Review: Efest 18650 2600mah protected button-top

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Overclocker
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Review: Efest 18650 2600mah protected button-top

First off this ain’t gonna be an extensive review full of graphs and such. With that out of the way let’s get it on shall we?

The most interesting thing about this 18650 is the length which is approx 67.7mm according to my precision measuring apparatus :bigsmile: Yep that’s in flat-top territory folks but this is button-top and protected at that… How was that achieved? Read on…

Instead of a traditional set-up with a button spot-welded onto the top with a metal strip running down the side into the PCB at the bottom, this Efest instead has everything on top. A thin metal cap fits snugly onto the end of the Sanyo cell (yep this is a Sanyo cell) and thereby presses a thin PCB onto the (+) button of the Sanyo. While the metal cap provides the (-) electrical connection to the PCB. THere is nothing spot-welded so i can’t say how reliable this setup would be in the long-term

This means there is no need for a metal strip to run along the side of the cell thereby eliminating the risks of shorts should the insulation fail (which is usually just a very thin layer of kapton tape) so safety is theoretically improved.

At this point you might be wondering where the electronics are. Well they’re inside the button :bigsmile: Which brings us to the most important issue. The limited real-estate inside that tiny little button means you can’t put beefy electronics inside there. The protection cuts off at around 3.0A so you can’t use this in high-power applications.

So in the end you just have to weigh the pros and cons. On the the one hand it is very short for a protected button-top so this is definitely a good thing for those older flashlights that don’t like long cells. And to reiterate, safety is also improved since it doesn’t need to have that metal strip along the side.

On the other hand the protection cuts off at ~3.0A so you can’t use it with, for example, the Foursevens Maelstrom X10 which is specifically designed for 26650 anyway. I think this battery will be just fine with most “normal” flashlights putting out below 750 lumens OTF but don’t quote me on that.

Finally here are some runtime numbers since no review is complete without numbers LOL just take them with a grain of salt because different cells have different discharge curves therefore these numbers won’t be directly comparable. Test flashlight is the Maelstrom X10, until the built-in overdischarge protection kicks in:

-Efest 2600 (w/o PCB): 0:55
-Sanyo UR18650FM (bare cell no PCB): 0:55
-Panasonic NCR18650A (bare cell no PCB): 1:12
-AW 2900 protected: 1:04

Edited by: sb56637 on 08/26/2014 - 17:45
Woody
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Interesting. Presumably without the strip along the side it might fit into, say, the Roche F12, which is on the thin side (I use Sanyo unprotected 2600 – my Panasonic based 3100’s are too wide, or too long)?

Kokopelli
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Have you noticed if it had low voltage protection too?

I may use these for my XPG lights and 2×18650 setups if there is a low voltage cut off too.

Overclocker
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Woody wrote:
Interesting. Presumably without the strip along the side it might fit into, say, the Roche F12, which is on the thin side (I use Sanyo unprotected 2600 – my Panasonic based 3100’s are too wide, or too long)?

well it doesn’t have the strip but it does have a metal cap that goes all around the entire circumference of one end of the cell which does make the cell wider. good thing Efest applies their label NOT over the part with the metal cap Smile

take note i’m talking about this version with GOLD label

there is an older version with WHITE label that have some problems fitting into some of my lights

Overclocker
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Kokopelli wrote:
Have you noticed if it had low voltage protection too?

I may use these for my XPG lights and 2×18650 setups if there is a low voltage cut off too.

yep it has low voltage cutoff. around 2.4V i think. will try to measure later

m
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What camera do you use for the pic’s???

need to buy a new one before the holidays Sad

Overclocker
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m wrote:
What camera do you use for the pic’s???

need to buy a new one before the holidays Sad

sorry about the above pix, lighting was too harsh

cam is the Nikon J1 w/ kit lens 10-30mm. heres a better pic from the cam:

i like it, pretty good cam. but if you can spare some more cash go for the Sony RX100 Smile

Boaz
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Do you have a link to this battery?

       καὶ τὸ φῶς ἐν τῇ σκοτίᾳ φαίνει καὶ ἡ σκοτία αὐτὸ οὐ κατέλαβεν

                            

       Dc-fix diffuser film  >…  http://budgetlightforum.com/node/42208

Overclocker
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Boaz wrote:

Do you have a link to this battery?

i thought you wouldn’t miss the banner ad :bigsmile:

btw this isn’t a review sample. i actually paid for this batt that i dissected. and i’m in no way affiliated with them.

NightCrawl
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Seeing this makes me wonder.. why dont we see + pole mounted PCBs more often? No flimsy wire, possibly smaller to build.. why is that so rare?

Shadowww
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NightCrawl wrote:

Seeing this makes me wonder.. why dont we see + pole mounted PCBs more often? No flimsy wire, possibly smaller to build.. why is that so rare?


Partially because obstructing vent holes isn’t particularly excellent idea.
scaru
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Shadowww wrote:
NightCrawl wrote:

Seeing this makes me wonder.. why dont we see + pole mounted PCBs more often? No flimsy wire, possibly smaller to build.. why is that so rare?

Partially because obstructing vent holes isn't particularly excellent idea.

True, but if they put a couple holes in it wouldn't that prevent that problem?

sb56637
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Thanks very much for the review! Frontpage’d and Sticky’d.

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