Selecting 18650 Cells for Portable Speaker: Comparing UltraFire 8800mAh & Used Branded Options

Hello. He plans to buy cells to power a portable speaker of his own design. The amplifier consumes a maximum of 3A (power supply from 10 to 15v)
so 3 cells connected will give this volts. and here I have a problem which cells to choose? on the Allegro I found UltraFire 18650 for PLN 3.73 with a capacity of 8800 mAh Lion ,, 18650 battery, 3.7V 8800mAh Li-ion "the price is low so I don't know if it's worth buying because it seems very strange to me,
in the loudspeaker, I would like to give three cells twice, i.e. 52800mAh, so it is a lot, but I do not expect a 8800mAh capacity from them, and my question is how many cycles can 100 cycles withstand? and by how much their capacity can drop, and how to charge the connected cells (3 together) with 15v? and what power? and is he going to make such a charger that when they get charged, it will stop charging them. Thanks in advance for your answer

Added after 30 [minutes]:

is it better to buy used branded?

The maximum real capacity of this type of batteries (18650) is approx. 3300-3400 mAh. Values of the order of 4000 mAh and more for a 18650 battery are clearly a scam.
Ultrafire and other inventions with space capacities should be avoided from a distance - they usually reach 10% of those 8800 mAh, in addition, even the 3A output is unattainable for them ...

With such a project, where we want to connect 3 batteries in series, I would definitely recommend something new and branded - Samsung, LG cells, etc.
The economically advantageous capacity should be 2600 mAh. They should withstand 300 full cycles without much effort.

I could use more data on the amplifier itself - I assume that this is an impulse design and the 3A peak ones will appear extremely rarely ...

When it comes to charging such a package, you should equip or assemble a protection system for the 3S configuration - only such a system is connected to a voltage of 12.6V.

SPEAKERS_XP wrote:

We could use more data on the amplifier itself - I assume that this is an impulse design and the 3A peak ones will appear extremely rarely ....

Yes, the 3A peak measured with an ammeter, which appears very rarely, is 1.5A on average

Added after 3 [minutes]:

SPEAKERS_XP wrote:

When it comes to charging such a package, you should equip or assemble a protection system for the 3S configuration - only such a system is connected to a voltage of 12.6V.

and ha, and some schemacik, for example?

Sanyo are respected for their quality. They are often used in notebook batteries.

yogi009 wrote:

Sanyo are respected for their quality. They are often used in notebook batteries.

I see. And used sanyos with a real capacity of over 2ah will be good? (auction on Allegro tested on a tester) I want to buy a used one because I don't want to spend a lot on this speaker

For starters, you can try notebook battery recovery.

yogi009 wrote:

For starters, you can try notebook battery recovery.

I'd love to do that, but I don't have such batteries and I don't know where to get them

There is a lot of it on Allegro.
Enter, for example:
TESTED 18650

Alternatively, tell your friends that you are collecting old batteries from notebooks, usually for 6, 3-4 are in working order.

And ha thanks for the answers, I think I will buy on the allegro from noteboków, how many of them can be in one 6 battery? And could I charge them with a laptop charger?

You can really google things like the number of cells in a notebook battery. A little bit of my own initiative

Majsterkowicz22 wrote:

And ha thanks for the answers, I think I will buy on the allegro from noteboków, how many of them can be in one 6 battery? And could I charge them with a laptop charger?

There are usually six 18650 cells in the laptop battery and from experience I know that if the laptop battery / accumulator lasts approx.hours of operation of this laptop, the cells have an even greater capacity than the Chinese 18650 batteries of a nondescript company sold as new on the Allegro with the inscription 8800mAh, for example.

I would say this: Find original , working laptop battery, remove the cells, and "you will be satisfied" :)

The laptop charger will not charge either the entire battery without a laptop or individual cells. I don't even advise you to try.

To charge individual cells, you can use the TP4056 charger / chip from Allegro to which you connect the most ordinary phone charger or tablet with a nini USB / micro USB plug (depending on which one you order). The price of such a module starts from PLN 2, only it is the charger board itself without a cell / battery basket (Do it yourself).

The second option is to buy the cheapest powerbank for one 18650 cell (cost up to PLN 10)
I think every power bank has a 18650 cell. The 18650 battery is usually soldered there with cables, but you can unsolder it and give some plates so that you can freely change the cells you want to charge. And again, a phone or tablet charger is needed to charge the 18650 cell inserted there.

The third option is to buy a charger for 18650 cells. It is relatively expensive, but looks nice and you do not need to modify or solder anything.

