TP4056 takes long time to fully charge Lipo battery - Page 1
Forum section: electronics / projects

author: kian0079
author_rank: Contributor
timestamp: April 13, 2023, 12:24:12 pm
content: Hi all,I am using the TP4056 charging IC configured with a charging of 580mA to charge a 850mAh Lipo Battery. Theoretically it should fully charge the battery within 1.5 hr based on the charging current. However, it take around 3hrs for the battery to be fully charged. I do not understand why this is so. Can anyone advise on how I can troubleshoot and find out what is the cause of this? Thanks in advance.

author: kripton2035
author_rank: Super Contributor
timestamp: April 13, 2023, 12:29:18 pm
content: did you measure effectively the current you fed into the tp4056 ?what is your main supply ? is it an usb plug ? then 500mA can be the max current available.

author: PeteH
author_rank: Unknown
timestamp: April 13, 2023, 12:46:38 pm
content: The part could also be in thermal regulation mode, dropping the charge current at lower output voltages to limit the die temperature.Heatsinking or cooling the module would improve the times in that case.

author: PartialDischarge
author_rank: Super Contributor
timestamp: April 13, 2023, 12:50:27 pm
content: The TP4056 has constant voltage mode at the end of the charge and can take some time to reach there. If you disconnect and reconnect the charger after 2h for example it will show up as charged

author: kjr18
author_rank: Regular Contributor
timestamp: April 13, 2023, 01:05:38 pm
content: Charge curve in datasheet will tell you that charging 1Ah battery at 1A might take about two hours. Below you can see it.

author: Peabody
author_rank: Super Contributor
timestamp: April 13, 2023, 02:12:28 pm
content: As for troubleshooting, you could measure the battery voltage during the charging process. It should gradually rise to about 4.2V, and then stay there for a while before terminating. The TP4056 terminates charging when the charging current drops below 10% of the full current value. You didn't say, but I assume there is no load circuit being powered by the battery/charger while charging is taking place. That would affect the termination time.

author: kian0079
author_rank: Contributor
timestamp: April 15, 2023, 06:39:42 am
content: I am using a 5V 2A output DC supply adapter. When I used a multimeter to measure the output of the DC supply, it gives 5.2V, but I assume its not a problem.I tried to measure the charging current coming out from the TP4056, and it shows around 140mA. Far from the 580mA that I had set. I disconnected the battery and measure its voltage which gives around 3.47V.Quote from: kripton2035 on April 13, 2023, 12:29:18 pm

author: kian0079
author_rank: Contributor
timestamp: April 15, 2023, 06:48:00 am
content: I think I understand what is happening. Even though I have set the charging current to be 580mA, I would not expect the charging current to be at a constant 580mA throughout (based on the graph). The charging current varies with the duration of charging and also the battery voltage.If based on the graph, charging a 1Ah battery takes 2hrs, I assume the calculation might be very roughly something likw -> (battery capacity/charging current)*2.If I were to extrapolate this, charging a 850mAh battery at 580mA would take about (850/580)*2 = 2.9hrs. Perhaps this makes sense?Quote from: kjr18 on April 13, 2023, 01:05:38 pm

author: kian0079
author_rank: Contributor
timestamp: April 15, 2023, 06:50:47 am
content: Thanks for the suggestion. I will try to get hold of the voltage logger and do the measurement. But I do have a current logging device I wonder if logging the charging current is equally useful? I am doing charging with the load disconnected.Quote from: Peabody on April 13, 2023, 02:12:28 pm

author: tunk
author_rank: Super Contributor
timestamp: April 15, 2023, 03:34:35 pm
content: Quote from: kian0079 on April 15, 2023, 06:39:42 amWhat's the cell voltage when charging at 140mA?If it's around 4.2V, then it could be a bad cell withhigh internal resistance.

author: kian0079
author_rank: Contributor
timestamp: May 03, 2023, 07:01:18 am
content: I am having this weird problem now with the TP4056. I am using 2 LEDs to indicated the charging and fully charged status. The LEDs are connected to the CHRG (Red LED) and STDBY (Green LED) pins on the TP4056. When charging, the red LED is flashing and if I were to hover my finger directly above the TP4056, the red LED stops flashing and stays on. This is happening to several boards and I don't understand why this happens.I am using a 10uF capacitor connected between pin 4 (VCC) and 8 (CE) and Ground. I also have a 10uF capacitor connected to pin 5 (BAT) and Ground. Anyone have any idea on the why the LED is flashing? Thanks in advance!

author: mikerj
author_rank: Super Contributor
timestamp: May 03, 2023, 08:21:54 am
content: Do you have an actual li-ion cell connected to the output and being charged or just the capacitor? If you only have a capacitor the flashing is normal.

author: kian0079
author_rank: Contributor
timestamp: May 03, 2023, 12:23:23 pm
content: I have a battery connected and charging, but the LED its flashing. And when I place my hand close to the IC (not touching), the flashing stops and it stays on.In some of the boards, the charging LED is off and when I place my hand close to the IC, it turns on.Quote from: mikerj on May 03, 2023, 08:21:54 am