I bought fou of them from eBay seen the price point, to leave them in the car, the carry-on, etc for some emergency charge of ecig or phone.
No Joy. Used during Christmas to illuminate some LEDs on a window far from any main socket, then back to the junk drawer.
First, they have a 0.16 mA standby power consuption, which increases to 0.5 mA and up when the room is very warm (increase is due to a high capacity-low voltage ceramic capacitor, whose working voltage is less than 5 volts, and leaks like crazy).
Second, as others have noted, there is no lower voltage threshold, it bricks every and each unprotected 18650 it may happen to be fit in it. When I used them, I had to use some 18640 protected cells (a special shortened battery design for a very specific flashlight). Normally protected 18650 have truble fitting inside. And think, the protection circuitry of protected 18650 is not meant to be set off at each use, since normal pure (non-hybrid) Lithium Cobaltite cells are bricked at 3.0 Volts!
Third, mine has a charge LED (LED and charging current turns off at 4.20 Volt), but no discharge indicator. You don’t know if the charger is providing power if not for the indication on the charged device. The PCB has empty pads for one LED, one transistor and three resistors, which (I guess) is the power-on indication circuitry. Half-cent of dollar of missing parts, make me do a close guess of the profit made by the manufacturer, for something sold for three British pounds plus shipping.
Fourth, at 0.5 Amp load the Schotty diode has a forward voltage drop (checked with a scope) an hair less than 0.6 volts, to the point I tought it was silicon-silicon and not metal-silicon. No, it is metal-silicon of the worst possible quality, because at 1 mA direct current it produces a forward drop of 0.45 Volts. Therefore, the diode goes out of SOA when the load takes more than 300 mA.
By translating some chinese forums, it seems this power bank was meant to be used to charge soapbar phones using those ubiquitous unmarked blue 18650, which (in China) are used for almost everything.
I have a bunch of them removed from “20.000 mAh” power banks paid less than 10 US dollar each… they are 900-1000 mAh capacity, cathode 20% cobalt and 80% manganese. Low self discharge and internal resistance, provides 50 (fifty) full cycles before almost sudden failure (quality brand 18650 looses 0.04% capacity at each cycle). They have no PTC or other thermal safeguards. At the end of their uselful life, they just refuse to charge, with internal resistance climbing to ten ohm or so: No firework, just silent death. Their particular chemical structure makes them capable of going down to 1.5 Volt at each available cycle with no apparent damage. Not great performance in terms of capacity or life-cycle, but they sells for peanut. They pair well with this power bank, tho’.
I have seen on sale some DIY PCBs of the same size and socket layout used in this bank; it would be nice to swap the existing crappy PCBs with a proper designed circuit, as I like the plastic two-color box with a sliding door (even if it is made of poly-styrols, sort of a dense foam, not real plastic). I have been tempted to add the missing part and replace the underrated ones, but I avoided it as it would take a full day in the lab, just to get an half-Amp, one-of-a-kind power bank, just as the one selling in ASDA for 10 pounds; it has the same identical shape of our crappy one, a built-in 2600 mAh Samsung battery, all LEDs and safeguards, and it is made of metal. On comparison, I paid this crummy thing three times its real value!
Also the supplied USB cable is useless. 4 out of 5 cables failed after few months, it also doesn’t allow more than 0,4A… High internal resistance
Yesterday received a 1x18650 battery box from BIC. It’s FM6316CE based. Battery charged fine. But when charging my smartphone from it the battery got quite warm and the PCB even warmer. I was too scared to leave it connected during the night so disconnected when going to bed. Is this normal?
What kind of phone? The FM6316CE datasheet claims 80-90% efficiency for the boost-converting function. With a phone that draws 1A at 5V, thats 0.5-1W of heat. In my tests that skinny lead to the negative terminal is going to cause some power loss. There is also the resistance of the cell itself, how old is it?
