Two Types of Holders for 18650 Batteries

Today I decided to write a very short review of some small but useful things: holders for 18650 batteries. Naturally, there are pros and cons. More after the jump :)

I didn't order these on August 25, but a little later. They arrived very quickly, which surprised me, since I still hadn't received all the items I'd ordered on August 25.
Anyway, this is a mini-review in the “look what arrived” series :)

The key difference with these holders is that they use flat contacts instead of springs. I think this should improve the contact between the battery and the terminal.

I ordered the holders from different sellers, but they were shipped and arrived at the same time. What's more, they were packaged almost identically. I even checked the sender's postal code, but it was different, so I was sure they were from the same seller :)
They arrived in black bags, thoroughly wrapped in sheets of polyethylene foam.


The four-cell holder came in a resealable bag, while the small ones were individually bagged.


Let's start with the large one.
Link to the product. I bought it for $ 1.81


There were 5 small ones in the lot. There was a discount when I bought them, and they cost $ 2.14
As I mentioned above, they came individually bagged, and even had the part number printed on them, which is quite unusual for items from Ali.


The single-cell holder is exactly like one cell of the larger holder, with the same terminals. From the outside, it's simply a “piece” of the larger one.


Both types of holders have contacts for soldering into a circuit board, and the contacts are 1.5 mm wide. The holders also have mounting holes (presumably) 3 mm in diameter.




The distance between the near contacts is about 19.33 mm (58/3).


The distance between the far contacts is 72 mm.


At first I thought I'd list all the measurements, but then realized it would be easier to make a drawing.
The single-cell holder is exactly the same length as the large one. It's a little wider than 1/4 of the large holder, measuring 21 mm.


Since all the contacts in the large holder are independent, and the contact arrangement is the same for positive and negative, the manufacturer marked the polarity for both possible configurations.
I find it a little confusing, since from above it's not clear whether the batteries are connected in parallel or in series.




The contacts are held quite firmly in place. They don't wander around or try to come out with the battery, even when the holder isn't soldered in.
This contact design works better at high currents, since a regular spring has a smaller cross-section and is longer (especially if not all the coils are touching, which happens very often.


Naturally, I had to try inserting a battery.
The unprotected batteries fit snugly and didn't wobble, so there were no problems inserting them.


But my attempt to insert a protected battery ended in complete failure.
I simply couldn't get it in. Apart from not using it at all, there were two options:
Break the holder.
Insert the battery, but then be unable to remove it.

Speaking of removing them, unprotected batteries installed in the middle slots are hard to get out. You can't remove them without a tool because there's nothing for your fingers to grip.


The problem with protected batteries is simply that they're longer.
The “unprotected” batteries were 65.1 mm long and fit snugly; the protected ones are 68.1 mm long and won't fit.
I think the maximum battery length these holders can accommodate is about 66 mm.


And that's my little review.
The product's strong points are its good build quality and the more suitable spring design for connecting the battery.
The sellers also deserve credit for decent packaging and fast delivery.

The product's downsides: it doesn't fit protected batteries, and the middle batteries can be difficult to remove.
The sellers' downside: neither order had tracking, though tracking is rare at this price.

In my opinion, these are excellent holders, but they only work with unprotected batteries. In return, they provide good contact and lower losses than regular holders with round springs.
I'm not sure what to say about the price; it seems quite reasonable to me.

I don't know if this review will be useful, but I thought it might come in handy for someone.