Puzzle. I’ve gotten a wrong item from a certain Chinese site that I won’t bother to name
(well, it starts with D, ends with X, and has 2 letters)
It was supposed to be a little battery box meant to take a single 18650 cell.
Twice. When I got the wrong thing and let them know, they offered to refund, or resend, the thing.
Silly me, I said, oh, just send me the right thing, I’m in no hurry.
So they sent me the wrong thing again.
Got the right SKU number tag on the bag, but it contained
— 2 plastic shell pieces
— one plastic inside piece
— one little charger board
No springs, no wires, nothing at all to actually hold the 18650 cells and conduct electricity between them and the charger board.
Oops.
So — anyone recognize these boards? I’m not sure if there’s any (safe) use for them or if they’re electronics recycling.
above should be 25 percent size inline, but not showing up; below are links
Just solder some 22ga wire to the top and bottom of the battery (remember to scuff it before you try to solder and keep soldering iron on bottom as short as possible), shoe horn in the plastic case and voila
If you look close at the thing you ordered…there ain’t springs in those DIY kits
That board doesn’t look like one of those single 18650 boost modules though
What I ordered was not what I got (and I haven’t found what I got on their website anywhere)
What I ordered was SKU 312793 — different charger board that looks like it includes the positive contact, and as they show a wire and spring contact to reach the other end — and a box sizedfor a single cell.
The two bags I’ve rec’d have that SKU number on the label, but both had the same wrong contents, — a different board, shown in my pictures.
And the bag didn’t come with any metal parts to conduct electricity from the batteries at all, and the shell sized to hold 2 cells, different outside shape; similar, likely from the same maker, gray and white — but nope, not a thing. Just part of a thing.
Stuff happens. I’m just wondering if anyone recognizes the charger boards I got here.
(I see B+ and B- but I don’t know what battery configuration they’re expecting to be connected to; all I can tell is the case is sized for 2x 18650s.
But serial or parallel?
I’m, um, old and conservative I suppose, I’m not going to try soldering to a li-ion cell, even though I feel lucky most of the time (grin).
I know the plastic membrane inside li-ions is heat sensitive. I can attach a battery holder to the thing — but since I don’t recognize the board, I’m hoping someone might.
ps, here’s the bag with contents, maybe someone will recognize what I got?
— the SKU label is on the back side, you can see the edge of it.
Inside —that charger board, two cream-white plastic shell pieces
(POWER BANK printed on the outside of one, the other
“Capacity: 5600 mAh, 3.7V. Input: DC5V 1A(MAX)”
Nothing unexpected about that.
and one gray plastic piece that the white pieces and charger board would snap into
(I’d have to break out the injection molding cylinders from the gray piece and clean up all the edges to make it fit together, haven’t bothered)
I would almost bet that it’s a 4.2vdc Li Ion (easy way to see is plus in 5vdc into the micro, and see the voltage on the B+ and B- [the charge voltage]), single cell…so you could put in 2 in parallel
That gets a flickering red tiny little LED in between the 2 USB ports
Thought at first it was Morse Code but it had no real pattern to its blinking.
Ah, looking at the board (first picture) there’s a label “RLED” next to the red emitter.
And a label “BLED” next to the one immediately below — likely blue.
Zero on the voltmeter across B- and B+ points
I’ll try it with a real li-ion cell at some point.
The holes next to the B+ and B- are where the contacts or wires to contacts would normally be soldered to. You most likely will have to at least temporarily attach a cell to be able to test any functionality. As for whether the cells should be series or parallel wired, all the ones I’ve used generally have a bus strip and the cells are in parallel.
That’s similar, but what they sent me isn’t that one. Probably from the same designer/source.
Hmmm, that’s an “OP-2”
I’d guess I have parts meant to be an “OP-1”
Differences: what I have has no opening nor switch for a LED, and no “battery display” — (guessing the 4 parallel openings on the case shown are for that)
Too bad they don’t show the innards of that one at DX.
Well there are a thousand similar things out there. I’ll check and see if it stops charging at 4.2v, or fails that test and decide if it’s worth doing anything with.
The IC on the top of the board, near the unshielded inductor is the boost converter IC, which means that one or both of the ICs on the back of the board are probably the charger IC (s). Unfortunately, can’t make out the markings in your photos, and given the tiny package size, even if we could, it might be a date code, rather than the part code. It is without a doubt a cheap one. TP4057 maybe. I’ve also seen the LTC4054 in cheap power banks.
On the topic of soldering to an 18650. I’ve experimented a bit. My approach, building on an initial suggestion from WarHawk-AVG, is clean/scuff the cell terminals, tin the wire, apply RMA flux to the cell terminal and the tinned wire end. Place the wire on the cell terminal, quickly press the top of the wire it very quickly with a hot soldering iron with a wide tip. Done right and the only heating of the cell happens by way of the wire, and if your timing is right, its never hotter than needed to melt the solder. I use eutectic solder too, which makes that transition to melting/sticking easier to see.
Not something I’d do for a larger pack, but for a couple of used laptop cells in a cheap powerbank shell, the calculated risk seems reasonable.