The phone is Nexus 4. As for battery it’s a laptop-pull Samsung 2600mAh. My guess 4-5 years old from which 2-3 years it spent in a drawer. Voltage was 2.0V when I pulled it. Charges with no heat at all in same PB. As did another with same voltage from same pull only using TP4056 board.
Pardon me, but how much heat is 1W? 
Looks like the nexus 4 draws ~1A and has a ~2,100 mAh battery. That cell probably isn’t enough to charge it fully, so I’d guess that it will still be pulling close to 1A as the powerbank reaches exhaustion, that’s going to draw closer to 2A from the cell, increasing power loss due to resistance, plus the boost converter efficiency will decline as cell voltage drops. So, the rate of heat generation is going to increase throughout the discharge of the powerbank into the phone.
As for how much heat 1W is, not much, but by the end of the cycle, its going to be more than that, and its not a surprise that things are noticeably warmer. Whether its too warm is hard to say without a quantitative measure. People have different sensitivities to heat/pain, thicker skin, etc.
Looks like what you are saying is true. Yesterday I’ve tested the PB one more time. The battery stayed cool till about the end of charge then it got warm. N4 was drawing 700-800mA according to charge widget. The PB got charged to full (well at least the red LED was no longer lit) evening before and it only charged the N4 to about 84% from about 15%. Then the blue led started blinking and the phone was waking up endlessly. 18650 measured 3.14V after. Too bad it didn’t occur to me to check the voltage before connecting it to the phone.
Long story short, it seems to me that all those cheapest power banks aren’t worth the hassle. At least the FM6316CE based ones. I have one more cheap 1x18650 PB on the way with a PCB that looks a bit different. Maybe I’ll have better luck with it.
Meanwhile I will try your mod. Maybe it will improve the situation a bit.
The port of 5V-IN of my power bank is broken.I tried to repair it but it was a 5 pin 5V-IN port and it’s one of the pin was broken.I searched nearby shops but could not get the mentioned piece.Please help me as soon as possible.
Any info about this powerbank? I bought it from Banggood
From the pictures below can anyone confirm if the powerbank is safe for usage?
Thank you
I have a couple and they seem OK based on very basic tests I did: Unprotected batteries all fit OK. Charges battery to about 4.19V. I left it attached for extra 5 hours and the voltage did not increase (unlike the Miller unit I received which was heading for 4.28 after the same time). Charged my mobile phone with it (outputs about 0.9 Amp)
When not in use the drain from the battery appeared negligible (few microamp).
I got 5 of those tubular power banks from Banggood. Mine are exactly the same version as in post #142 above.
The one I opened had a 8 pin control IC marked 134N6P (I could not find a data sheet) (was TP4213-read EDIT2 below) and a 8205A mosfet.
A test with a Sanyo 18650FM 2600 mAh, a 5 Ohm load and an OLED USB tester showed me the following:
- They could not deliver the promised 1A. Two of them almost made it giving 4,5V out.
- I took the best one for a 10 Ohm load test with the Sanyo battery and got 1260 mAh out at a stable 5.05V and 0.48A. That is 5.05 x 1.26 = 6,36 Wh.
I assume that 8 Wh was utilized from the Sanyo battery (can hold up to 9Wh), stopping at around 3.1V. During discharge a steady blue light turns to blinking already at 3.7V.
- the efficiency has been around 6,36/8 = 80% , acceptable but not very good.
- The charging on that one continues past safe limits. I stopped charging at 4.25V where it was still charging with 0.3 A. That is not good.
EDIT: Another charging test with a (weak) laptop pull charged to 4.22V and stopped charging. That was fine, but the difference is strange. Anyway it is easy to open the unit and put in a battery that is charged elsewhere.
EDIT 2: I opened up another one and it had a TPower TP4213 all-in-one controller (easy to find data sheet) and no number or date on the board. The circuit was the same on both boards. Funny was, that this TP4213 was marked 134H7X. This was the only marking on the chip on the first board so I guess it also was a TP4213.
