Wow vidramon, that friend of yours is a real pro! A real pro-bungler, I mean.
Cell balancing is cruciaI for battery pack assemblage. Assuming the cells are factory brand new, probably the easiest way to do this is to interconnect all of the cells in parallel and optionally apply a brief charge to speed up things:
With regards to the solder job, use adequate interconnecting wire gauge, apply aggressive flux and preferably use low temp solders. May do with Sn63Pb37 but you need proper skill and a powerful iron, and I'd also add a wet rag to immediately cool down the battery terminals upon solder pooling, heat source removal and solidification.
A low temp solder like Rose's metal plus Goot Super Soldering Flux is a wonderful formula.
Cheers ^:)
Originally posted on Wed, 04/12/2017 - 03:20; lil fixup.
He is not my friend, just a guy that have store with cameras, he recording a weddings, birthdays, etc and have many cameras.
He gets 18650 from me, and full story goes in this way.
Get last time 3x vtc5 and do not use them about two months, when I give him a batteries I check them and all was about 3.5 - 3.7 V, new unused, never charged. These days he try to replace in one battery pack and this happens. He told me that he allegedly try to charge batteries before soldering it into pack and that one of them won’t go more from 3.7 V, other was 0…
I was thinking if you try them before soldering and see that one is 0, and other won’t charge, why the hell you put them in the battery pack and solder it ??? What you expected that battery will be raised from the hell ?
So I doubt in that I think that he get the problems after soldering it and that he destroy it in that process or that charger in battery pack messed up things. As far as I know battery can’t be drained to 0 from standing 2 months in proper conditions. Also he is not messed up with connections, since this is not first time that he do this, as someone say that inside is some plastic between chemistry and I see a lot of solder on + and -, I assume that he melt that plastic or whatever and destroy it… Does someone experienced that new battery will bloat from standing ? I would not say.
And third battery that was ok for sure destroy a charger since one is 0 and one won’t go more than 3.7 V, all current go to third and boost it to 4.5 V. So I ask here for experiences and what may cause this damages that I can see if my prediction is in right way…
All of this sounds messy. How is it possible for a cell to not go above 3.7V? Maybe he set it on a LiFePO4 charger?
With cell voltages so dissimilar, just trying to set them in parallel would result in witnessing severe sparking, crazy current flow and overheating. For the “0V” cell to not start sinking current from the other cells like crazy, it'd have to be… a brick. Nonsensical. :facepalm:
