These are cheap probably chinese headphones but otherwise work fine. It seems to have one of these batteries pictured below however putting a volt metre on it shows it is giving out 4.11 volts when fully charged, both connected to the charger and disconnected from the charger. The terminals are quite trick to get a reading from.
It appears so to be a Lithium-Polymer battery. I am very new to this and have several questions.
Firstly is the voltage reading telling me that I have got the battery identification wrong? This was taken with the USB plugged in and hence during charging?
If I am wrong how may I identify the battery. The battery has no markings like the one in the picture or link.
If I am right, can I simply get another Lithium-polymer with a higher mAH ratting and place that in the current battery’s place? If not, why not and what can I do.
Can anyone advise me if the battery type Lithium-polymer has a particular type of charging circuit. Would there be anything wrong with replacing the battery with another type, i.e. Lithium-ion or more even NiCd nor NiMH batteries?
Finally what is the difference between batteries with 2, 3 or even 4 wires?
The 3.7V rating is a nominal rating. The max you should charge these batteries to is 4.2V, but it’s not crazy that you would read 4.11V while charging, for three reasons:
Charge systems leave some room to reduce wear
Many voltmeters aren’t actually as accurate as you might think
The battery might be pulling down the charging system
The charging circuit will be specific to this battery chemistry. You don’t want NiCd or NiMH here. But LiPO and Li-Ion batteries have the same voltage limitations, so if you can find a Li-Ion that would fit, it would charge OK. I don’t know about differences in fire risk between LiPo and Li-Ion though!
EDIT: I was typing this as @mcdanlj was doing the same above lol.
Firstly is the voltage reading telling me that I have got the battery identification wrong? This was taken with the USB plugged in and hence during charging? 4.2V is the fully charged state and 3V is the minimum safe level of a LIPO. I would say that your battery is a fully charged LIPO.
If I am wrong how may I identify the battery. The battery has no markings like the one in the picture or link. There may be markings on the other side when you remove them. I think you are right about your identification of the battery type.
If I am right, can I simply get another Lithium-polymer with a higher mAH ratting and place that in the current battery’s place? If not, why not and what can I do.
Maybe. 1. It depends on whether the headphone charging circuit can handle the charge current for the larger battery 2. It depends on if you can fit it into the case. 3. It depends on if the headphone charging circuit is compatible with the replacement batteries technology.
Can anyone advise me if the battery type Lithium-polymer has a particular type of charging circuit. There are specific requirements for charging depending on the technology.
There are also battery charging modules on amazon this is a typical one:
Would there be anything wrong with replacing the battery with another type, i.e. Lithium-ion or more even NiCd nor NiMH batteries? No, given the charger and space in the headphones is compatible. There are lots of LIPO batteries on amazon:
Like minds think greatly! Even to linking to the same article.
At least, mostly.
Two points of difference:
Li-Ion and LiPos are not harmed by charging more slowly. A larger battery will just be charged more slowly. I’d be very surprised if a Li chemistry charge controller didn’t have current limits implemented. I can’t recall reading any Li charge controller datasheet without one.
I would be shocked if the charge controller on cheap headphones was a multi-chemistry charge controller. I think there would definitely be something wrong with using NiCd or NiMH and would definitely not switch battery chemistry. Stick with Li — either Li-Ion or LiPo. I personally would stick with LiPo and just find a pack with compatible dimensions.
I don’t trust charging circuits in cheap electronics. I don’t assume they are implemented with a charge controller. Some are cheap discrete attempts at meeting charging requirements. Often that is why the batteries do not last.
The point I tried to make was that you can change the battery technology if you also change the charger to match.
I agree with you, just replace the battery with the same type.
I haven’t seen 5V USB charging Li batteries without a charge controller, but I’ll take your word for it!
@robert please post one or more clear pictures of the circuit board in the headphones that this battery is connected to. We’ll need pictures that show the components on the boards, and you might need to move lights around until the pictures clearly show the lettering on top of the components, because we’ll need that lettering to look up the individual components to identify them.
I will get some photos, but, as you can see from those above, its ackward to get photos and the lighting is not ideal, but please hold on, it may take a day or 2!.
One more thing in the mean time. Even for Lithium batteries they come in sorts, some with two wires comming out, some with 3, possible even some with 4 and I have seen 6 on a laptop battery, though that seem to consist of 3 batteries together. Why would some batteries have 2 wires and others 3. Are these interchangeable. Is there a colour code to the wiring? They come often with plastic plug connectors which are asymetrical in design is the wiring of the 2 or 3 (or 4.5.etc) pins standardised?
Extra wires are likely for taps between cells wired in serial or for built-in temperature sensors that the charge controllers can use to limit current as fire protection.
Since what you have has only two wires, you could use any with built-in temperature sensors but wouldn’t be able to take advantage of those sensors.
Take your time getting pictures, it’s not like we’re paid support staff patiently waiting at the other end of a phone line. It’s often a good idea to choose a higher zoom level (if your camera has optical zoom) and take the pictures from further away, because the lighting will be more even and the picture will be more in focus.
Hi, this is probably not that useful, but below is the photo of the top of the circuit. Its an all in one. I could not work out how to remove it and it will be a job as all the buttons will need to be disassembled. I do not want to go there as there is a high chance I will break something. However, if there is anything useful please let me know. Thanks also to all those answering, providing information and suggestions. I am at present looking for batteries to fit the 4.5cm diameter place for the battery.
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It’s often a good idea to choose a higher zoom level (if your camera has optical zoom) and take the pictures from further away, because the lighting will be more even and the picture will be more in focus.