Review: cheap 18650 mobile power bank

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Nightbird95
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flydiver wrote:
Nightbird95 wrote:
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. Shocked

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

0.96v is essentially dead. It doesn’t take much to push them back to a much higher voltage on that steep part of the discharge curve. If you can hook it up to a low volt/low output dumb NiXX charger for about 5-15” then check it again. If it’s up to 3.0v or higher then try the i2 again. Watch it carefully.
If it won’t take the charge > discharge and trash.
If it will > mark it clearly and consider it a ‘wounded’ cell.
If you don’t care for the risk (there is some) you should simply discharge and trash. If you aren’t sure > trash it. Better safe than sorry for a few $$.

Thanx for the tip flydiver. It now has a big red asterisk mark.

I charged it with the i2 (it wont fit the NiMH charger and my other charger is an i4 which has higher output) for several minutes and was in the 2-bar range when I removed it to get the voltage reading – its 4.05 volts. I guess this cell can still be fully charged then.

rollinstone157
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In the latest AliExpress sale, I ordered 20 of these to give out to people. I ordered the white ones, but if they come with the 6136 chips I will be filing a dispute. Because the implementation of the 6136 is just laughably bad.

dchomak
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I just checked for parasitic drain on the 1, 6316 that I have.
With a fresh cell (4.15V) the drain is 17 uA
But a with a damaged cell (1.92V) the drain is 111 uA.

I also confirmed that the 6316 will attempt to give more than it should . An iPad received over a 1.7A (they need 2.0 ) and a GPS unit for my car got 1.7A. Both are too much for this little unit. Chips started to get hot very quickly.

flydiver
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Nightbird95 wrote:
I charged it with the i2 (it wont fit the NiMH charger and my other charger is an i4 which has higher output) for several minutes and was in the 2-bar range when I removed it to get the voltage reading – its 4.05 volts. I guess this cell can still be fully charged then.

It could be OK if it was a newer cell and you caught it quick. The older and the longer at very low voltage the more the damage. Damage will first show up as higher resting drain and lower performance under high draw.

To Air is Human, to Respire….Divine.

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bluey wrote:
I also informed the shop where I bought it (eBay Shop from “keyzone”) with a link to there, also to get a refund for the black one that was defective after 5mins.

I would guess that nobody really gets hurt, or rather equally bad for both chips. Only the battery cells will get damaged with the FM6316 because of the discharge issues, but they won’t get shortcircuited or overcharged. At least from the current information we have. Of course both of these chips/designs could still have some other issues. When looking at the poorly detailed datasheets it looks like “anything could happen” ….

// Edit: Ok afterall the datasheet of the FM6316 seems to be actually more detailed than the ETA one, at least what you are showing here and what I found for the ETA. And like you said, maybe poor implementation, wrong current limiting resistor? I will check mine at another time…


That’s what I don’t understand…per a translation of website pertaining to the FM6316CE
http://www.microsofttranslator.com/bv.aspx?ref=SERP&br=ro&mkt=en-US&dl=e...CHS_EN&a=http%3a%2f%2fdetail.net114.com%2fchanpin%2f1005536377.html
Quote:
First, an overview
FM6316 is a software application for mobile power supply , the integrated lithium battery charger, DC-DC converter step-up current-limiting, and load testing functionality in one portable power management IC.
FM6316 integration including trickle charging, constant current and constant voltage charging charging charging mode, the system closes the output in a charged state discharge path, when the external input to the power supply when removing, FM6316 powered from battery to external devices, if there is no external device access is detected, the system enters the standby state, the entire system standby current 16uA. Constant current charging current and voltage boosting current value by external resistor programmable.
FM6316 has multiple protection design, including load over current protection, charging anti-flooding protection, short circuit protection, soft-start protection, overtemperature and undervoltage protection. Where FM6316BE is the limit of, FM6316CE is an open-ended flow, discharge current maximum is 1 a.

