Replacing Li-ion Battery in Forever BS-330 BT Speaker Clone - Using Siemens C75 Battery?

Hello,

I bought a BT speaker from Allegro for ridiculous money as a curiosity. It is an identical clone of the Forever BS-330 loudspeaker, but it is listed as a noname on the Allegro and I also have it.

From the beginning, the problem was the battery, which it held for a minute after charging. So I dismantled the speaker ... a li-ion battery from 2008 inside and only with two pins + and -.

As I do not know electronics, and I would like to replace the battery, can I use a battery from a siemens c75? It has a little more capacity, 820 mAh instead of 450mAh.

The symbol of the original battery from the loudspeaker is 053450SL-1. The battery seems a little swollen to me. I also have concerns, because now I do not know if the system in this speaker has protection against overcharging the li-ion battery.

The speaker is charged via a usb cable, but I have no idea if the system protects the battery itself from overcharging in some way ...

I do not know if the photo of the plate will do something, but maybe someone will conclude if I can safely connect the battery from Siemens.



PS
Charged battery from Siemens is currently supplying my speaker, it has been playing for an hour, but I do not want to connect the USB power supply to start charging, because I do not know if it is safe.

Take a photo of the original rechargeable battery from the speaker

Green is a minus and red is a plus.

sebuli wrote:

The speaker is charged via a usb cable, but I have no idea if the system protects the battery itself from overcharging in some way.

Each device with a Li-ion cell installed inside should have such a protection, otherwise the cell installed in it at the factory would be damaged.

Hmm, that's what I thought, but maybe it's such Chinese crap that hence the slightly swollen original battery. I already got a speaker like this with a non-working battery. I just wonder why and where the clone of the forever loudspeaker appeared, here as much as I would trust that the security will be there. Unfortunately, I got a noname and I don't know if this protection actually works.

It swelled with age, as you wrote # 1: 2008. Take this old link apart and check if there is any electronics inside.
Greetings.

Well ... I didn't think about it The Siemens C75 charger has 620mA charging parameters, with USB 3.0 I can get 900mA, do you think that the circuit in the speaker has a protection that lowers the current to a safe value for the original battery anyway?

It will certainly lower, but it will take longer to charge. Using a multimeter You can check both the voltage and the charging current of a cell.

The loudspeaker already plays 3 hours on a Siemens battery, so far no feat, but the battery is also old, I feel that it is even from 2005. So solder to the cables and see how the battery behaves while charging?

sebuli wrote:

So solder to the cables and see how the battery behaves while charging?

You can, but before that, do this from my # 8 post, i.e. check the voltage and charging current (of course, after connecting the charger, cable with the appropriate USB output). Besides, in case of any problem, this speaker can be powered directly from power_bank without an internal battery.
Greetings.

Ok, I will check. Something else occurred to me. The original battery is 3.8V in specification, from Siemens it is 3.7V. The system could be built typically at 3.8V or will he cleverly calculate the allowable voltage for the new battery voltage? In the case of li-ion te 0.1V can be important when charging the battery to the maximum?

I checked whether the loudspeaker would work without a battery with only power supply, and unfortunately it does not work, you need a buffer in the form of a battery.

Edit:
The input from the computer's USB is 5.1V, but 4.72V is supplied to the battery. I will check the electricity.

sebuli wrote:

The original battery is 3.8V in specification,

Due to the old blindness which is associated with the problem of reading the data of this battery, please provide a link to its specification '

sebuli wrote:

I checked whether the loudspeaker would work without a battery with only power supply, and unfortunately it does not work, you need a buffer in the form of a battery.

And here you surprised me. There was no problem with the BT speakers that I fixed. However, these little Chinese handles can surprise you
PS
Apparently, man learns until death. Fear to be afraid to die, because you never know what else a Chinese man can surprise us with.
Greetings.

In the picture, the symbol of this rechargeable battery is not clear, NO OLD BLIND, please spit out these words :)

This is the only thing that I managed to extract from the Chinese sites.



I keep wondering about this voltage difference for both batteries, should I put a suitable resistor there, which will reduce my charging by 0.1V? I guess it would not work, because how to notify the system that it is to charge the battery until it encounters a lower maximum voltage, and not what is set.

@sebuli. I have not yet come across a 3.8V Li-ion battery. From what I could find it " Model Number: 053450sr; Type: li-ion; Nominal Voltage: 3.7v "so the same tension.
Greetings.

Hmm, I understand, I am only surprised that in google you can find these 3.8V batteries, e.g. some Samsung, although maybe fakes. Yesterday I tried to measure the current flowing from the cable that charges the battery to the battery plus, here I just plugged in with a multimeter and I do not know why, but the circuit did not work, so that my multimeter gave such resistance ...

Added after 4 [hours] 12 [minutes]:

I am writing a post under the post, but the voltage that goes to the battery during charging is 4.7V ... and I read on the Internet that if we have a 3.7V capacity, charging should be 4.2V. Also ... is what I'm doing now safe?

sebuli wrote:

the voltage that goes to the battery during charging is 4.7V ... and I read on the Internet that if we have a 3.7V capacity, charging should be 4.2V.

You read it correctly, the charging voltage of li-ion cells should not be higher than 4.2V. And here you need to make sure about the efficiency of your multimeter (what we wrote on PW).

Thank you for your help!