Haha, I'm like you. I also built one myself. It uses a boost circuit? The efficiency can reach more than 90%. does not require charging. Oh, the circuit, charging needs to be done separately!
FP6291 is a DC (constant current) mode PWM boost integrated circuit, suitable for lithium batteries (3~4.2V) 5V output, Application of 1A power bank.
The FP6291 is packaged in SOT23-6 and has an operating frequency of 1 MHz. It can be used with a small 3.3uh patch inductor to reduce the volume of the finished product.
The FP6291 has built-in overheat protection, shutdown protection, undervoltage protection and overcurrent protection, and can be connected to an external resistor to adjust the maximum current value (0.5~2.5A). ), which is the 6-pin ground resistor. 10K resistor is 0.5MAH, 100K means thate resistance is 2.5A current, you choose the resistance value to choose the current)
The circuit diagram is as follows. :
Can this battery use 5v1A charging socket? Thanks
You can set the output to 4.35V, then add a current limiting resistor, 0.5Ω~1.0Ω1W, the maximum load current is 1A. Charging time is difficult to calculate and estimate because it is difficult to calculate. no constant current charging. It takes about 5 hours to fully charge and it can be fully charged in 10 hours. The voltage is 4.35V. If you charge in a limited time, you can set 4.45V and remove it after 5 hours of charging. Do not continue charging for a long time.
Some strong light mobile phones can charge 18650 at 4.65V~4.85V, and they are still in use, but the battery life is unknown. Some portable walkie talkiess are also charged at 5V and the battery voltage is 4.85V. Although the voltage exceeds a lot, the power does not necessarily increase much.
If you use a 5V power adapter and then connect it to the adjustable voltage regulator board, the input and output voltage drop should not be sufficient. To get an output of 4.25V, the input must be greater than. 1V, which requires 6V AC adapter or battery power. You can use 5V to directly connect a 0.5Ω 1W current limiting resistor to charge a single battery. It can be fully charged in two hours, and 21 batteries can be charged alternately.
The standard voltage of lithium-ion batteries is 3.7 V, and the maximum charging voltage is about 4.2 V.
The standard voltage of lithium battery -ion of Samsung cell phone is 3.8V and max charging voltageThe limited voltage is around 4.35 V. The standard voltage for lithium-ion batteries is 3.8 V and it is perfectly possible to use a charger producing 5 V. I currently use a Samsung mobile phone. The battery inside the phone is the same as your photo and the charger is a 5V/1A square head.
Why is it used this way? Indeed:
1. To fully charge the battery at 4.35V, the charger voltage must be higher than the battery's 4.2V voltage. To ensure the battery is fully charged, if the charger voltage is also 4.35V, there will be no voltage difference between the battery and the charger, and no current will flow through it.
2. The output of the charger is 5V, which is inserted into the mobile phone. Part of it is diverted to the mobile phone and part of it is used to charge the battery. This will reduce the voltage and the voltage used to charge thebattery is no longer lower than 5 V.
2. There is also a lithium battery itself with a battery protection board. When charged to a voltage of 4.35V, it will automatically disconnect and no longer charge the battery.
For this reason, Samsung's original cell phone charger uses a charger that outputs 5V/1A.