Review: cheap 18650 mobile power bank

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?

Hard to tell, but according to http://www.chongdiantou.com/thread-2307-1-1.html it’s not very good…

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 :slight_smile:
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).

Welcome to BLF Ohm711! :beer:
Thanks for the detailed review. Where did you buy your power bank from? Link?

I bought it here: http://www.aliexpress.com/item/1pc-powerbank-Portable-Mobile-Power-Bank-USB-1x-18650-Battery-Charger-Case-for-Phone-for/32329517970.html
Many shops and sellers sell this item. But you can’t be sure which board will be inside.

Sounds similar to what I’ve bought from GB. Except my chip has no markings.

Almost same post as #145, only in reverse:
Now Gearbest sells a new Miller-ml-102-style 18650 charger, which is advertised as charger only but looks as if it could be a power bank as well:

http://www.gearbest.com/chargers/pp_177257.html

Thoughts?

At that price i would just go for original ml-102