There is a neat 18650 “power bank” available from Gearbest: http://www.gearbest.com/chargers/pp_193542.html
It’s $3.99 as a deal atm. I cannot see any USB output port though, so it seems to be a only a charger!? Anyone got any info on this?
The cheapo powerbank, that started this thread, aside from fake Xiaomi powerbank, was my first lithium powerbank purchase which turned out to be crap and unable to take protected cells neither.
I will pass all this cheap unpredictable junk when it considers lithium batteries :D!
The real deal charger-power bank combos dont cost that much, they arent perfect, but they come from reputable brands, so less risk there.
I bought 3 of these recently, and none of them work properly. The charge phone for 3 mins then voltage drops to 3.15v then cuts out. Already tested batteries, and they are fine. When batteries are taken out they climb back up to about 4.1- 4.15 volts.
On ic chip it says
MP3401
1516A2
Posted a youtube video
How do you charge them back up once they are spent? Do you have to take them out and plop them on a charger?
Will bump this one up.
Got a power bank with this TPower TP4213(134V8P marking on it) chip in it, also got some SS24 chip, it came with Samsung ICR18650-30A battery, which, as I understand, is 4.35V battery?
Either way, powerbank is generic aluminum cilinder, silver color with custom engravings(promotional item), box said that its assembled in EU.
I will assume that it should be safe one, just not the most efficient one?
Could it be that charging up to 4.25V and still keeping on charging as mentioned in post #144 was because the chip is made to charger 4.35V batteries? Just a shot in the dark.
I have several of thees (and more coming). I have the same as the first post in this thread, and I have the same but with LED window, and I have the round metal thing.
I have checked now, and all have MP3401 1517A2 (1516A2) on them. Is this good or bad?
keep in mind that 1 amp at usb output means at leat 1.5 A from the battery ..
as voltage is boosted from 3.7 to 5 volts and include some boost circuit inefficiency etc.
on another power bank i did a test and at .9 amps usb output it was sucking 1.5 amps from cell and as the cell drained below 3.7 the current from battery increased to 1.9 Amps..
so if you are using laptop battery pulls i would recomend using a 2 cell model to increase efficiency..
their charger section (to charge the power bank itself ) seems to be using a linear charger which makes the ic hot..
Bought cylinder style power bank for one 18650. It have small board with only one chip. Price was only $1.5. Quality of aluminium case is amazing.
Board have chip marked as MP3401 (same board as in post #147) and I did some measurements with this power bank. Stand by current is 116uA. Output voltage with no load is 4.98V.
When charging internal battery red LED is flashing. When charging is done red LED glow solid. Internal battery is charged to 4.17V. When charging power bank is little warm. PB drains from wall charger 0.7A and after while current starts slowly drops and continue. Charging time was about 5h (2500mAh battery).
I tried charge my phone (Lenovo Z2) with 3000mAh battery. I put 3400mAh (NCR18650B) battery in power bank. Phone have 15% charge at start. Charging stop at 84%.
When charging phone blue LED glows. When voltage of internal battery is under 3.2V blue LED starts flashing. Cutt of voltage is 3.0V
If I charge my phone from wall charger, current is 1.4A. With this powerbank was current 1.1A and voltage droped to 4.7V.
With this high current is chip very hot and after white whole PB is warm, but it work, no smoke
Efficiency for output current 0.5A is 88, for 1A is 80. Measured with fully charged battery. When battery voltage droped efficiency was 75%. Tested with cold PB. Maybe is hot is efficiency even lower…
Output noise with 0.5A load is 6mV Rms and 24mV Vpp. With 1A load noise is 16mV Rms and 66mV Vpp.
For this price is very good product. It have good protection, so it will not over charge or over discharge you battery. Maybe will be good to disconnect data pins. Phone will detect this charger as USB and output current will be 0.5A. Charging will be slower, but much more efficient and chip will not be so hot.
Mildaine: I am almost sure you have bad battery.
(sorry for my bad english, it might help to somebody).