Review: cheap 18650 mobile power bank

All 20 of mine arrived today…and all 20 have the 6136 chip. Brilliant. To those who have said they have no overcurrent protection, I shorted a usb cable through my multimeter and it was trying to push 5A. I only wanted to test one but the results were certainly concerning. My Ruinovo 6x-18650 box cuts before the multimeter refreshes past 1.5A, and requires a push of the hardware button to reset the breaker.

Dissappointed

EDIT: Also, no over-charge protection either, I’m filing a dispute with the vendor so I’m sacrificing a laptop pull and I want to see how high it will charge it.

Hm interesting one of the new FM3616CE based ones (with SS34 diodes in my case versus my previous with SS24) does have the blue led become more and more dim after the battery reached 2,5V. After that with a multimeter I saw it going down to about 2,38V when I disconnected it. By now the cell has recovered to 3,72V (still rising, this was just minutes ago…).

To say something positive, the FM3616CE might actually try to keep the cell at 2,5V, by cutting-off at 2,5V - but with a bad implementation that already begins to discharge again at 2,50…01 V so you could say, disregarding production variance and temperature dependence that maybe means something between 2,45 or 2,55V for that barrier…
Anyway, this would mean, each time the battery goes above 2,5V, it will again be discharged for at least one pulse of the FM3616CE’s internal boost converter, grinding down the battery to a certain voltage, until it won’t even recover to 2,5V anymore! Then it will probably really stop to discharge… but that might maybe be too late for the cell, I know electronics but I am not a battery specialist. Maybe someone else who knows more about batteries can even say that this is perfectly fine? But I am suspecting it is not, as the current will be quite high, for a 5V 1A discharge, this will already mean a cell discharge current of at least 2A, not counting the conversion losses.

To those who don’t know what I mean with “pulse”: The FM3616CE is very probably doing a DC/DC buck conversion for charging and a boost conversion for discharging, these kind of converters have a certain operation frequency in which they operate, for more details, see [1] below - basic electronic understanding is still required though.

In the end:
Maybe (just maybe) this is also just a lack of circuitry and the FM3616CE itself is actually quite good: Some resistors, diodes, capacitors, whatever might be missing…. When looking at the CHD-XS V1.1 circuit board, there are still multiple unpopulated parts and one 0 Ohm resistor. Maybe it would actually work if all/the correct parts would be populated……

Additional Information: I did only check for discharge cut-off doing all this, not for overcurrent protection so far!

Maybe I am experimenting more at another time. This is already over the limit of my time making sense to me (expect if I would buy 100+ and rework them, which I won’t be doing…), at least at the moment it is still fun as a short pastime :wink:

[1] DC-to-DC converter - Wikipedia

EDIT:
Ok I also verified that it is not overcurrent protected at all :-/

Any way to fit a protected 18650 cell in it ?

The larger cells with Chinese circuit won’t fit for sure - there isn’t enough space between plastic walls supporting the contacts to fit the cell even without the contacts. I don’t have any smaller protected cell but I don’t think you can make it fit either.

I got 5 of these, each different color, and ALL have the BAD chip, chinese shit.

I learned about the “Charger Doctor” and bought one from BIC. Costs $3 and I love it!
Here is the BLF review

And here is the $3 link to BIC

http://www.buyincoins.com/item/34684.html

Those powerbanks all fail on discharge protection because of a missing IC. This can clearly be seen on the pictures posted by alphazeta.

I have the original schematics/datasheets laying around here somewhere, its a bit of a mess, as they’re all in chinese.

Regards,

doc

I bought 3 of those:

http://www.ebay.com.au/itm/161228941965

They are also based on the 6316, but have the additional IC (protection IC) equipped. They disconnect at 2.5V and keep the bank disabled until external charging power is connected from the outside.

Regards,

doc

What is the chip identifying markings (the protection IC)?

According to the datasheet the protection chip should be DW06D. I have one battery bank from dealextreme which has an FM6316 and a chip marked CT2105 and it cuts off at aroung 2.6 volts.

Check out the price, then check out the second pic!
On sale!, regular price was $29.99

Has anyone recently received this (or any) power bank with the ETA9635 good chip?

Upon seeing this thread i contacted buyincoins a few days ago and they told me that this model is the one with the ETA9635 chip.

Absolutely, i made some pictures of mine, featuring the CT2105.

Regards, doc

WOW!! Nice pics…very clear and distinct…thanks!

Now to find a good heatsink for that good chip

I used a bit of brass strip glued down with a touch of silicon on my crappy version I soldered to a pair of Li Ion flat packs (then resoldered them parallel vs 7.4vdc power pack) I pulled out of an old netbook…really need to get me one of the good mobile power banks

I have FM6316FE (not FM6316CE) on board, but I can’t see CT2105 chip. However it stops discharge at 3.02V, haven’t checked the charge termination yet.
Can this be a good unit? Bought 15.05.14 from ebay, black one, board CHD-XS V1.1.

I believe they are talking about different one (this round 18650 power bank) which has an added CT2105 chip.

YOu guys thought you had it bad with what you received for your PowerBank. I got one off ebay and this is what I received:

Damn thing is empty! Obviously ebay got the description wrong and didn’t mention there were no components inside. ehhhh

So I’ve already got my refund, (big 1.87)…but now, where can I find the innerds for it? I’ve come across THIS at fastech and it looks to be correct (please chime in here!) , but haven’t come across the battery connections at the other end….

Help! My frugal budget got the best of me!

thanks
Dru

This looks nice except 1A is not acceptable for USB output.

Yes that unit might fit, might be able to just get some wire and solder the connections to a battery inside the box, the one that comes in a unit is a spring and pretty rigid material

I might have one laying around because I stripped one and soldered to a dual flat pack battery I pulled out of one of my kids busted netbook things