Review: DIY Single 18650 Cell USB Mobile Power Bank

A good value single cell 18650 lithium mobile power bank which you have to part assemble yourself.


daDfarSpanTaistheKin says:

hi another nice video .
how strong do they hold onto regulation ? whats the ripple voltage?

fluke Nine says:

So this has an on off switch ?

I have had a few power banks from Maplins with 18650’s in them that has a parasitic drain.

rodolfo rodriguez says:


What is the difference between high drain batteries and protected/unprotected batteries? Is it the same term?

Deepak Dutta says:


Bill Sherman says:

I bought three of them. Two of them will turn on, but not turn off when pressing the button. They will eventually turn off under no load condition. One turns on and off perfectly, regardless of running on a load or not.

David Black says:

Just wanted to say thanks! Your reviews have taught me alot!

Tony Jobson says:

Thanks! that open circuit protection which seems to have protected a 2AMP test load had me thinking my battery was dead. you’ve saved me binning a perfectly working battery.

Radoslaw Biernacki says:

Thanks a lot for this. I was just about to buy one of those and hoping that somebody made review 😉

terratec1001 says:

4:07 – “…pressing the button doesn’t appear to do anything. No lights come on”.
Funny… I saw an LED going on and off on the very edge of the unit as you pressed.

Bob Wareham says:

Hi Julian
Thank you for the review very good but cant find that one on ebay do you have the ebay number please as there are so many and would like that one.

Demetrius Ramos says:

What kind of battery is it I try a regular battery and its to small

Tau Thianova says:

By ur video, jas purchased one almost same as urs except 18650 battery istalled. Thx for the video input and it is really fantastic to watch and listen too. Beside the built quaility and all the small parts inside, would you later if hve time can do a test to see how much is the engery efficincy conversion rate for this particular IC board? U know, the efficiency rate is qutie important for all the power banks on the market. I hve no tools and knowledge to get the exact figure instead estimating via charging a handphone according to the percentage. Keep up, really enjoy ur videos. Thank you very much. Cheers!

Somewhere between 10 and 45 says:

Wait can you just use it to charge your 18650s

Bigrignohio says:

On the one hand it is low capacity and quite inexpensive. On the other hand as it is inexpensive you can keep several laying around for emergencies.

W Sears says:

It looked as if you placed a protected cell in the power bank. Any downside or misbehavior if you have double-protection?

Ezi0AuditoreDiFirenz says:

I recently got a 2600mAh DIY power bank from eBay. If, I use a 3800 or 4900 bat instead of a 2600
Will it be alright? It won’t overheat or explode right? Thanks

Piotr Bomba says:

I can have 2600mAh@1.2V but when you if raise voltage to 5V you have only 500mAh.

Andres Hernandez says:

I baught this , but from frys,how long does the battery last it doesn’t say how long , would it be how long it charges ??

Ricky matrix says:

Cheers dude thought mine wasn’t working until I seen you plugging mint the charger to start it

Mandragoras says:

I connected a multimeter to the battery terminals to monitor the charging voltage. I noticed 2 things that worry me.
First, the voltage climbs up to 4.4 – 4.5 volts during charging. Isn’t it too much? Should I trust my expensive batteries with it or not? When charging terminates, the voltage of the battery drops to 4.23 -4.22 volts.
Second, as long as the voltage rises, I suppose the charger is in cc mode and it takes a very long time to reach the maximum of 4.4 – 4.5 volts. But then the charging stops very quickly. The expected behavior is the exact opposite; less time in cc mode, most of the time in cv mode. Does this charger only have a cc mode? And if during the phase when the voltage is constantly rising, the charger is actually in cc mode, why does the temperature of the chip marked “17” drop while charging advances?

RLJSings says:

I have one EXACTLY like this. It’s called a Tortoise powerbank. And i paid 20 pounds for it. The problem is that it makes a buzzing noise when I’m charging my samsung, is this normal? Why is it doing that noise?

Ben says:

Does it auto cutoff an unprotected 18650?

SuperGwiz says:

Hello – if i took the PCB out of this and connected it up to multiple 18650’s in parallel would it work as a charger for a higher capacity unit (but obviously slower) ?

Aboedi H says:

Where can i buy the battery for the powerbank??

Betsy Suarez says:

I have one just like this and I’m still trying to find the battery. You used a chargeable battery correct? I thought I had to remove everything once the battery died.

Mandragoras says:

1:41 That thing marked “17” gets very hot when charging the power bank’s battery. It could give one a burn.

2:03 Mine has a one amp diode. O_o

nrdesign1991 says:

What’s the charging current? 1A?

lolo ent says:

Hi, tnks for ur informative video my wife found one of these @ her job MO. Back, now I ask were can I find that cover hers is missing

birrbert says:

Nice video Julian! I just found your channel. This power bank has a very simple step-up converter on the output side. It really is the simplest I’ve seen. I’ve tested two so far and they both had more components than this one.

Christopher Allison says:

So is this unit using the protection IC to charge the cell too? I believe I’m right in saying many lipo/lion protection ICs have charge capabilities too but are they as comprehensive as the TP4056 you made a video about? I’m be interested to hook at meter up to the cell while it was charging in this unit to find out exactly. Many thanks for the interesting videos.

Datzfunk says:

That last unidentified chip is probably going to be the boost converter. Nice review. Building a power bank from scratch right now myself.

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