Power bank with replaceable 18650 batteries. Where to get lithium batteries

Things tend to break. Sometimes you can just throw them away, but sometimes when they have any aesthetic value, or are a gift - it’s a shame to throw them away, especially if there is an opportunity to repair them.

And recently, a practically new Power Bank, given to a child for his birthday, was given a long life. Well, if it were just a box, then you could spit and forget, although you would feel sorry for the contents. But in in this case- it was one of the characters star wars, master Yoda:

And therefore, he needed repairs and bringing it to a new state.

I won’t talk about the Yoda powerbank itself: it was so-so - despite the fact that inside it contained as many as two 18650 lithium-ion batteries, each of them was only 750 mAh, so the total was about 1500. Nice item from Panasonic - one contains twice as much. But it looks cool.

After disassembly, it became clear that the problem was a board that had burned out for some unknown reason:

It literally burned through, and the voltage from the charger passed unchanged to the batteries, without reducing it to the required ~4.2V, and did not increase it when connected back to the phone. The idea that immediately came to mind was to replace it with the standard “popular” boards based on the TP4056 that I have:

unfortunately, could not be implemented for two reasons: firstly, its size (2.6 cm versus 2 cm) did not allow it to be placed inside Yoda, and secondly, I did not have a boost converter with a conventional USB output- not powerful, at least one ampere:

But again - the delivery price spoiled all the raspberries, increasing the original price almost three times! And then I remembered that at one time I saw a Power Bank for one element of the 18650 type, which people use both for its intended purpose and simply as a charger for their batteries. After spending quite a lot of time searching (it’s still a challenge), I finally found what I was looking for!

An excellent power bank (or rather a case), already with a board, for ridiculous money! Only 50 rubles - and that includes delivery!!! Looks reliable, excellent plastic, comes with a lanyard! Without hesitation, I immediately ordered:

Now it has gone up a little in price there, and costs 58 rubles, if you look again in “this product from other sellers” on the page via the link, you can find it for the same price from someone with a promotion. Well, here it is again - decide for yourself whether to order from the one he sent me, or take a risk and take from someone else. One way or another, but three weeks later (the track, of course, was not tracked), the box was already with me, in Moscow:

Everything is as expected - a green box with a circuit board inside, a white lid, and a cord included:

Which was immediately tested for functionality, and showed a voltage (when connecting it to the charger) of 4.10V:

In reality, with a fully charged battery connected, it shows 4.18V. Regarding the batteries, it is worth mentioning separately: the 18650 battery with a protruding “+” contact is not included in the length. It will only work with a flat “+” contact on the battery - or you need to “modify” the spring. And even more so, batteries with protection will not fit. It’s not difficult to see in the above photos - the “plus” is located on the side of the charging connectors, and the “minus” is on the blind end. When installing the battery, keep this in mind - when the polarity is reversed, it immediately burns out. Yes, just in case, I will definitely mention two subtleties that, as it turns out, are not obvious to everyone:

• Please note that this is just the body for the can. Battery not included. About 10 percent of those who bought it thought it was a full-fledged power bank with a battery inside :)
• AA batteries are not suitable. Only lithium-ion type 18650!

If you don’t close the lid, you can simply use it as a charger for the 18650. Moreover, if you are going to use it in this capacity, then closing the lid is strictly contraindicated! The latches on it are tight - once you slam it shut, it will be difficult to open it later, you can only pry it through the gaps in the large USB port. If you have already installed it and clicked it into place, then, of course, you can remove it - but it’s already problematic.

In stock, besides green - there is more various colors— black, white, yellow, blue, pink:

But remember - all caps are white, regardless of the color of the power bank! This was done so that the LED on the board could be seen - alternately blue:

then red:

depending on the operating mode (more on this later).

Since I did not take it for use as Power Bank, nor for use as a regular charger for 18650 - but only as a donor for Yoda - then I won’t photograph it against the background of a caliper, as I usually do. I'll just give the measured dimensions:

• Length=96.8 mm
• Width=24.6 mm
• Height=22.5 mm

The weight is not big at all, only 21 grams (there won’t be a photo either, take my word for it).

The charge control board is soldered well, I didn’t find any traces of flux, the dimensions are about the same as mine, about a mm smaller, in general we can say that 17.5 * 22 mm (due to the slightly protruding port, without it - probably about 20 ). The scheme is typical, but more on that below.

Principle of operation.

