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Paralleling cells before Self discharge and capacity testing
#11
Why not charge them paralel? If your psu is up to the job!





Cool
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#12
Nice little parallel contraption. I do a fair share of parallel charging myself, or to allow cells to equalize with each other before putting them in series.

I do like parallel charging them removing them and allowing them to rest. I just mark the box what voltage they all came off at and its interesting to see how some drift from others. The self discharges become a little more obvious using that method for me.
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#13
I parallel charge 36 at time before sorting into capacity. Much easier to see self dischargers when they all start at exactly the same voltage.
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#14
@Oz18650 to maximum means to the official 4.2V.
If a cell cannot reach that charge level, or overheats a lot while doing so, it's dying anyway and should be excluded from the top lots.
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#15


or 100. Cool
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#16
(11-12-2019, 08:19 AM)Overmind Wrote: @Oz18650 to maximum means to the official 4.2V.

This is kind of the point of this whole thread.
The very commonly used TP4056 and/or clones do not charge to 4.2 exactly.
They are a bit all over the place.
You can not just charge 10 cells uaing 10 tp4056 boards and then put them away knowing that they are all at 4.2v
Some will be over and some will be under, so when checking later for self discharge, you don't know what they started at without binning based on start voltage, or recording starting voiltages some other way.
I was suggesting balancing sets of charged cells so they all start waiting for SD testing at the same voltage.
Parallel charging could alao work.
Has anyone checked how consistent the opus charge voltage is?
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#17
Opus is basically the same. Question is what DO you gain from running 0.01v 1% accurazy before SD?

I bet nothing. Smile

For instance the capacity is also all over the place. As Long as its randomized i bet IF you just guessd the Numbers and say lets have Them above 4.1v it should be ok. With that Said i have of course checked so all My opused atleast Charge to 4.1ish
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#18
(11-12-2019, 09:38 PM)Oz18650 Wrote:
(11-12-2019, 08:19 AM)Overmind Wrote: @Oz18650 to maximum means to the official 4.2V.

This is kind of the point of this whole thread.
The very commonly used TP4056 and/or clones do not charge to 4.2 exactly.
They are a bit all over the place.
You can not just charge 10 cells uaing 10 tp4056 boards and then put them away knowing that they are all at 4.2v
Some will be over and some will be under, so when checking later for self discharge, you don't know what they started at without binning based on start voltage, or recording starting voiltages some other way.
I was suggesting balancing sets of charged cells so they all start waiting for SD testing at the same voltage.
Parallel charging could alao work.
Has anyone checked how consistent the opus charge voltage is?
You don't need to charge to exact value. charge up to 4.1+ as most TPs actually do and then charge the remaining with the actual tester.
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#19
Use a buck converter.
Or order ONE batch + 10% of those tp/tc,s and sort them with a high uf (F) capacitor (to be quick)to match them and to make sure they all end at the same voltige...
I loaded them per 100 at the same time at the same speed to the same voltige in one go.
That experiment was better than 30 tp/tc's sorted out.

4 x https://www.aliexpress.com/item/32872607...4c4dJaFzQX
Connected them to my Philips psu's.
Someone like me can not have enough of them.
max they will do is 11,25A ish

https://www.aliexpress.com/item/32945969...4c4dykVCjt
Probes are very easy to solder.
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