Review: cheap 18650 mobile power bank

EDC Gear for Flashlight Carriers USB Power Devices
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Today I got twoo of these usb chargers/power banks from buyincoins… Its interesting that the white one has ETA9635 and the black one FM6316CE chip. Which one is better? The difference is that on the white one you cannot see the blue led during discharge and on the black one you can - very clearly (I even painted the cover black and you can still see the bright blue led). I will test charging my 9.7” tablet, which is rated for charging at 2A… Great little gadget, especially for the money…

@HKJ: Do you have any plans for testing this thing? I would love to see how it does on your detailed test… :beer:

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I do have one and hope to get it tested, but lately there have been many chargers.

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Be advised, smoked one already…the one with the FM6316CE chip in it…got INSANELY hot on the USB plug…the other ones don’t get hot…but that one…poof…let the smoke out

But this is what you get for $2.99 cheap Chinese chips…wish I could find some loose…I would unsolder that one and put another one on

I did put a blob of silicon RTV over the chip on 2 others…just to see if it helps move the heat way from the chip…but after doing some investigating…thermally conductive potting is better (maybe 2 part epoxy??)

It’s supposed to have thermal protection, but I think this particular chip wasn’t up to snuff

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… wonder if that’s across the board, I’ve 2 black ones on the way. Would expect these chips to behave a bit differently.

WarHawk - Thanks for the heads-up. Wonder if a piece of heat-sink two-part thermal epoxied would fit or help.
But based on this & the other things you’ve said maybe that ($15 fleabay) “ENB USB Power Bank 2x18650”/battery box that HKJ did review is worth considering. E.g. what is our time worth on these things :slight_smile:

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I ordered 1 each of White, Pink and Black.
I had to “repair” all 3.
The White one did not have the micro USB connector soldered sufficiently, I re-soldered it
The Pink one didn’t have the spring assembly soldered to the circuit board. I soldered it.
The Black one did not have the spring installed in it’s slot, I had to do that. An easy fix.

Pics of all 3 with the board removed and upside down.

The Black one has a different circuit board and chip as mentioned by others. White and Pink have the 9635, while the Black is the 6316.


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I had one that had a cold solder joint on the + spring post (the light would kinda flicker on charge…hmmm)…a quick hit with a 50watt solder tip and viola

I put some clear silicon RTV over the chips as a heatsink conformal coating/potting to see if it helps [just a glob on the chip and let it self level and harden]…these chips get quite hot when they are charging out (I believe they are current limited IN to 500mA so not as stressful on the chip or the battery) they should have thermal protection in them though (per the data sheet)

There is maybe 1/16” space under the board to the bottom of the housing when the board is inserted so maybe putting a small heatsink would help but there isn’t much room and no airflow so there is really no benefit from a heatsink, I was thinking perhaps the potting would wick the heat away and into the surrounding board thus giving the thermal path a larger surface area to dissipate (but I’m no electrical engineer, I just know thru my military experience dealing with silicon/RTV encasulant and conformal coated boards, the heat would migrate away thru the conformal coating)

Maybe I am just overthinking a cheapo charger

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First Hi, I especially signed up here to talk about these :wink:

For me it is the same with two different chips, my half black/half white one uses a FM6316CE and the White one an ETA9635. The FM chip uses less external parts, 9 C’s and R’s or LEDs, not counting the big diode (SS24 for me). The ETA uses 11 C’s or R’s or LEDs. The FM board says CHD-XS V1.1 and the ETA board says ZS-001.

In my case at the start both worked fine, with the FM6316 also lighting Blue while being discharged and being at about 4V idle (Multimeter measured), it only went to 5V on discharge, so it somehow detects discharge? I first though this is nice!