Second, characteristics
Simple peripheral circuit;
No load testing shutdown;
Standby current 16uA;
Constant-current/constant-voltage trickle/three-stage charging;
IC boosting efficiencies up to 90;
Boost current limiting output;
Load flow and short circuit protection;
Constant current charging current values can be externally programmed;
Boost limit value can be set by an external program;

Third, the package:
FM6316BE and FM6316CE in the SOP-8 package, FM6316E ESOP-8? Yu? br/>
IV product application
Mobile power supply;
IPAD and other digital equipment power backup.

If it was working as designed these chips “should” thermal/current limit to 1A and charge the li ion with the correct CC/CV…but alas…it appears that either a bad design or bad components on the board…unknown at this time till someone with ALOT better test equipment can see just what these boards are doing…hmmmm

So far all 4 of my other FM6316CE driven boards are doing what they are supposed to do on charge…all of them give blue on full charge, using one of those .36” voltmeter I get 4.2 on the readout, and on power out they run whatever device just fine and don’t get warm, the one black one however smoked after a few hours (I need to get a USB doctor module)

I am getting one of these for sure…maybe 2 or 3
http://www.dx.com/p/usb-av-usb-power-current-voltage-tester-translucent-...
Give me something for easy volts/amps diagnostics


BLF review thread
http://budgetlightforum.com/node/23964
tedm
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I have a similar type unit, but it is a cree flashlight, with the USB input and output on the tail, where a metal plate rotates.

I’ve used mine to top up various android and windows phones, and it works, but if I were relying on it for charging, I’d probably skip the flashlight, and go for one of the 4 pack cases, that are < $10. Also, makes a great storage bin for charged batteries.

Now if those 3-4 emitter x 4, (Skyway, etc.), had USB chargers on them, those would be very interesting, but the on/off switch makes those lights useless for my needs, and rather large diameter wise.

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I bought one of these http://www.ebay.com/itm/350919777680?ssPageName=STRK:MEWNX:IT&_trksid=p3... and probably paid too much. First I was hating on it. It was totally dead until I found a momentary micro switch inside and pushed it. That brought it to life. It came with no instructions. I filled it with laptop pulls and it seems to work great. I don’t know if it’s the full 2A, but it charges my Galaxy S4 fast and that uses a 2A charger. A 1A charger on the S4 is takes forever to charge it so I’d say 1.5A-2.0A at least. It also charges up ok off a PC USB port or any good MINI USB charger connection. I don’t remember if I used USB 2.0 or 3.0 port. This is just a FYI. I could review it, but I imagine there are better out there. Heck, this same one is probably on other sites for $3.99

- Joe

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flydiver wrote:
Nightbird95 wrote:
I charged it with the i2 (it wont fit the NiMH charger and my other charger is an i4 which has higher output) for several minutes and was in the 2-bar range when I removed it to get the voltage reading – its 4.05 volts. I guess this cell can still be fully charged then.

It could be OK if it was a newer cell and you caught it quick. The older and the longer at very low voltage the more the damage. Damage will first show up as higher resting drain and lower performance under high draw.

It is a brand new Samsung ICR18650-28A and it should have stayed at 0.96 volts for not more than 4 days because I charged it 4 days prior to checking my powerbanks.

I’ve finished charging it to 4.18 volts and I’ll just place it aside for a while. If it looses its charge on its own after a day or two then I’m throwing it away. Smile

dchomak
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Nightbird95 wrote:

I’ve finished charging it to 4.18 volts and I’ll just place it aside for a while. If it looses its charge on its own after a day or two then I’m throwing it away. Smile

If you want to check a cell for leakage, try watching it when it is around 3V. The discharge curve is MUCH steeper there and you will be able to notice the leakage more readily.

(Remember when that cell originally discharged to 0.96V? It didn’t take much to get it up to 2.25. That’s why it is best to check for leakage when the cell is discharged.)

