Increasing TP4056 Current

[Sv443]

Hi,
I am building a Bluetooth speaker right now but I have stumbled upon a really annoying problem: The maximum current of 1A is just too small to drive a 60W speaker. I have found a quad TP4056 on ebay that I have bought and it will provide 3A but the shipping takes too long. I have many TP4056 boards lying around and I was curious if I could just wire them in parallel to increase the current. Would that kill the batteries or the board or would it work fine?

(I'm using 18560 li-ion batteries and a single micro usb breakout board if that's important)

Thank you! 

[.rpv]

Hi, there's a better option: the TP5000 is a 2A charger, but from china...

You could use a standard DC-DC converter with current limiting, something like the LM2596, Dave has a video where he uses a lab power supply to charge a li-ion (or lipo). The TP4056 have sightly different output voltages from module to module... Example:



so this maybe an issue with stacking a few on parallel.

[Ian.M]

To get 60W out of a 4R speaker, you need 15.5V RMS across it.  That means your power amp needs to have supply rails greater than +/-22V to get enough amplitude.  You will need some margin on that to avoid clipping.   Assuming a class B amplifier, you'll need an average supply current (for each rail, at peak output power) of 1.75A.  A class D amplifier would be more efficient but would still need about 1.4A.   

There's no way you will get that sort of power level out of a single 18650 cell,  a boost converter running from paralleled cells would be horribly inefficient with such a high ratio of output to input voltage, and the TP4056 is useless for charging series packs of LiPO cells.

Even if you scale back your plans with a lower output power and speaker, it would take longer to charge the battery pack from a 5V 2A USB supply than you'd get for runtime.   A practical charger for a 60W portable speaker would boost from DC in from a 19V 4A laptop PSU (cheap and readily available)  to 51V at about 1.5A to charge a pair of series connected 6S LiPO packs to provide the two rails.

Obviously you'd need a balance charger design that can handle a 12S pack, with negligible draw on the balance connections while not charging, and you wont find a one-chip off-the-shelf solution for that.

[Sv443]

To get 60W out of a 4R speaker, you need 15.5V RMS across it.  That means your power amp needs to have supply rails greater than +/-22V to get enough amplitude.  You will need some margin on that to avoid clipping.   Assuming a class B amplifier, you'll need an average supply current (for each rail, at peak output power) of 1.75A.  A class D amplifier would be more efficient but would still need about 1.4A.   

There's no way you will get that sort of power level out of a single 18650 cell,  a boost converter running from paralleled cells would be horribly inefficient with such a high ratio of output to input voltage, and the TP4056 is useless for charging series packs of LiPO cells.

Even if you scale back your plans with a lower output power and speaker, it would take longer to charge the battery pack from a 5V 2A USB supply than you'd get for runtime.   A practical charger for a 60W portable speaker would boost from DC in from a 19V 4A laptop PSU (cheap and readily available)  to 51V at about 1.5A to charge a pair of series connected 6S LiPO packs to provide the two rails.

Obviously you'd need a balance charger design that can handle a 12S pack, with negligible draw on the balance connections while not charging, and you wont find a one-chip off-the-shelf solution for that.

Thanks for your reply, but I have an 8Ohm speaker and a TPA3118 audio amp. I don't know which class it is, though. Could I use a worse amp with my 60W speaker or do I have to buy a new amp and a new speaker?

[Sv443]

Hi, there's a better option: the TP5000 is a 2A charger, but from china...

You could use a standard DC-DC converter with current limiting, something like the LM2596, Dave has a video where he uses a lab power supply to charge a li-ion (or lipo). The TP4056 have sightly different output voltages from module to module... Example:



so this maybe an issue with stacking a few on parallel.

Thanks, I already bought one of those, but I wanted to accomplish the same thing with TP4056 boards. Is there no other way than waiting two months for the shipping? And also isn't it missing the protection features a TP4056 has?

[Ian.M]

Thanks for your reply, but I have an 8Ohm speaker and a TPA3118 audio amp. I don't know which class it is, though. Could I use a worse amp with my 60W speaker or do I have to buy a new amp and a new speaker?

The TPA3118 is a Class D stereo amp chip capable of up to 30W into a 8 Ohm load.
That will work for your speaker, although its not enough for full output.  Power it from a 6S LiPO pack for 25V fully charged, dropping to 18V at full discharge.  You'll need a 6S balance charger module, a boost circuit to get enough voltage for the charger (or a powerpack that puts out over 28V to give the charger enough headroom), and a UVLO protection circuit to shut it down at 18V to avoid over-discharge.  You'll probably also want a battery gauge circuit.


If you want to get more than 30W, dropping to about 15W at full discharge it gets a lot more complex, and you'll have to replace the amp, and also build it a regulated PSU rather than running the amp from the raw LiPO pack voltage.  To avoid the need for a high supply voltage, you'll probably want 4 ohm speakes if you go down this route.

I forgot in the analysis in my previous post that an amplifier can operate in bridge tied load mode, driving both sides of the speaker, which halves the supply voltage requirement, for the same output power at the cost of doubling the supply current, and also doubling the number of power amp output stages required.   That's why I've scaled back my suggestion to a single 6S LiPO pack and associated support circuitry.