However, this didn’t last very long, after trying to charge Tablet and Phone a few times (just for some seconds or minutes) it didnt charge any of them anymore and the blue light also didn’t light up. Now it is permanently at about 4,1V output - however this is NOT the direct battery voltage, which I thought first - it is always slightly boosted. Interestingly it drops slightly (idle) (to 3,9V) when it is getting charged. The USB-Out Plug is also minimally heated while the battery is connected (didn’t check if it also was before), so probably it’s draining power unneccesarily - charging works however!

I checked the board and didn’t find any bad joints. I also resoldered some to be sure… So I guess the FM chip is fried - But at least I might be able to use it as charger-only. Good that I ordered two of these Powerbanks, but really strange that they don’t only differ in Color.

My guess is the FM-variant is the cheaper-made and newer variant, because it also has fewer external parts. But overall, both of these small PCBs had some parts not populated, either this is just for a different setup, or there were some protection and stability elements of the circuit removed. If I would know, I would be happy to add them, but the datasheets to these ICs are quite bad …. (Thanks for the google translate link to the FM datasheet by the way!)

Btw. I actually ordered them to try if they would work as a Raspberry Pi uninterruptible power source (UPS). I tried the ETA based one (as the other was dead before I could do that, like I wrote before…). The output voltage dropped too much, to 4,4V at the two relevant measurement points on the raspberry pcb (while it is spec’ed for 4,75V - 5,25V, 700mA, though they recommend a 1300mA+ power supply). So they really don’t seem to put out a stable voltage at higher currents :frowning: or maybe I should try to find if this can be changed by a resistor.

(Got the ETA9635 “datasheet” from there: http://www.datasheet4u.com/datasheet/E/T/A/ETA9635-ETC.pdf.html - anyone knows a better one?)

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I had 3 that all seemed to be working OK but you guys got me curious. I pulled the guts out of the plastic housing and broke off the mini-USB port. I did try to be careful. My skills aren’t up to re-attaching that little thing. Pretty fragile little part. I pulled off the copper pad on one of the 4 feet anyway so doubt I could have ever gotten a decent connection.

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The law do diminishing returns. It goes both ways.

As you try to increase the performance of an item, the cost goes up with less and less improvement.

On the other end, as you try to lower the costs of an item, you reach a point were each cost savings that you implement impacts the performance more and more until a point is reached were functionality is lost.

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So I got my couple black ones of these, both with FM6316CE, and not too impressed. It seems now & then I have to (re-)learn this, but yes one almost always gets what one pays for:) And when something appears “good” & perhaps popular (e.g. ETA9635 implementation), you can bet someone will try to cheapen it, maybe even below usability (like dchomak related).

What mine does OK: Charging its battery (at least it cuts off about 4.2v), RED LED during charge then BLUE when done. Charging iPod & iPad at the max rate I’d want the little thing to do.
What mine doesn’t do well: Cutting off battery (I pulled plug at 2.3v) or indicating battery state during discharge (no LEDs lite on mine during discharge). Controlling heat, as WarHawk noted the parts on this get hot at high or continuous discharge rates - in particular the SS34 diode, a bit lesser for the chip & coil.

So can’t use unprotected cells in mine due to the apparent lack of low-voltage cut-off…. Unless maybe tacking on one of those cheap Mini DC Red LED Panel Voltage Meters on the box to keep an eye on it.

IMO if you can assure your purchase has ETA9635 it may be fine, otherwise stick to proven/tested stuff.

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Not cutting off that you noted really disturbed me. So I checked mine. (It just never occurred to me to check for this.)
My black unit has the 6316. When using it to charge a device, the 6316 will suck the 18650 all the way down to zero.
My 2 others have the 9635 and cut off discharging the 18650 at about 2.75v - 2.80v. It’s not actually a sharp cutoff but is gradual decline.

So to repeat what others are saying, the units with the 6316 are bad.
The units with the 9635 are good.

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Woo, thank you Cfcubed and Dchomak. Very good safety info. Going to check mine right now.