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dchomak wrote:
Nightbird95 wrote:

I’ve finished charging it to 4.18 volts and I’ll just place it aside for a while. If it looses its charge on its own after a day or two then I’m throwing it away. Smile

If you want to check a cell for leakage, try watching it when it is around 3V. The discharge curve is MUCH steeper there and you will be able to notice the leakage more readily.

(Remember when that cell originally discharged to 0.96V? It didn’t take much to get it up to 2.25. That’s why it is best to check for leakage when the cell is discharged.)

OK thanx dchomak. I’ll do that. Smile

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So far 1 out of 5 had issues…all the other ones are charging/discharging properly

dchomak
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WarHawkAVG wrote:
So far 1 out of 5 had issues…all the other ones are charging/discharging properly

Is it because 1 of 5 is the 6316 and the other 4 are 9635?
What are you saying.
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dchomak wrote:
WarHawkAVG wrote:
So far 1 out of 5 had issues…all the other ones are charging/discharging properly

Is it because 1 of 5 is the 6316 and the other 4 are 9635?
What are you saying.

I’m saying that 4 of the 5 I got with the 6316’s are working fine…one of em smoked in a day

All of mine have the 6316’s (I ordered mine from a different company that buyincoins

Could be just crappy China QC or bad chips…who knows

I did put the .36” voltage meter on one of my black ones that was working after I drained it down to where it would quit charging…stopped at 3.3, charging stops at 4.2 [it is also one of the ones I put a RTV blob over the IC…but who knows if that is the reason…might just cause it to smoke too]

Will keep monitoring it

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The reason I asked is because my 6316, the one that will discharge all the way to zero stops at about 2.8V when charging an iPhone 3GS. That is the iPhone refusing any more current. So I suppose one could get a false sense of security by testing the discharge characteristics with a device like the iPhone. That would be a “gotcha” just waiting to happen.
To test the discharge characteristics of the 6316 and 9635 I used an 82 ohm resistor spliced into a USB cable. The 9635 stops at about 2.75V, the 6316 goes right on down to 0.

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hmmm…I haven’t tested mine like that yet

Not good to drain to 0, yikes

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Spent too much time on this already but wanted to reiterate what myself, dchomak & others have found w/our FM6316CE implementations of this thing.

Although fabricated/resistor-based tests like dchomak’s are important & objective, our FM6316CE-based units fail to behave properly in common usage (e.g. my IPad 2 tests). Like dchomak related these devices must not rely on the thing being charged to limit draw or stop drawing when voltage falls.

So of the THREE tasks the device must perform to serve its function; charge battery safely, cease draw when battery gets low (e.g. 2.7v) and charge things attached to it while limiting current to component maximums (e.g. 1A per FM6316CE datasheet) – it may do ONE of them correctly (charge battery).

And based on dchomak’s parasitic drain test, lack of low voltage cut-off further punished the discharged cell – fully discharging it when left unused/idle. We know this irrevocably damages the cell & elevates risk in recharge – something the target users will know nothing about, they’ll just keep charging it.

Yes, better testing ala HKJ would be nice (stop pestering him WarHawk Wink ), I don’t need this to know not to use my FM6316CE-based units. And who knows which implementation HKJ has & will eventually test.

I’ve placed my order for the “ENB USB Power Bank 2×18650”/battery box, that HKJ did review, for this task. But to each his own.

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cfcubed wrote:
t. Yes, better testing ala HKJ would be nice (stop pestering him WarHawk Wink ), I don't need this to know not to use my FM6316CE-based units.

It is fine that people ask me to test specific equipment, that helps me decide what to buy & test.

cfcubed wrote:
And who knows which implementation HKJ has & will eventually test.

Not me, I have one, but have not looked at it yet. It is in the todo pile.

