USB Bluetooth with battery

Discussion in 'The Projects Forum' started by BWBW, Feb 15, 2015.

  1. BWBW

    Thread Starter New Member

    May 17, 2013
    Thanks for your help!

    I'm repeating a bluetooth battery powered speaker project that has previously worked: 5v usb bluetooth, 3.7v battery, 4.5-5.5v to 4.2v charger. In this batch, all parts and design are the same from what I've done before- except the bluetooth unit (previously got from, and this time got a few from ebay - seems to be the same thing, the type that has the aux stereo jack).

    The battery is fully charged and at 4.1 v. I turn things on and bluetooth loops an announcement to charge the battery. I added 1.3v from a AAA in series and the bluetooth unit no longer says to charge the battery, and system works. But, the charger now doesn't respond appropriately, neither the charged or charging light are on. When I put just the 3.7v battery in circuit, charger is happy again. And with just the 3.7 (4.1v) battery in circuit, I swapped out the first bluetooth board for another, but the 'charge battery' loop remains.

    What's the trick to get this bluetooth to work with battery power and also have the charger work? I wondered if it's about stepping V down from 5.4 to 4.2? But then wondering about the bluetooth operating V range, and why these units seem less forgiving than the previous ones.

    Thanks again!