Put a slight drop of Goot Super Soldering Flux over the cell's flat top, attach a clean disc shaped magnet to the top of the cell, centered; place a blob of solid Si50Pb32Sn18 above it, and then apply a preferably hot (300+°C) soldering iron tip on top with a gentle and slow movement downwards the magnet top.
The Rose's Metal pools instantly because it melts at a lower temperature than the liquid flux, with evaporates just after this, creating a very nice joint.
I got the 4 Black LiitoKala 26650 5000mAh cells yesterday. Soldered a bump on the positives for series use, will be doing some careful initial testing as I can (still under Dr.s orders and chillin)
They look good, seem to work well, but I haven’t taken comparison measurements yet…
-All 4 arrived at exactly 3.8V
-Cycle test shows <0.2% variation in charge/discharge capacity, which means perfect battery health, most likely produced very recently.
-Capacity sightly lower than 1st gen blue wrap, which scored ~5,300mAh
Why do people tell the arrival voltage? It’s supposed to be about 3.8v as it’s required by shipping laws, etc…
Do people tell this just to let others know that they are meeting the shipping requirements? It seems like useless information. Am I missing something?
Perhaps the arrival voltage could show if a cell is old and in rested condition has lost some voltage? Or just as a reference point? Or truth in disclosure, stating everything the charge cycle showed them?
Sometimes I notice that when charging em up the first time, usually I don’t pay it a lot of mind. As long as all 4 are very similar that’s all I care to see. So maybe in this way you know the 4 cells are matched, not one old one from 2 years ago and 3 new ones. So yeah, it could be pretty relevant if you’re using all 4 cells in one light (which I am, these)
I might be wrong on that. It was either 3.8v for air travel so it’s mostly discharged or 3.8v might be the best voltage to store a cell at long term. Either way the battery companies always seem to send them out at that voltage.
Mentioning the arrive voltage is some sort of a tradition, it has always been this way. I think they do a couple cycles to the cell and set the end voltage to 3.7 or 3.8V, and if some cell arrives differently it means a bad cell or inconsistency in the QC process. I do like to see perfectly matched cells on arrival and after discharge cycles, probably that information can help others too.
BTW it is extremely easy to add a solder blob top to the cells, just sightly sand the top, use your iron on the highest setting and use a low melt solder. It is way more reliable than using the spacer and reduces resistance.
Aaah, you mean metal spillings, shadockan? None. :-)
I have a couple of LiitoKalas from a dismantled, work in progress powerbank, but it doesn't looks very fine on these as they only have a “dismantled” wire solder. ;-)
I have to solderblob a TrustFire IMR14500 (red-gold) for a friend soon, and he already has one of those done plus an NCR18650B. I'll recall for a nice picture of this to be shot.
Just tested between my blue and black LiitoKala 26650’s in a modified Convoy L6 (FET driver, XHP-70.2)….
Blue showed me 16.48A and did 9,108 in the light box
Black showed me 18.16A and did 9,280.5 in the light box.
192 lumens more at the sacrifice of 1.68A more draw, seems odd, but I’ve seen it where it flips, the one that has highest current doesn’t necessarily produce the most lumens.