The battery voltage standard is 24V.
1. The standard battery voltage is 24V, but when fully charged it should be 2-3V higher than the battery voltage, but it will not exceed your generator's maximum output voltage of 28V, because the battery relies on the generator to charge, but if the battery is not charged for a long time and you use it frequently, the battery voltage will slowly drop to 24V or even lower.
2. When it goes down to 20V, if you connect the generator and charge, the voltage at that time can be around 23V or 24V. When the battery is slowly full, the voltage will increase up to. 24 V or more, or 28 V. Therefore, the battery voltage depends on the power of your battery. In theory, when the battery power is saturated, the generator voltage reaches the minimum level. cannot be lower than 24V.
3. Lhe voltage, also called potential difference or potential difference, is a physical quantity that measures the difference in energy produced by a unit charge in an electrostatic field due to different potentials. This concept is similar to “water pressure” caused by high and low water levels. It should be clarified that the term "voltage" is generally used only in circuits, while "potential difference" and "potential difference" are generally used in all electrical phenomena.