I use the charger with the TP4056 module and I have no problems.

norbi45 wrote:

To charge individual cells, you can use the TP4056 charger / chip from Allegro to which you connect the most ordinary phone charger or tablet with a nini USB / micro USB plug (depending on which one you order). The price of such a module starts from PLN 2

Supposedly 2 zlotys, but then we do not have protection against overcharging or over-discharge, which these cells do not like very much. There are modules available for purchase (even in Poland) with the same chip with added cell protection.

yogi009 wrote:

norbi45 wrote:

To charge individual cells, you can use the TP4056 charger / chip from Allegro to which you connect the most ordinary phone charger or tablet with a nini USB / micro USB plug (depending on which one you order). The price of such a module starts from PLN 2

Supposedly 2 zlotys, but then we do not have protection against overcharging or over-discharge, which these cells do not like very much. There are modules available for purchase (even in Poland) with the same chip with added cell protection.

As for the TP4056 module, of course it has overload protection. It charges the battery to 4.2V, which is the voltage provided by 18650 battery manufacturers, then stops charging.
As for border discharge, I don't know what yogi009 is about. Tp4056 is a charging module, not a discharge module, that is, a current receiver.

norbi45 wrote:

As for border discharge, I don't know what yogi009 is about. Tp4056 is a charging module, not a discharge module, that is, a current receiver.

Generally, it is about both sides of the voltage, while the device is working, it is worth monitoring the voltage of Li-Ion cells and disconnecting them on time. Otherwise they will "fall" too low.

yogi009 wrote:

norbi45 wrote:

As for border discharge, I don't know what yogi009 is about. Tp4056 is a charging module, not a discharge module, that is, a current receiver.

Generally, it is about both sides of the voltage, while the device is working, it is worth monitoring the voltage of Li-Ion cells and disconnecting them on time. Otherwise they will "fall" too low.

I agree that discharging 18650 is lethal for them, but I recommended the charger here and I do not understand how the charger was supposed to control the discharge status of the battery if, after charging, we remove the battery from the charger and put it in a receiver.

If someone wants to monitor the discharge status of the 18650 battery in the receiver, you can solder something like in the diagram and connect it to the receiver's power supply (behind the switch to work after turning on the receiver). I checked it works.

I meant the TP4056 module with the discharge monitoring chip attached. In this case, the module is permanently mounted to the device and protects both sides of the voltage.

A very nice scheme, simple and probably effective.

yogi009 wrote:

I meant the TP4056 module with the discharge monitoring chip attached. In this case, the module is permanently mounted to the device and protects both sides of the voltage.

A very nice scheme, simple and probably effective.

No one in this topic asked about battery discharge control, so I do not know what this discussion is for.

Returning to the main question from the first post, I answer:
The very counting of the author of the question is incorrect "I would like to give two times three cells, that is 52800mAh" (each link is 8800mAh).
By connecting three 18650 cells in series, a battery with a voltage of approx. 12V is created, but the capacity remains 8800mAh (The voltage adds up, but the capacity in such a connection does not add up)
By connecting two such batteries in series, each with three cells connected in series, we get a battery of about 12V 17600mAh (The voltage does not add up, but the battery capacity is yes (2x8800mAh)).

Regarding the aspect of charging and discharging 18650 cells / rechargeable batteries.

You cannot charge three 18650 type batteries connected in series with a charger or other power source with a voltage of 15V, regardless of the current efficiency of this source.

Each such battery can be charged to a voltage of 4.2V. By charging several in series, there is no charge control over the individual cells in that circuit.

The receiver should also not connect such cells in series. Then we have no control over the discharge voltage, which should not drop below 2.5V on any of the cells in such a circuit.

Maybe someone say: a laptop battery is 14.4V or similar and there is a serial connection there.
Yes, there is a series connection of three batteries, but each of the three batteries is separately controlled during charging and discharging. That is why there is always an electronics board.

6800mAh battery, where is the power? It's more of a curiosity not to be fooled by nicely decorated crap.

A colleague dismantled the "Chinese"?

Yes, exactly Chinese, and the sad thing is that our native sellers continue to sell this kit and do not react to the opinions of distorted customers about the incredible capacity of such a battery.
When buying a battery, I suggest the weight (if it is honestly stated), maybe it is not a sophisticated way, but it works for me, for example:
UltraFire 5800mAh, which is almost what I undressed weighs 23g, and the three-year-old "tired of life" Panasonic 3400mAh 46g

Yes, it's an old method. For now, it works, until the Chinese handles start adding weight to the links

They started a long time ago, you can meet versions supplemented with sand.

Majsterkowicz22 wrote:

yogi009 wrote:

For starters, you can try notebook battery recovery.

I'd love to do that, but I don't have such batteries and I don't know where to get them

There is a container for electro-waste in the castorama - search only discreetly, because security is sometimes vigilant