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cells charging with 18650 charger
#1
hi  all i dont know my last fil was closed. I would like to know if I can charge my cells with a simple 18650 charger before testing them in the opus charger? just to save time, thank you.
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#2
Yes you can but with same current the time it takes is the same Wink
NOTE! My links supplied in this message may be affiliated with Ebay and by clicking on them you agree on the terms.
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
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#3
I think what stiplanet is saying instead of a complete charge-discharge- charge cycle. He wants to charge+2.5v cells in a 18650 charger while he is testing other 18650's in the Opus.

later floyd
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#4
Yes, you can certainly dedicate your analyzing chargers to the discharges and use other (cheaper) chargers to do the charge.

But for the capacity results to be comparable try to use chargers that terminate with the same voltage and same termination current (else you may end up comparing apples vs. oranges since one charger may do a much fuller charge than the others).

See e.g. Battery charge termination test to get an idea of how much effect on capacity is caused by variations in those two parameters. 

For rough first level sorting such variations may not matter much, unless you have the bad luck of getting some chargers with extreme voltage calibration differences and/or different termination currents, e.g. if one terminates at 4.25V,100mA and another at 4.15V,200mA, where the linked graphs show that the first charger may charge an NL166 12% more, and an PA18650 7% more (generally the differences will be higher for unhealthier/smaller cells due to their higher IR).
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#5
thank you all for your advice, I already have 5 opus BT310 c. and I find the process a bit slow, I have 3000 cells to test, either I increase the number of opus charger? or if you can advise me another charger .
 thanks best regards.
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#6
(08-19-2020, 03:22 PM)stiplanet Wrote: thank you all for your advice, I already have 5 opus BT310 c. and I find the process a bit slow, I have 3000 cells to test, either I increase the number of opus charger? or if you can advise me another charger .
 thanks best regards.
5 OPUS x 4 cells = at least 20/day = 150days.   I only have 3 OPUSs and am nearing 10,000 cells.   Agree that 10 or 20 OPUSs will shorten the thru-put Smile

One thing I do is go for the same cell type per battery (14s100p) so I know the cells are compatible chemistry up front and if they are from the same 'source', they will likely be in similar testing range in terms of IR and mah.     This let's me test for 4 weeks (to get a leading self-discharge window) and then start building packs in parallel with the rest of the testing.   Also build the shelves/cables etc.    This helps shorten the overall process so that battery construction is finished 4 weeks after the testing is complete.
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#7
Dont mix testers. Use one tester so you dont have to worry that much about the results.

I have 10 opus. Thats 80 cells per day.... You should be able to do 40 per day easy Wink
NOTE! My links supplied in this message may be affiliated with Ebay and by clicking on them you agree on the terms.
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
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#8
I do so too, pre-charge the cells at cheap chargers while testing another lot of already fully charged cells in some Liito Kala 


I really like the XTar VC8 8-slot charger (middle, left), but they are not really cheap and handle a maximum of 300mA per slot, so I added some super-cheap chinese chargers (top row)

10 independent slots each at 0,6A cost round about 10 - 11 USD incl. shipping


Phomax 10 slot LiIon charger (the same from brand GTF)

 



quality isn't the best and I had already three defective charging pcbs,
but got three new chargers send out, took the bad pcbs out, replaced them with good ones and now have too functional chargers = 20 slots extra.
Should not be your first-use charging device but for fast bulk charging it's perfect - for me.
Oh, and they can do 0V reactivating as I tested, that's the first picture
OffGridInTheCity likes this post
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#9
You can quickly weed out bad cells by testing for -
- IR (internal resistance)
- cells under 1V (recycle these, not recommended to use for powerwalls, maybe ok for torches, etc)
before charging.
Running off solar, DIY & electronics fan :-)
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