Self repair of Bluetooth speaker. — Battery questions.

Thread Starter

Adampm

Joined Nov 10, 2018
5
Hi all,


First time posting on the fourms! I’m also typing with my phone, please excuse typos.

I’ve broken down a bluetooth speaker from my childhood because the battery is abysmal, upon inspection the battery has no identifying characteristics aside of being wrapped in yellow plastic. It looks identical to a lithium ion arduino battery. I was looking for something longer lasting to replace it.

I was wanting to just get a replacement phone battery and just move the connector onto that, BUT i wasn’t sure if batteries were universal or if they provide different watt ratings/inputs like a power supply would.

Any advice would be appreciated!
 

k7elp60

Joined Nov 4, 2008
562
Welcome to this forum!
If is old it may be a NI-CAD or (nickle-cadium) 0r a a Nickle-Metal Hydride. Many batteries of the same size have different output ratings.
How many cells (individual) are wrapped in the plastic?. Sometimes the plastic wrap can be removed by cutting a slit. Sometimes it takes a small knife blade to do the cutting.
 

MisterBill2

Joined Jan 23, 2018
8,033
If the battery is rechargable then look at the output voltage rating on the charger. That should tell you what voltage it takes to charge the battery pack. Next, count the battery cells in the pack, that will give a strong indication, when used with the charging voltage, as to what kind of battery is required, or at least, what kind you have now. NiCad and Ni-metal hydride batteries produce about 1.2 volts per cell, while the Lithium ones deliver over three volts per cell, almost 4 volts when freshly charged. So that will allow you to determine what sort of battery pack it is. And a phone battery is a very expensive way to go, as I see it.
 

Thread Starter

Adampm

Joined Nov 10, 2018
5
Hey again, I'll post a picture of the battery -- I don't think it's individual cells, but I may just be assuming this due to inexperience. The speaker recommends 5W rating and a 5V 1A input. Would I be able to use a larger battery that can hold a longer charge or is that biased upon the output?
battery 1.jpg battery 2.jpg
 

MisterBill2

Joined Jan 23, 2018
8,033
The appearance of the battery pack implies 4cells, which would be wired in series for 4.8 volts, or so. Carefully cutting open the yellow plastic cover can verify this. Then you can purchase 4 replacement Nicad of NiMh batteries and wire them in and have another years's life from the player.
 

k7elp60

Joined Nov 4, 2008
562
If you buy individual cells and need to connect them in series, it is not a good idea to solder wires to the individual cells, as the heat from
the soldering iron can cause problems
 

MisterBill2

Joined Jan 23, 2018
8,033
If you buy individual cells and need to connect them in series, it is not a good idea to solder wires to the individual cells, as the heat from
the soldering iron can cause problems
TRUE, so you need to buy cells with welded on tabs, which is the only way to go. Then you can solder to the tabs without any risk of damaging the cell seals. The heat of soldering is what melts the cell seals and causes leaks and cell failure. Welded on tabs are the solution. The other option is spring clips to connect to the cells.
 

Thread Starter

Adampm

Joined Nov 10, 2018
5
Hey everyone!
Apologies for the hiatus, But apparently the yellow cover was covering the battery, which I was able to take off embarrassingly easy, and found that the manufacturer placed the black sticker part directly over the battery identification values.

here is a picture:
upload_2018-11-18_12-7-35.png

I was curious about if I wanted to make the speaker last longer between charges, would getting another battery with higher mAh hurt the speaker?
(Assuming that is what increases the charge time on a battery.


EDIT: So, the reason I was asking about the cellphone battery is because I do have a spare cellphone battery laying around that I do not use. Although it is 3.8V 1500 mAH (5.7Wh). It seems pretty close to the other one, but I am unsure if that's something that could break it.
 

Attachments

Last edited:

Audioguru

Joined Dec 20, 2007
11,249
The battery is a Li-PO. It charges to 4.2V and averages 3.7V or 3.8V during a discharge. Your cell phone battery is almost the same so you will not notice the difference.

If you use a much higher mAh battery then it might not become fully charged if the charger is simply a timer. It will not harm the Bluetooth speaker.
 

Thread Starter

Adampm

Joined Nov 10, 2018
5
The battery is a Li-PO. It charges to 4.2V and averages 3.7V or 3.8V during a discharge. Your cell phone battery is almost the same so you will not notice the difference.

If you use a much higher mAh battery then it might not become fully charged if the charger is simply a timer. It will not harm the Bluetooth speaker.
When you say much higher, what do you mean? Does much higher mean as much as an order of magnitude or as low as a thousand mAh? Thanks for understanding, complete noobie here.
 

MisterBill2

Joined Jan 23, 2018
8,033
When you say much higher, what do you mean? Does much higher mean as much as an order of magnitude or as low as a thousand mAh? Thanks for understanding, complete noobie here.
The charge delivered into a battery is related to the length of time multiplied by the charging rate. As an example, some Nicad batteries can only be charged at a constant current for a very limited time, excess charging time will destroy a new battery the very first recharge. So those devices must have a timed charge. So a timer for a short charge battery will not fully charge a larger capacity battery. BUT SUCH CHARGERS ARE JUNK!!! Any decent battery charger will include provisions for sensing the level of charge and reducing the voltage and current when a full charge is approached.
 

Audioguru

Joined Dec 20, 2007
11,249
The length of time an amplified speaker can play depends on how loud is the average sound level. It might play for 10 hours at a fairly low level but the battery might be dead after one hour when playing loudly. A battery capacity runs down as it is charged and discharged many times. So the difference in capacity from 1300 to 1500 mAh is meaningless.
 

Thread Starter

Adampm

Joined Nov 10, 2018
5
The length of time an amplified speaker can play depends on how loud is the average sound level. It might play for 10 hours at a fairly low level but the battery might be dead after one hour when playing loudly. A battery capacity runs down as it is charged and discharged many times. So the difference in capacity from 1300 to 1500 mAh is meaningless.
Thanks!
 
Top