Note: Not everything in my todo pile gets tested, sometimes I remove stuff because it is to old or to difficult to test.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

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Have you measured how far it drains the cells? I just ordered one of those $5 meters from dx, and would like to get a 2 or 4x pack like this one, if they don’t drain the cells too low (or charge too high).

That’s odd about the micro switch. If I found them for $4, I’d probably buy them for the shells, but at ~$10, I’ll wait, as I have several other USB chargers already, and for most devices, spare batteries.

Let-There-Be-Light wrote:
I bought one of these http://www.ebay.com/itm/350919777680?ssPageName=STRK:MEWNX:IT&_trksid=p3... and probably paid too much. First I was hating on it. It was totally dead until I found a momentary micro switch inside and pushed it. That brought it to life. It came with no instructions. I filled it with laptop pulls and it seems to work great. I don’t know if it’s the full 2A, but it charges my Galaxy S4 fast and that uses a 2A charger. A 1A charger on the S4 is takes forever to charge it so I’d say 1.5A-2.0A at least. It also charges up ok off a PC USB port or any good MINI USB charger connection. I don’t remember if I used USB 2.0 or 3.0 port. This is just a FYI. I could review it, but I imagine there are better out there. Heck, this same one is probably on other sites for $3.99

- Joe

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Cfcubed wrote:

Spent too much time on this already but wanted to reiterate what myself, dchomak & others have found w/our FM6316CE implementations of this thing.

Please don't feel that way about taking our time.  You provided very important safety information to us which I, and I'm sure many others, are very grateful.

Thank you also to the OP for for posting a notice at the top of the OP. This is a very good thread.

I'm going to convert my "bad units" to dedicated chargers.

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… and it wasn’t too much time as I’ve spent some more:)
Reviewing the FM6316CE datasheet & PCB think I’ve isolated its problems root causes; no Output Current limit resistor from chip pin #2 to ground (UPDATE: useless as it doesn’t t lower draw to 1A rated max, so another chip flaw), and FM6316CE itself does not implement the battery undervoltage protection it says it does (no external components control this – it appears an unimplemented chip function).

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So is it possible with some DIY, to improve this power bank, or is there a software problem also?

Finaly, proud owner of a Powerex Maha mh c-9000 for my Eneloops:)

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IF I’m correct, low battery cutoff function is absent/faulty in the chip itself & so is not fixable… Other than (the silly notion of) replacing it with a different/working pin-compatible one.

My/our FM6316CE versions look like reference implementations (less the useless OutputCurrent limit resistor – not respected by chip), so IF I’m right any/all devices using this (version of the) chip lack essential/advertised low battery cutoff / undervoltage protection. Hard to imagine but perhaps representative/indicative of lower-tier chip design/development/production houses.

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You can maybe limit the output current more by increasing the resistor at the prog pin. If that schematic is correct: http://budgetlightforum.com/node/29223?page=1#comment-553827 – But then it will probably still over-discharge the battery in terms of capacity (just not in terms of “too high current”)

When measuring my half-broken one (only still charges correctly, output is only at 4V at all times), I measure 36 Ohm from the Prog Pin to GND. Though there is no 36 Ohm Resistor on the board, so maybe it is burned/fused-together at some point inside the chip, but I can’t really say. Maybe someone with a still functioning board could try.

Overall though: I wouldn’t rely on these for critical applications, and would always expect it to start a fire… (I would do the same with the ETA-based ones though…). So don’t leave it on a pile of paper while leaving the house for more than 5 minutes….

Maybe using them with protected cells (short-cut and over-discharge protected) is a viable solution…

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Hmmm,
by the way, did anyone search if these ICs are maybe renamed “fake”-versions of high end ICs from for example Texas Instruments, Linear Technology, .. ? (catchword “Power Management ICs” I’d say) So maybe one of those chips could in theory be “dropped in” (though probably you wouldn’t waste one of their ICs, but also want to add those few remaining resistors and capacities for a complete high quality design then)

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Thanks for the 411 on all of this.