Charging the battery inserted inside:

When charging, it flashes alternately red and blue, such a police option :). After it is fully charged, when it reaches 4.18V, charging stops - it lights up continuously in blue (in theory, it should light up in red - I don’t know where the error is, either I have the same board, or I missed something somewhere in soldering). If it is already charged, at a voltage of 4.12V or more, charging does not start. I really liked the fact that when using a power bank as a charger, it can restore batteries that have run down even below 2 volts. So, the two batteries installed in Yoda, while this power bank was arriving before me, managed to discharge to 1.5 Volts, and I already thought that most likely I would have to throw them away, because a strong overdischarge is almost as harmful for them, as well as a strong recharge. But no, when connected to the board, it first began to charge them with a tiny current of about 0.08A, until it reached a level of 2.8 Volts, and then turned on at full capacity. Well, to the fullest, there were some adventures, but we will discuss this later.

Charging devices from the Power Bank:

When charging devices, it lights up blue without blinking, when it reaches 3.20V and below, the blue light begins to blink, when the capacity is complete - discharge to 2.9V - overdischarge protection works and the power bank turns off. When the consumer is disconnected while charging, the blue light lights up (or blinks) for another 3 seconds; if the connected gadget is fully charged, it continues to light up blue (it should turn off, but it continues to feed me with scanty currents).

But what was frankly pleasing was that my version of the board can work through and through - both to charge the power bank itself and to transfer energy to the device connected to it. Well, that is. If you connect both the charger and the consumer at the same time, it will both charge and charge. Of course, this requires a fairly powerful mains charger; 1A is no longer enough.

And now it’s time to mention a not very pleasant property. When charging a battery inserted inside the power bank, the microcircuit on the board gets extremely hot, and at the same time the charge comes with a current not exceeding 0.48A. Here's what it looks like using Yoda as an example of charging my batteries:

However, as soon as you touch the microcircuit even with your finger, the current instantly increases to 0.78 A, i.e. almost one and a half times! One problem: it’s impossible to hold your finger on it for more than a second or two, it’s so hot. Therefore, I had to attach a small radiator to this microcircuit using a mixture of thermal paste for the processor and super glue, made with my own hands from the sealed positive contact of this power bank. It looks, of course, not so hot (on the right above the batteries you can see the circuit board with a radiator), but it gives relatively stable results. high current charging:

Some people in reviews on AliExpress wrote that they even allow you to charge with a current of up to 0.94A (when the battery inserted inside is very discharged) - but I couldn’t achieve this (but they didn’t charge through - but mine does!). However, know that if your charging current is about half an ampere, then this is easy to fix, just remove the board from the case and put some kind of homemade radiator(even from aluminum foil), and insert it back.

Since even in externally identical power banks, from the same seller, and even of the same color, the boards differ from each other in layout (where the microcircuit is vertical, where it is horizontal, where it is on the right, where it is on the left) - I will give a photo of several options from AliExpress . She’s the only one there - eight-legged, and very hot, you can’t go wrong :)

With the discharge current, everything is much better: even before attaching a radiator, it was high, at 0.96 A when charging my Galaxy Note:

This can probably be considered the standard mode. After the battery inserted inside gives up about a third of the stored energy, the current drops by about 0.1A, to 0.86A, and so on. until completely discharged. At the same time, in the end, the discharge becomes permissible with a maximum current of 0.4A, if it is exceeded, similarly, the power bank is cut off.

The maximum that I was able to squeeze out of it after attaching a radiator and with maximally charged batteries using my load was 1.06A, when the voltage dropped to the maximum permissible according to the standard 4.5 Volts:

But here again - it all depends on the version of the board inserted into the case, since according to reviews on AliExpress, some versions cannot even charge through - when a charger is connected to them, the output to the device is turned off. I was lucky with this.

Results and conclusions

Well, with my task - to repair the Power Bank in the form of Master Yoda - this case for the Power Bank coped, if not perfectly, then well - for sure. Yes, of course, it’s sad that I had to construct a collective farm radiator for the microcircuit with my own hands, but, unlike many others, it allows through charging of the phone, charging both it and the power bank at the same time.

As for using it for its intended purpose, in general everything is also in order: a small case for power bank for 50 rubles (without battery), quite convenient for emergency phone charging (especially with a 3400 mAh Panasonic battery - it will allow you to fully recharge a good half of the phones once).

You can find a better design (it’s a matter of taste - some will have cylinders, some will have parallelepipeds) - for example, I like these better:

But, of course, it’s a little (30 rubles) more expensive, and without a lace with a ring. But, a big plus - if you use it not as a power bank, but simply for recharging - it opens much better (it simply unwinds) than the one I bought and considered in this review.

