Use a solar panel to charge a 3.7V/6600mAh lithium battery. The charging current is generally 1-2A. Generally, the higher the charging current, the faster the charging speed, but the power of the solar panel should also be larger. Since the end-of-charge voltage of lithium batteries is generally 4.2V, it is best to use a 5V battery panel to charge a 3.7V lithium battery using a solar panel. In this way, you only need to add a TP4056 lithium battery charging module. charging, and usually no additional voltage is required.
▲Single cell lithium battery charging module.
The TP4056 charging module shown in the image above is suitable for charging a single lithium battery. Its input voltage range is 4-8V, charging end voltage is 4.2V, charging current is adjustable, le maximum. is 1A, and there is a charging indicator light and a full indicator light. The red LED indicator lights up when charging, and the green LED indicator lights up when fully charged.
The wiring method of the charging module is as shown in the figure above. Its In+ and In- terminals are connected to the positive and negative poles of the 5V solar panel respectively, and the BAT+ and BAT- terminals of the module are connected to the positive and negative poles of the 3.7V lithium battery respectively. Since the charging IC is equipped with an anti-reflux circuit, no external isolation diode is required.
▲5V/2W solar panel.
The maximum input voltage of the above charging module is 8V, so a 5V solar panel can be used for charging, which can omit the voltage conversion circuit. Due to the large charging current, it is recommended to use 4-5 2W solar panels in parallel.
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