On the ones in bound to me with a FM6313CE circuit I’m going to toss in a DIY protected 18500 cell pull I just slapped up (only made 1 so far as a test.) I made one for use with a 18650 battery carrier & thus did not use tin strips but just plain ole 24~26 gauge wire. Hopefully that will make it somewhat safe to use. I won’t rely on the protection PCB (dissected from an old AW CELL) to prevent overdischarging each time but hopefully it won’t fail on the times that I do need it to work.

Just to be safer -> I won’t gift these away and keep their limited usage for myself.

AZ

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Don’t like the phrase but when something sticks in my craw I’m compelled to follow it to the end. So I tried adding the absent Output Current limit resistor from chip pin #2 to ground, to try to reduce the max current to 1A chip can safely handle. FM6316CE spec says it configures the output current limit from 2.5A – 0.5A using range 10k – 100k to ground. Found adding any such resistor raised the max current, the lower the resistance the higher the allowed draw (e.g. 10k resulted in about 2.2A draw into IPad). Tried 10k, 22k, 47k & 100k – all had bad effect of raising max current draw BUT also resulted in the BLUE LED lighting dimly during discharge – going off when batt dropped to about 2.6V (but not stopping drain/draw).

So I’m finally & fully done with this:) My research & testing suggests at least 2 faults in this FM6316CE chip itself, e.g. deviating from its published spec, neither battery low voltage cut-off OR current draw limiting (to <= its 1A rated max) are implemented properly or at all.

This seems to leave 2 possible uses for these FM6316CE-based units, with the only(?) cells that may fit – unprotected ones, charging batteries OR discharging them to proper storage charge (monitoring w/DMM to 3.6v -3.7v) then removing them. DIY hacker types could have fun adding a $2 Mini DC voltage meter + momentary switch for monitoring and just make sure they don’t charge things that draw too much.

Again an HKJ-reviewed “ENB USB Power Bank 2×18650”/battery box is what I’ll be using.

bluey – WRT your broken one measuring “36 Ohm from the Prog Pin to GND” must be toasted – my “working” ones measure more proper 1.4k.

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Thanks for the update CFcubed.  Your efforts to test and report on these units are much appreciated.  Also your efforts to see if the issues could be fixed.  Your tips on how to identify the bad units in Post 53 should be handy.  I have come across 2 chargers (one black and one blue) that have the bad chip, but are configured differently.

Here are a few pictures.  First on is like your to show how to identify from the top.  Has 2 resistor perpendicular to tail wire and different led and other components configuration.  Mouse over zooms in to the 2 resistors.

Bottom.  Looks like dchomak's black unit.

Before I forget.  Welcome to the forum Cfcubed!

So far, BIC is telling me they can not refund for the bad units.

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I just used one of the 2 "bad chargers" that I mentioned in the above post to charge a couple phones to see where it would cut off.  Halfway through discharging the second phone, it stopped charging.  It flashed the blue led when it cut off.  My wife quickly disconnected it before I got a chance to check the voltage.  I did check the voltage within one minute of it cutting off.  The cell was at 3.3x volts.

The charger was definitely running hotter than seems appropriate.  I had the lid off.  I think it would have been too warm with the lid on.  I didn't check temperature or current while it charged.  I will try another run sometime this week and report back.

I don't know if good units also get hot discharging.  I think I will pot mine with the first recipe from here anyway.

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Good additional data esp. the nice photos, so looks like there may be several variants of this thing. IMO most/all(?) of the research/testing WRT FM6316CE-based ones should still hold…. E.g. think any FM6316CE-based ones that cease charge prior to nearly or fully discharging cell (e.g. to below 2.2v) are only doing so because the device being charged is ceasing charge due to low USB voltage.

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Good point.  I don't know why this one stopped yesterday.  It would be nice to know the cell voltage under load just prior to it stopping.  I'll try to capture more info next time.  Maybe tomorrow.

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