Sanyo UR18650AA red, discharge info?

[italianuser]

I received the cells from EnergyCells, cells 90% of capacity. Very bad shopping experience for the total lack of customer service BUT... the cells arrived, they shipped a few hours before I was ready to cancel order. And the cells were very well packaged, looked real good and how @Wolf teaches they were individually labelled. Seems great, seems an excellent product. It's a real pity that Tim doesn't manage customers, really, man... I already spoke my mind about this in another thread ok, lets go to the cells.



Now my question is about the Sanyos... I ordered 200 Sanyos UR18650AA and 200 Samsung 22P.

Of the first three random Sanyos I tested, two had SD problems so I was quite worried. The Samsung cells are perfect, good IR, good capacity, low SD. So now I'm testing another 12 Sanyos, I have the results for the first 6, and I wanted to know if the SD I'm measuring is normal because it's double respect to Samsung cells:

Cell #	Capacity (Liitokala 500)	V (after 2 hours)	V (after 4 hours)	V diff
1	2242	4.2016	4.1945	0.0071
2	2271	4.2043	4.1956	0.0087
3	2252	4.1891	4.1807	0.0084
4	2295	4.2088	4.1982	0.0106
5	2248	4.2027	4.1922	0.0105
6	2215	4.1842	4.1733	0.0109

Maybe I'm just paranoid because the first two cells were bad... Is it normal (not that I'm addicted and paranoid, but that Sanyo are discharging twice as fast than Samsung lol) ?

 

[italianuser]

I think I have an answer. Sanyo cells do actually discharge faster, a lot faster, than Samsung cells during the first hours. Now, after 24 hours, all cells are nicely settling around 4.18V. I was very concerned because the first cells I tested were bad (incredible coincidence). Ok, @Wolf I'm getting to know my cells, thanks bro

I discovered something else during this test... One of my three Liitokalas charges less than the others... on average about 0.015V less, I'd never noted that until now. Don't have a solution for this, I could open it and have a look, I suppose output is regulated by a resistor network as some point...

 

[ziporah]

I ordered 500 of those Samsung cells. Mine don’t sit in the 90% range. About 40% is below 90%. I did test the cells between 4.2 and 3V. I have measured the IR for all of them and 30/500 are above 35m. In the end I kept 444 of the 500 cells resulting in 3153 wh use full capacity. The rest is discarded. The discarded high IR I’m using for a small 12v ups for my raspberry pi cluster. The rest is recycle bin. I was planning on getting some more but it appears somebody has been shopping their store empty. I don’t like the mixed boxes they offer as you don’t know the real capacity vs left capacity.

 

[italianuser]

Yes, I wouldn't buy from them any more. I didn't try many of the Samsung cells yet, I'm concentrating on the Sanyo ones. Of the 18 Samsung ICR18650-22P I tested (random picks), they all were over 90% of the nominal capacity 2150mAh (minimum 1938, maximum 2062). Consider that datasheet (here) states that IR for new cells is <=35mOhm:





I'll surely share the outcome of the complete test. These cells they sent look ****ing great.

These are the Samsung cells:



EDIT: well, yes, reading your post again I think you knew standard IR for new cells LOL

 

[ziporah]

looking at the labels on your batteries, they seem to be tested with their old tester.
I have a batch that has new stickers on them, they also show the IR of the battery, measured during the cycle. I didn't keep them apart in my tests, so I'm not sure these are better capacity rated or not.
I'm testing all cells with a ZB206, charging with TP4056, resting 10+ days, capacity test down to 3V, rest 10 days, charge to full , measure IR YR1030 and depending on IR + Cap store for building, store for ups or small battery use or discard.
I will test a batch of 12 (that's how many ZB206 units I have) up to 2.75, to see how the results are compared to the label on the battery.
I can share the results as well, I've put them all in a google sheet