To sum up, the fast charging method is suitable for solar panel energy storage device.Constant current charging method is a charging method to keep the charging current constant by adjusting the output voltage of the charging device or changing the series resistance with the battery. The control method is simple, but the acceptable current capacity of the battery decreases gradually with the charging process. In the later stage of charging, the charging current is mostly used to electrolyze aquatic gas, which leads to excessive precipitation of gas.Constant voltage charging is mainly a constant voltage charging for each battery. This method is simple and does not need to adjust the current when charging. Short charging time, low energy consumption, charging efficiency can reach 80. If you choose the right charging voltage, charge for a few hours. The disadvantages are: in the early stage of charging, if the discharge depth of the battery is too deep, the charging current will be very large, which will not only endanger the safety of the charger, but also damage the battery due to overcurrent. Constant voltage charging is generally used for low voltage batteries.