abcGoodefg 18650 Battery Holder with Pin, 4 Slots 3.7V 18650 Battery Holder Storage Box Case 3 Pack

To small of wires to handle higher current..good for low wattage LED lights.I would of given 5 star if small wires were a little bigger.

I bought this for a mod to do with my old device, at first I didn't notice until the device just flat out refused to work. Taking a closer look revealed that the batteries are connected in series instead of parallel. Which means the Voltage is 3.7*2, NOT 3.7! I'm lucky to not have released the magic smoke but you should be careful when using it for 3.7v devices.

Very positive connections and I'm using on batteries that measure exactly 6.5 cm. The flat top style, not the ones all you kids use for your vapes and flashlights, the industry standard 18650 size cell that you can find and thousands of electronics across the globe. I'm using these to make parallel boards so I can rapidly charge and discharge high quantities of cells. I just use the wiring that is used inside your walls of your home and I strip the insulation off and solder it to the tabs on the back of these boards. First I hot glue the holders together, then I hot glue them to a board I cut that is just a slightly narrower than the tabs, then I solder on the copper wire, and then I can charge 36 of these batteries all at once with one charger. Yes they are slightly difficult by hand but you could simply put a string underneath all the batteries or do what I do which is just take a flathead screwdriver against the negative terminal of the battery and just kind of pop it out that way.Do not bend the tabs coming out of these, they will snap right off. That's the only downside, because if you could bend them then you could flush mount them on a piece of wood and the copper wire could just go to the side instead of behind them.

These are well made, sturdy, and durable. The only weak link is the thin gauge wires they chose to run from the battery contact and switch. I immediately replaced the wires with more rugged choices. Great value for the price.

It works

I'm really happy with the quality of these battery boxes. They are well built with sturdy plastic and I love the built-in on/off switch. I'm using Samsung 25R 18650 batteries and they seem to fit fine; snug but not so snug that it's stressing the box. My only minor issue is that one of the 2 batteries can be a little difficult to remove as the plastic on the switch side of the box is higher making it difficult to get ahold of the edge of the battery to lift it out.

Pros:Cheap quick way of attaching tp4056's to make a battery charging bank.handled a battery short (fire) and only slightly warped the plastic while still being usable.Cons:Extremely snug fit , deforms plastic housing if you cram a standard 18650 batterty in.requires you to squeeze the terminals with pliers to widen the slot so that an 18650 will fit without bowing the edges out,High quality contact pads are not cheap nickle strips that will fatigue and snap the instant you try to squeeze themRather thin plastic i believe is ABS.Hard to remove cells from without a pry tool or ribbon behind battery.MISC:I drilled out the mounting hole near one end to fingers width to easily push out the battery. This helps with processing tons of batteries.

I used one to rig up a power supply for XM radio for use out on a boat.* Other than the expected cheap construction and fine gauge wire (probably AWG 22 or 24), they are OK.They will hold standard unprotected 18650 batteries. However, Nuon 18650-1A protected units are both too long and too large in diameter to fit inside. This may be true for any protected 18650 - not sure of the dimensions.The contacts for + side of battery just barely protrude enough to contact 18650 units without nipples. I tightened one end up by flattening the small binding tabs (which bite into the plastic to hold in place) and putting some bits of electrical tape on the back to shim the contact toward the battery a small amount. Photo shows closeup with cover and inner cover removed. *I modified one to add a dropping diode and mini automotive fuse (soldered in) and was able to cram it inside the unit beside the switch, with appropriate bits of elecrical tape to protect the diode and fuse terminals. I used my own, slightly larger wire.

I use a LOT of these types of holders. This "brand" (whatever it may be) is TERRIBLE! The spring tension on the contacts is fine - nice and snug. But the plastic holder material is awful - thin and brittle. I've tried side by side comparisons with an identical holder from MPD (available through DigiKey), which is about twice the price. I used a wide variety of 18650 batteries for the test, both flat-top and button-top styles, of the correct length and diameter. This brand sold here cracked consistently from modest stress. It might be OK for a single-insertion use, but don't try to use it in any cyclic application. I pulled out the contacts and now use the holder only for battery storage.

Bought these for diy kits projects a few came damaged and was quicky replaced by vendor. they are for 18650 batteries flat top or smaller 18650 mAh batteries in length by 2 mm. read sizes before purchase regular protected batteries are slightly longer and are tight fit but doable.recommend these for your diy power supply projectsARG

Buen producto de material resistente y facilidad para soldar con estaño las terminales de cada posición de la batería

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Unit is good quality except that the wire thickness is very small. Would expect a little thicker wire.