on charging and testing method. Since you have time on your first pack, I suggest charging them to 4.2v and hold them there for 30mins+ then let them sit idle for 2hrs and check voltage again. Keep recharging to 4.2 until they drop less than 0.02v after 2 hrs. Then capacity test them.

~Cheers~
 

Korishan

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...figure you should be the forums foremost expert here in another week or so and even have plenty to give away!

LOL Riiight :p we'll see how things go first.

I actually just posted in the Wanted forum ;)


Anyone have feedback on those preliminary test results? I don't have all the rest of my gear to do a full test, just yet. And I guess I should of asked, did I do that test right by checking voltage with a load. Also, how could I do a resistive test of the cells?
 

Aspendell

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Well like I've posted before, its just as likely that the contoller board was bad as any bad cells. So the odds are good that every single cell is fine minus a few percent capacity since new. I never ever go by the initial voltage when i open a pack.

Not much you can do until u have a way to charge them and test them. Go pull a headlight out of the wife's car and connect the 4 cells in series to it and go out and impress the neighbors with your new found power :huh:
 

Sean

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Korishan said:
...figure you should be the forums foremost expert here in another week or so and even have plenty to give away!

LOL Riiight :p we'll see how things go first.

I actually just posted in the Wanted forum ;)


Anyone have feedback on those preliminary test results? I don't have all the rest of my gear to do a full test, just yet. And I guess I should of asked, did I do that test right by checking voltage with a load. Also, how could I do a resistive test of the cells?

What value was that resistor ?

To get capacity values that you can directly relate to those quoted by others here you need to aim for a discharge current of close to 1 amp and monitor the voltage drop against time, a good usable cell, with a 1A load will sit at around about 3.7v for a couple of hours- one of those testers shown in the heading will do this automatically. If you see a voltage drop from resting (hopefully above 4v) to below 3.5v within less than an hour (or less) with a 1A load conneced the capacity of that cell is very limited.

You don't need to keep charging to 4.2v over and over again - just do it once and leave the cells for a week, the amount of voltage drop over a period is related to their internal resistance - you want minimal voltage drop over time.


Aspendell said:
I suggest charging them to 4.2v and hold them there for 30mins+ then let them sit idle for 2hrs and check voltage again. Keep recharging to 4.2 until they drop less than 0.02v after 2 hrs. Then capacity test them.

Could you explain why you have suggested this please ?
 

station240

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Oct 9, 2016
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Aspendell said:
I suggest charging them to 4.2v and hold them there for 30mins+ then let them sit idle for 2hrs and check voltage again. Keep recharging to 4.2 until they drop less than 0.02v after 2 hrs.

Lithium Ion Batteries don't work like that, you cannot blindly trickle charge them.
Doing so damages the cells in a process called "lithium plating".
Honestly just let the proper lithium ion chargers (Imax B6, TP4056 etc) charge the cells, they know how to safely do it.

I probably should do a write up on how the electronics charges Lithium Ion cells, but am busy with a backlog of soldering projects.
It's not time based, but current and voltage based.
 

Korishan

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I'm gonna hafta go with Sean and station240 on the charging methods. I've watched many-a-video show charging methods and a few about what happens to lithium when charged improperly (with dissection). I'd like to keep these cells life as long as possible.


I do have TP4056's on order. I ordered 20 units; they should be arriving any day now (unless I got jipped). Now I think I need to get a good power supply. I do have several old computer PS's laying around I could maybe re-purpose.
 
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