Let's bring together all the pros and cons.

Pros:

Fast delivery
+ Free shipping
+ Includes a lanyard with a ring for use as a keychain
+ Good quality both materials and assembly/soldering
+ Can be used not only as a case for a power bank, but also simply for recharging 18650 batteries
+ Several possible colors to suit every taste
+ Small size- fits anywhere, even in a pocket, even in a bag
+ Allows pass-through charging
+ Price!

Neutral:

* Controversial design, it can be better
* In all color solutions- white lid is used
* It is possible to use boards with completely different layouts, the quality varies from instance to instance

Minuses:

Untracked track
- There is a ring on the cord, not a carabiner
- Overheating of the microcircuit, which is why you have to do collective farm tuning
- Difficult to open after the lid is latched
- 1A limit for both discharge and charge

Summary.

You probably need to understand why you are taking it for yourself. If you just need a board made from it, then it is ideal for this: you will get it cheaper than if you bought this board separately, and in addition, you will also get a case with contacts for storing one 18650 battery - and what is it for in the future? Use it yourself - think about it yourself: even just to lay it on, or to build it into some children's radio-controlled car. Although it was disappointing that on my board (remember that even from one seller in the same lot they are different), the microcircuit got very hot, and I had to rebuild the radiator - but no one is immune from this, even if you take it separately.

If you want to use it as a backup power bank, it’s quite possible, although I would prefer to pay another 25 rubles and take a metal and at the same time cylindrical case - it looks more interesting (the real question is - will it charge through?). This charger, of course, is not for going outdoors for several days, but it would be nice to have it in your bag; it can extend the performance of your smartphone for several hours. Those that go with 2 batteries are a completely different story, because there it is already possible to find chargers with a circuit that allows you to charge 2A devices; there is no need to compare it with them - neither in price, nor in design, nor in size.

Likewise, if you want to use it as a charger for 18650 batteries used in the same flashlights and not only - yes, it is also quite possible, but you must remember that it is too difficult to open it, i.e. in fact, it can only be used without a lid, and this is not very convenient. Maybe in this case it’s even worth paying an extra 25 rubles?

Otherwise, the circuit itself works just wonderfully - charge-discharge indication, load detection - class, just a miracle of Chinese thought :) I was especially pleased with the possibility of through-charging devices - we charge both the power bank itself and the phone at the same time. Well, again, the price makes up for everything. Even these ones cost from 200 rubles or more. Well, here - less than one dollar - in my opinion, there are no questions at all.

Let them talk as much as they like about what is magical power bank giving the characteristics indicated on the packaging, but the most accurate thing is that you can assemble it yourself. Armed with exactly this thought, I ordered a separate power bank case and one already very well known for its quality. I ordered it, and when it arrived, I began my “research.” In short, this is the best you can buy, accurate and reliable.
The case came in a package.
The kit consists of the bank itself and the charging cord. The plug of this cord fits perfectly into routers, using this cable I powered the router with YOTA from a power bank, so it’s a fairly common connector, and as a plus, there’s always a backup battery for the router in case of a power outage.

At first, having examined the bank, I was in amazement, since when ordering there should have been indicators, they were listed on the box, and in front of me was a solid monotonous body with a power button.

I looked into bottom part, there are specifications.

2A to 2 USB port that's quite good parameters. Having connected the power, the indicators miraculously appeared.
On the front we see 2 USB ports and a port for charging with the included cable.


I connected into it, loved not only by me, batteries with protection from SANYO. Their tests have been done here many times and I won't waste your time on it. It looks like this.

The insides look very presentable, nothing superfluous, everything is high quality and neat. That is, we have a bank for 4 batteries with protection; by the way, you can use regular batteries without protection, but I prefer not to save on this. I use the same batteries for a reason; if performance is needed, this is how it can be achieved. Weight with 4 batteries is 298 grams. Each battery is almost 2600 mAh, that is, we have 10400 mAh, round this value taking into account the current conversion and get a bank of 10000 mAh, completely honest with minimal weight and maximum compactness and efficiency. I recommend this particular power bank to absolutely everyone; I use it myself for travel and in everyday situations, and it’s unlikely that anything ready-made can compare. Thank you.

P.S. The point of the review is how to assemble something of your own, something that you can really rely on, without disputes in forums and measuring equipment, having obviously good batteries and a simple and reliable case.