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Shoot. I just I should be somewhat happy that I only ordered 1 black one (I think) when I made my 2nd order for a whole bunch for gifts :~ . If I don’t bother to fix that one than maybe I’ll only keep that one for myself and use it sparingly (+ safely.)

In any case, thanks for the good detective work guys! It helps keep oblivious people like me safe with things like this…

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OH SNAP! I forgot I have like 3-4 of those little .36” voltmeters just laying around…going to be modding one of mine to monitor the voltage…

I snapped the USB micro connector on a Xtar MC1 3x times…carefully soldered it back down…well last time it came off I got pissed and used a flathead screwdriver and stripped the board…just shoved the components off like a bulldozer, then soldered a pigtail and one of those thin TP4056 boards on it and super glued the base back on…and wouldn’t you know it…works like a champ (broke the daggum spring tonight and said to hell with it…ain’t gonna fix it again…just cut the charger module and chucked the whole thing [I really do like those slider charge holders though…uggh…recovering and will try to mod it with a pen spring or something] {correction, the bottom flexed and the spring jumped off the round holder…I cut off the pigtail in error…DOH!:smiling_imp:

I also built a 4x 1s4P board with the voltage meter on it, I charge 1 battery at a time or ALL 4 out of my SRK (I know better than mix/match different level batteries on a single channel)

I’ll mod one of these little ones and do a full discharge and see where it stops and then do a full charge to see where it stops…I can say the ones that I put the silicon/RTV run more “stable” but like I said, I’m no electronics engineer

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I’m waiting on my order of 5 too. And i’ll demand a refund for a those 6316 i get!

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Looks like there’s confirmation that the units w/FM6316CE implementation are unsafe for use with unprotected cells, they’ve no low battery voltage cut-off or indication. And as OP/chiefinspectorfinch indicated, and the tight fit backups up, no (few?) protected cells will fit.

chiefinspectorfinch - Please consider amending the first/original post of this thread with this info. I, like others, do not always read review threads to the end & might miss this important info. We also cannot be sure that ordering a white one will always get you a safe/ETA9635 one.

Two ways to tell you’ve an unsafe or FM6316CE one:

1) you don’t have to take it apart & risk what happened to flydiver… Here’s a (crummy) photo of the top side of my unsafe/FM6316CE - compare to equivalent/last pic in first post in this thread (e.g. the black 0 ohm resistor next to soldered spring (likely a cold solder joint BTW)):

!!

2) a simple run-down test w/DMM & clip leads w/unit charging something that’d use all its power. Of course be VERY careful not to short cell.

IMO not sure you can fault the seller of bad ones if the transaction is good otherwise. He’s likely not the designer, he’s just pushing product. Perhaps informing of this thread / asking for one w/ETA9635 (top side looks like chiefinspectorfinch’s photo) would get you somewhere but I doubt it.

Again best to stick to proven/tested stuff (e.g. see HKJ’s site). But as even tested products can change over time guess sticking w/names/reliable suppliers OR maybe carefully comparing photos of guts is something.

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I was alarmed when I read this so I checked my powerbanks and found that one of the yellow banks (I have 10, 2 per color) had 6316. I charged this particular powerbank 4 days ago and placed it aside for future use. When I took the readings, the new unprotected Samsung ICR18650-28A reads 0.96 volts which means that it discharged by itself and drained the cell below safe levels.

Now I’m not sure whether I should recharge this cell but I’m pretty sure I’ll never use this particular powerbank again. Will it be safe if I recharge this drained lithium ion using a NiteCore i2? :~

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Well I went ahead and charged the Samsung ICR18650-28A with 0.96 volts using my NiteCore i2 and observed that it reaches 3 bars (full charge) from 1 bar in a few seconds so I immediately removed it from the charger fearing that something bad might occur. :open_mouth:

I took the readings and its now 2.25 volts? :~

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Some1 should inform BIC of this fiasco before anyone gets hurt!

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With all the crap-chargers and CrapFires they sell, I guess they don’t care.