Charging can only be done from the high voltage end to the low voltage end. Therefore, the solar panel voltage must be higher than the battery voltage, only a little higher. charge or charge very slowly. If it is too high, it will be loaded incorrectly.
The 6.4V battery needs to be charged with a 9.5V or 10V solar panel. The theoretical voltage of the solar panel is a multiple of 0.5 and the output voltage will decrease after the loading. The charging effect is also closely related to circuit design.
As for how much current a 6.4V battery uses, it depends on the capacity of your battery and how long you want it to be fully charged.
How does the solar panel charge 12V? Battery ? Please tell me about the solar panel. What can be the minimum voltage?
First, let's calculate the time required for the solar panelto charge the battery. To charge a battery, you must supply enough energy to replenish the battery's charge. Here are the calculation steps:
Calculate the total battery power (in Wh):
12V * 20Ah = 240Wh
Calculate the solar panel to be provided per hour Energy autonomy:
(16V + 18V) / 2 * 50Wh = 850Wh
Now we can calculate the time needed to fully charge the battery:
Time (hours) = total battery power/energy supplied by solar panels per hour
Time (hours) = 240Wh / 850Wh ≈ 0.282 hours
Approximately equal to 0.282 hours , or about 16.92 minutes, can fully charge the battery, provided that the energy supplied by the solar panel is within its maximum range.
Next, let's calculate how long the light will last. The inverter converts 12V DC power from the battery to 220V AC power, but the power consumption of theThe inverter must also be taken into account.
The actual power consumption of the inverter is 2 to 5 Wh. Let's consider the highest value, which is 5 Wh.
The power of the lamp is 220V * 20Wh = 4400Wh
Now we can calculate the duration for which the lamp can be used:
Duration ( hours) = total battery power / (Lamp power - Inverter power consumption)
Duration (hours) = 240Wh / (4400Wh - 5Wh) ≈ 0.054 hours
Approximately equal to 0.054 hours, or approximately 3.24 minutes, the light can be used. Please note that this is only a rough estimate and actual usage time may be affected by many other factors, such as battery condition and inverter efficiency.
Generally, when the solar panel voltage reaches 17.5V, the 12V battery starts charging (the maximum open circuit voltage of the solar panel ins the 12 V system is 21 V). the solar panel charges the battery, the voltage will drop When the voltage reaches 13.5-14V, the rest of the voltage drop adds to itself. This is the characteristic of solar panels. Panel voltage must be higher than battery voltage to charge. Hope this helps you