DIY Speaker - I need some help with power

Thread Starter

J12345

Joined Jul 1, 2019
6
Hello,
I am currently in the process of building my own Bluetooth speaker. I want to make it run on 18650 batteries that can be recharged when low.
I have built a circuit but am running into an issue.
I have 4 18650 batteries hooked up in parallel. The output from these batteries then feeds into a TP4056 board for recharging and battery protection. The output leads of the TP4056 board then feed into 2 voltage step-up modules. One that increases the 3.7v to 8v for the Bluetooth receiver module, and another that increases the 3.7v to 12v for the speaker amplifier that I have.
The only issue is that when I turn on the amp, it is powered for about half a second and then turns off. The output from the batteries then is only able to provide about 1.5v until I pull them out of their battery holder and reseat them (breaking and reconnecting the circuit).
I have disconnected the Bluetooth receiver and tested the amp alone to make sure that the receiver was not drawing too much current, but it still yields the same results.
Does anyone have any ideas about how I can fix this?
Thank you in advance
 

Thread Starter

J12345

Joined Jul 1, 2019
6
I thought I would clarify a little bit.
When I first connect the circuit with the audio amplifier off, I read 12v connected to the amp. Immediately after I turn the amp on, the power lasts about half a second and then it turns off. After I turn the switch on the amp off again, I only read about 1.5v connected to the amp. There is no other way to reset the original state (12v) than to break and reconnect the circuit. I thought that removing the load would reset it back to 12v but I guess not...
I also used a wall power supply to measure the current of the amplifier when it is turned on and not playing music and it was about 0.11 amps. Then for testing, I attached a 12v 0.4 amp load to the battery circuit and it is able to handle it no problem, so I am very confused.
Any insight is greatly appreciated. Please let me know if I am not making any sense. Thank you!
 

Wolframore

Joined Jan 21, 2019
1,475
Let's walk through this...

TP4056 module is a charger with overvoltage, undervoltage and short circuit current protect that limits output to 1 A. Any fault condition causes them to lock out... what bothers me is that you have any voltage showing at all after a fault condition which means you're still draining power.

Your bluetooth receiver power need is reasonable (prob about 50-200mA at best)

Your amplifier LP-838 requires more power... if you read through this the amp should get a 12-14V @ 3-5 A power supply. If you start to convert 3.6V @1 A to 12V you will see the issue. I'm not sure if the amp has an immediate current requirement after the caps are ready but regardless you will have to find another solution.
http://www.totlogcon.com/lp838/index.htm
 
Last edited:

Thread Starter

J12345

Joined Jul 1, 2019
6
Let's walk through this...

TP4056 module is a charger with overvoltage, undervoltage and short circuit current protect that limits output to 1 A. Any fault condition causes them to lock out... what bothers me is that you have any voltage showing at all after a fault condition which means you're still draining power.

Your bluetooth receiver power need is reasonable (prob about 50-200mA at best)

Your amplifier LP-838 requires more power... if you read through this the amp should get a 12-14V @ 3-5 A power supply. If you start to convert 3.6V @1 A to 12V you will see the issue. I'm not sure if the amp has an immediate current requirement after the caps are ready but regardless you will have to find another solution.
http://www.totlogcon.com/lp838/index.htm
Thank you so much for your helpful answer. I'm a bit of a noob when it comes to this sort of stuff and that made a lot of sense. I'll have to look for another solution to sort out power requirements.
 
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