Wireless charging Issue for TP4056 - Page 1
Forum section: electronics / projects

author: angelus2141
author_rank: Newbie
timestamp: September 10, 2024, 08:39:53 pm
content: HiFirst time posterIm using a TP4056 to connect an output for two red LEDs and to connect to a 800mah battery to use to light a model. I didnt like the idea of cutting a hole in the model for the USB port so instead I decided to use a wireless adapter. Space was a concern so I removed the USB port on TP4056 and wired from wireless adapter PCB to in+ and in- on the board.Initially I had trouble with the USB-C wireless adapter till i saw the + - and C symbol on the PCB and realised as its USB-C it probably needs some communication via voltage even for basic charging.Anyway I moved to a micro usb adapter and hey great it worked. Except when I removed the wireless coil from the charging pad mid charge and then put it back it doesnt continue charging. I tested a few times and found the battery had to be flat (indicated by the two red LEDs not being lit) before the charging would commence again.I think this might be an issue with protections on the board but Im not majorly electronics savvy (ive taken some classes). If i think (really hard lol) back to what i learned then could a capacitor across the in+ and in- on the TP4056 resolve this. Also any ideas of a value for the capacitor if it would work would be appreciated.Thanks in advance

author: Peabody
author_rank: Super Contributor
timestamp: September 10, 2024, 10:05:33 pm
content: Not sure what you mean by "wireless adapter". Anyway, could you post a schematic of how this is all connected? Hand-drawn would be fine.

author: angelus2141
author_rank: Newbie
timestamp: September 11, 2024, 01:16:46 am
content: Before most every phone had wireless charging built in, wireless adapters let you plug a wireless coil and PCB into your phone to recharge wirelessly.Im not so good with diagrams but here are some pictures. The wireless adapter is in the top middle of the first picture (the black and green thing)The white and gold to its left is the same thing without the black covering on.Second picture shows the TP4056 and the connections (excuse the terrible soldering, ive redone the wires so many time it looks awful now)

author: Peabody
author_rank: Super Contributor
timestamp: September 11, 2024, 02:08:32 pm
content: If this is a Qi wireless charging system, then I think there is a negotiation that takes place between the transmitter and receiver as to how much power is needed. And if the receiver detects no load on its output, it may signal the transmitter to shut down. But I don't know what would cause that. You have two LEDs plus the TP4056, so there should always be some load. But at low voltage there could be no load since the TP4056 will draw no current if its input voltage is below the battery voltage, and the Vf of the LEDs would not be met, so no current would flow.I don't know about the capacitor. I would think a resistor across the receiver's output would guarantee that there is always some load on the system. But I don't really know how the Qi protocol works.Edit: Sorry, I didn't notice that the LEDs are on the TP4056's output. So that means they don't draw any current from the wireless system unless the TP4056 is charging (otherwise they draw from the battery). So the wireless system sees no load unless the voltage is above the battery voltage, and the TP4056 turns on. I don't know how this is typically handled by the Qi system, but virtually every wireless charger would see this situation, so there must be an easy way to fix it.

author: angelus2141
author_rank: Newbie
timestamp: October 17, 2024, 06:24:27 am
content: Thanks for the help.I think the issue comes from protection as you say. The TP4056s I had were using DW01A chips but i bought some that came with DW01-9513 which according to the datasheets dont have all the same protections and the issue seemed to disappear. I dont like losing the protections but at least now i know.