Author Options:

*HELP* PCB reworking for charge status Answered

Hi All,

My company has tasked me with finding a solution to finding the charge status on our equipment mainly headphones we use.

This allows us to meet more tight time deadlines/quick turn arounds for masses of headphones,thus saving us time charging when its not always needed/necessary.

The problem I have right now is the headphones allow charging & sync(programming) via usb mini b, However they act like a one way valve not allowing power to flow back out via the usb mini b.. We are looking to be able to use one of these usb volt meters to read the charge status. From my research so far I know a reading of 3.80v - 4.20v is a 'roughly' fully charged battery that will last roughly around 8 hours, Anything less than 3.30v - 3.00v will be recharged due to events usually lasting anywhere from 6-7 hours this will not be sufficient enough to keep going.

I have asked my company for schematics for this pcb, However the factory is located in china & emails/questions are not always answered quickly... so any input on this would be amazing to speed this process up.

I have attached photos;

If anyone is able to help reverse engineer the pcb to allow this to work, your input would be massively appreciated!!

(After this is sorted, I had been tasked to integrate wireless charging if possible)


The forums are retiring in 2021 and are now closed for new topics and comments.

1 year ago

Just checking the battery voltage might not be enough to actually know how much charge is left.
Without a load the battery will always show a higher reading ;)
But it might be easiest to add two pins (preferably below surface level of the hpusing that are connected directly to the battery.
A USB plug can then be used as an adpater for the tester.
I wold solder two pins oto a USB plug (outer connectors) and then transfer the spacing to the housing / PCB to match the contacts.
After that you simply push the tester with the adapter plug onto the pins and take your readings directly from the battery.